Model Engine Maker

Supporting => Boilers => Topic started by: gary.a.ayres on July 10, 2018, 10:03:06 PM

Title: 3 inch boiler build
Post by: gary.a.ayres on July 10, 2018, 10:03:06 PM
Hi -

I thought I should start a bespoke thread on this work in progress rather than indefinitely hijack my own 'introduce yourself' thread http://www.modelenginemaker.com/index.php/topic,8234.0.html.

Following my experience with a leaky check valve during the first hydraulic test, I followed advice from some of you and took two remedial steps: replacing the steel ball in the check valve with a nitrile one, and adding a globe valve between the pump and the check valve. This really did the trick, and the result was version 2 of my test rig which has no leaks in the water feed system. When that globe valve is closed, it's closed! Photo below.

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/807812.jpg)

And now the bad news: the improved system showed clearly that what I had thought was a repair was an improvement, but not a repair. The offending tube still leaks, albeit more slowly. During the test, the pressure dropped from 90 psi to 78 psi over a 30 minute period - better than it was, but a leak nonetheless. The photo below (top left tube) shows the problem - there is a gap under the fillet which I added, probably due - I think - to insufficient heat during the attempted repair. My plan is to reheat it and try to melt the solder which is already in place so that it will flow around and into the joint more than it has. The boiler is now back in some new pickle for 24 hours to get it as clean as I can prior to reheating it, hopefully tomorrow evening. I will, of course, use plenty of flux and follow the previous advice on giving the whole thing an overall background heat with propane before focusing on the flaw with oxy/mapp.

However, if anyone has any other ideas I'd be happy to hear them.

Photo below:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/807811.jpg)

gary
Title: Re: 3 inch boiler build
Post by: crueby on July 10, 2018, 10:59:36 PM
I had a spot like that, and wound up having to grind off the solder overhang so that I could clean the metal underneath properly, the pickle was not enough to get rid of soot/etc under there. If you have something like a Dremel rotary tool, and a small bur, that is very wuick to do. Then reflux, heat, and add a little more solder there as if it was a new joint being done - more reliable a method than hoping it will reflow.

Also, if you have more than one grade of silver solder, using one with a lower melt point for the repair can reduce the risk of opening up something else.
So close, keep at it!!
 :popcorn:
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 10, 2018, 11:10:08 PM
Thank you, crueby    :)

I did think about the grinding idea as I had heard it before, and in fact wondered if I would be given that very advice!

I think I'll give it a whirl tomorrow evening with my cheap and cheerful Dremel copy.

Regarding melting temperatures, I have already figured that in, as I used three different silver solders for the reason you suggest. Most of the soldering around the end caps was done with high or medium temp. I used low for the attempted repair and will do so again.

The encouragement is much appreciated - even knowing that you had a similar problem and fixed it is reassuring!

Cheers,

gary
Title: Re: 3 inch boiler build
Post by: crueby on July 10, 2018, 11:11:39 PM
Oh yes, I spent weeks getting my first boilers to be leak free! Later ones, just many days instead...   :facepalm2:
Chris
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 10, 2018, 11:13:04 PM
It can be done!!

 :)
Title: Re: 3 inch boiler build
Post by: zeeprogrammer on July 11, 2018, 12:09:30 AM
Keep at it! This is a very helpful thread.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 11, 2018, 06:14:41 AM
Thanks Carl.

As a beginner I'd have been in trouble without the advice I've been given here. I'm hoping that the thread will serve as a good resource for others too.

Keep at it I certainly will! I'll be glad when the boiler is finally steam-tight but too much has gone into this for me to quit now...  :ThumbsUp:
Title: Re: 3 inch boiler build
Post by: Gas_mantle on July 11, 2018, 10:17:13 AM
Hi Gary,

Its go to see you making progress on the boiler. I can't really offer any advice but I'm hoping to make something similar later in the year so it's interesting to follow along :-)
Title: Re: 3 inch boiler build
Post by: john mills on July 11, 2018, 10:34:25 AM
try to bring the tube plate hotter the silver solder should melt with the propane torch the hole end of the boiler will get close to the temperature needed.
Title: Re: 3 inch boiler build
Post by: Jasonb on July 11, 2018, 10:58:54 AM
The other good reason to grind away the blob is that it needs more heat to melt the solder second time around so using new will mean you don't have to get things quite as hot.
Title: Re: 3 inch boiler build
Post by: Gas_mantle on July 11, 2018, 11:05:14 AM
I don't want to hijack Garys thread but do you think I'd be able to build something similar using just a small MAPP gas torch ?
Title: Re: 3 inch boiler build
Post by: Stuart on July 11, 2018, 12:35:33 PM
The hard fact is no

Even for a small boiler the heat required is considerable at least a 25mm /1 inch burner head would get it done , donít forget it has to be hot and even , tube plate and foundation rings are the worst because you cannot easily inspect your work on the inside , so it needs to be heated though the job to get a good penetration of the joint

To the OP

I think your problem with the tubes not sealing was because you expanded the tube into the tube plate thus preventing any solder penetration of the joint have a read of Alex farmers book he recommends a rough rat tail file to give a bit of clearance in the joint , which is vital to get a good seal

Three roller tube expanders are normally used in steel boilers with copper tubes no other sealing was done


Stuart
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 11, 2018, 12:41:02 PM
@ John and Jason - good advice, thanks. Makes much sense. Will proceed down the route you suggest. Fingers crossed.

@Peter - feel free. Doesn't feel like a hijack to me  :-)

My guess is that the torch you are asking about may provide too localised a heat (albeit at a high temperature), whereas I think a more generalised source - such as a larger propane torch - is required to get the whole boiler up to temperature. But listen to me - the 'expert'  :lolb: .  Let's see what some of these people that actually know their stuff have to say about it.

gary

Edit:
PS - Stuart replied while I was typing the above, hence sequencing issue.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 11, 2018, 12:46:25 PM

I think your problem with the tubes not sealing was because you expanded the tube into the tube plate thus preventing any solder penetration of the joint have a read of Alex farmers book he recommends a rough rat tail file to give a bit of clearance in the joint , which is vital to get a good seal

Three roller tube expanders are normally used in steel boilers with copper tubes no other sealing was done


Stuart - I'm sure you are correct, and I will not be expanding the tubes on the next boiler I make. However, it's a done deal on this one. I take heart from the fact that there are ten joins in total between tubes and end plates on this boiler, and only one of them leaks. Not ideal, but hopefully fixable. Thanks.

gary
Title: Re: 3 inch boiler build
Post by: Gas_mantle on July 12, 2018, 08:22:40 PM
The hard fact is no

Even for a small boiler the heat required is considerable at least a 25mm /1 inch burner head would get it done , donít forget it has to be hot and even , tube plate and foundation rings are the worst because you cannot easily inspect your work on the inside , so it needs to be heated though the job to get a good penetration of the joint
Stuart

Thanks Stuart, I have wondered if my soldering torch has the guts

I was hoping to build something similar to the one Gary has built but possibly in a horizontal design. I did manage to successfully silver solder a foundation ring / base for my 5" dia boiler by using the ceramic burner that powers the boiler as an extra heat source to supplement my MAPP gas set up.

Fortunately the materials I have for the boiler were items that friends have given me so I don't have a lot to lose in trying. I did even consider buying a second MAPP gas torch and getting someone to lend a hand.

Ideally I need a more substantial torch but I don't have a garage or shed so storing a gas bottle indoors isn't ideal  :(
Title: Re: 3 inch boiler build
Post by: zeeprogrammer on July 12, 2018, 10:15:00 PM
I smell another thread getting started on torches and soldering.
I have the PMR #1 vertical boiler kit and what I'm being led to believe is my MAPP torch (similar but similar bigger to my propane torch used to make CrŤme BrŻlťe) won't do the job.



Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 12, 2018, 10:35:05 PM
I bought a Seivert propane torch specially for my boiler (though no doubt it will see other uses, and maybe even other boilers). It's kinda the industry standard for such things I believe, at least in the UK. The amount of heat it pumps out scares me. When I first used it I totally underestimated how fierce it would be so I didn't use enough insulation and  actually set my workbench on fire when I was soldering the boiler!  It was literally in flames... and on the shelf above, plastic containers melted and it was raining their content of stainless steel cap head screws in my workshop for a bit until I wised up (a little bit)  :Mad:

It was reasonably cheap to buy online and a small bottle of propane doesn't cost the earth either, but of course as you note Peter every single thing one acquires creates yet another storage issue.

I also have a small portable oxy/mapp kit which is great for a localised high-temp heat, and I have silver soldered steel pulley components together with it in the past. Used in tandem, the Seivert can produce a good overall silver soldering heat and the oxy/mapp can put a localised cherry on the cake. A very hot cherry indeed.

But tbh Peter (and Carl) if I were you I would think about biting the bullet and if possible getting a Seivert or similar big propane blaster despite the storage issue, as I do think that even a 3 inch boiler could be a misery with an under-powered torch.

By which I mean even more of a misery than it can be with an adequately powered one...  ;)
Title: Re: 3 inch boiler build
Post by: zeeprogrammer on July 12, 2018, 11:57:35 PM
Ah. I hadn't realized this is your thread Gary. I hope I'm not taking it on a tangent.

I just know so little about such things. To me...propane is propane. But it seems the type of 'torch?', 'blaster?' ... the thingie that puts out the flame...is more critical. No?

So using the same old propane tank, gotten from the local gas station, is fine but the 'torch' makes the difference?

I do know there are other fuels...but again, I don't know anything about them.

I'm interested in this because 1) as I said I have that PMR #1 boiler but 2) my dream since I was a kid was to build a working loco (like Kozo's stuff).

Fire, in whatever form, scares the 'crap' out of me but I know I have to learn about it.

Again...might be worth another thread. At some point I'll start one.
Title: Re: 3 inch boiler build
Post by: crueby on July 13, 2018, 12:59:12 AM
Yup Zee, the torch makes a huge difference. Nice thing on the Sievert handles (if you get the right series) is that it takes a range of nozzles. Smallest nozzle is a few dozen btu, biggest is a few thousand! I bought a range of them for the different jobs, boiler needs the biggy, piping the baby one. Runs off their regulator on a 20 pound propane grill tank.
Title: Re: 3 inch boiler build
Post by: Jasonb on July 13, 2018, 07:36:14 AM
It all comes down to the rating of the burner not how hot the particular gas burns, even a Sievert with a small burner won't do a boiler, for small ones something around the 7kw rating would do and double that on a big boiler .

Size wise a suitable burner at 7.7kw is 28mm across so Zee's kitchen one may just be a touch too small.

Also make sure you use a High Pressure regulator, a camping or BBQ with generally be low pressure, for these large burners you need a 4bar regulator to get enough gas through them.
Title: Re: 3 inch boiler build
Post by: Zephyrin on July 13, 2018, 08:58:41 AM
You have to dremelize these awful blobs of silver solder and start again...the little rotary oval mill with diamond shaped tooth works great for that !
absolute clean metal, pink copper and golden silver solder, degreasing with acetone, don't put fingers, good flux in a large area around the point of interest, and a fast heating up to the required temp to see the solder flowing all around the tube by capillarity, you can't miss that, if the solder melt in ball there is something wrong again.
You also may found 55% Ag silver solder, that melt at a lower temp than the usual 40%.

as said above, a propane bottle, 4bar regulator, a torch 500g/hour;

and yes, the heat output is tremendous, as is the return of heat by the bricks or ceramic blanket, you cannot use the little bits of brazing rod...wear gloves, even for a very short session, which should last for about 5 to 10 min.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 13, 2018, 10:08:21 AM
Hi guys, and thanks for all your thoughts.

@Carl - no worries! Doesn't feel like a tangent to me, and if it is then it's a useful one. Sorry, the term 'blaster' isn't the correct one - it was just me being poetic.  :)

The others have rightly pointed out that it's the spec of the torch and regulator that are the important factors. Here is the very torch that I bought - 28mm diameter, 7.7 kw, regulator 0 - 4 bar:

https://gasproducts.co.uk/gas-blow-torches/sievert-gas-blow-torch-kits/sievert-general-purpose-gas-blow-torch-kit.html


@ Zephyrin - thank you. You are a star.

 I have already 'dremelized' (great word  :)) the majority of the blobs off, but am still left with a fair amount of silver solder albeit much tidier than it was. Do you think it would be an idea to dremelize all of it off down to the bare copper? I can post a picture of it in its present state if that would help.
One of my problems - as Stuart points out further back in the thread - is that I flared the end of the tube so probably have no room between tube and plate for the silver solder to flow into. I'm now thinking that if I took off as much of the silver solder as possible I could then take a sharp-ended dremel burr and cut a tiny circular channel round where the tube joins the plate. The channel obviously would not go all the way through the metal but would hopefully act as a kind of seat to keep the silver solder where it is needed. This would not be capillary action but it might be better than nothing.
Just an idea... any opinions would be appreciated.

Finally (and I may as well say it now), this particular join is a pain in the neck, but - as far as I can see - the rest of the boiler is not too bad for a first effort, so I am in no way going to give up on it. My plan is to persist with the repair. However, I'm thinking that if I keep trying to fix it and still fail after several attempts it might be better to cut my losses and remove and replace the tube. Tug has mentioned this option in my previous thread. If I am driven to that, I'm wondering if drilling into the mouth of the tube from each end might be the way to go, possibly using progressively larger drills until I'm up to diameter. I believe that this method is sometimes used. In theory it should then be relatively easy to drop in a new tube (and not flare the end this time!).

Will be grateful for any thoughts on any of the above.

gary
Title: Re: 3 inch boiler build
Post by: Jasonb on July 13, 2018, 11:28:05 AM
As your tube has already been thinned by your attempts to expand it I would be a bit worried about trying to get back to bare copper as you will remove some of the already weakend tube end in the process.

If you later decide to remove the tube then have a look at  Ramon's "wide awake" thread were he starts to discuss the boiler to see how to mechanically take a boiler apart and end up with usable bits. If you do go for drilling out then I would mill the end off flush with the tubeplate and then use the head/table feed of the mill to lower a slot drill into the tube as a drill bit is likely to snatch.

http://www.modelenginemaker.com/index.php/topic,2851.0.html
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 13, 2018, 12:58:19 PM
Jason -

On the first point - yep, that makes sense.

Second point - thanks for the info. Am hoping I won't need to go that far, but will certainly bear in mind your tips if I do, and will look at Ramon's thread anyway.

Cheers,

gary
Title: Re: 3 inch boiler build
Post by: Gas_mantle on July 13, 2018, 01:49:57 PM
Gary, just as a matter of interest can you remember what gauge of copper you used ? I realise that isn't anything to do with the problem you are having but I'd like to compare what you used with the materials I have  :)
Title: Re: 3 inch boiler build
Post by: Stuart on July 13, 2018, 02:31:11 PM
Now I am getting very concerned

To build a boiler ( exclude the brass mamod type ) you have only two options

1. Build it to a published plan by a know designer
2. Do the required stress calculations for the working pressure and from that select the correct gauge of a known copper , also the size and spacing of any stays that the calculations require

If you are a member of a club consult you boiler inspector

I assume both these boilers are for private use and no members of the public will be nearby
In that case you will not need a boiler certificate but if third parties are involved then it need to be inspected and insured

Now copper boilers fitted with well made and sized safety valves seldom fail cin a atastrophic maner  but itís you hide . The point was made to me many years ago think about driving a 3 1/2 inch or 5 inch loco that boiler backhead is not far from the crown 💎

To sate a point a bit of 15mm copper water pipe looks ok it stands 80psi all day internal pressure , but external crush pressure in an annealed state after you have had it red hot is another matter

Sorry for the doom and gloom but I for one would not like to read of a member having a mishap


And finally no I will not do the calculations for boiler construction in copper/silver soldered model boiler

Steel boilers are a very different kettle of fish you should be a coded welder to make them


A disclaimer I have made 4 3 1/3 g and 6 5g loco boilers from plans but my last three I had professionally built due to the size and cost of the copper and silver solder
Title: Re: 3 inch boiler build
Post by: Jo on July 13, 2018, 02:46:03 PM
Good points Stuart.

Lets go back to basics: Gary who designed this boiler?

Jo
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 13, 2018, 03:08:12 PM
@ Jo - the boiler is based on a design by Stan Bray, scaled up from 2" to 3" with all dimensions of tubes etc as close as I could get to x1.5 in the materials available.
The original is in this book:
https://www.amazon.co.uk/Making-Simple-Model-Steam-Engines/dp/1861267738/ref=asap_bc?ie=UTF8

@ Stuart - Just to be clear, I am only building one boiler, not two.
Thank you for voicing your various concerns, but I am already aware of many of the points you make. For example, I have already bushed the boiler for a 45 psi safety valve, I haven't used ordinary plumber's pipe, and I know that a boiler needs to be inspected and passed before it can be used in public (I am trying to build it to a spec that might pass an inspection. If it doesn't, then it will be for my use only)....
Also, I hope you don't mind me pointing out that I have never asked you to do any calculations for me. I feel I have to make this clear because there's a line in your post that could be taken to imply that I have.

@ Peter - all of the copper for the boiler was purchased from model engineering suppliers to the required specifications  :).
I can't remember the dimensions and gauges off the top of my head but willl look them up over the weekend when I have more time, post them in this thread, and let you know.

 :ThumbsUp:

gary
Title: Re: 3 inch boiler build
Post by: crueby on July 13, 2018, 03:11:23 PM
It all comes down to the rating of the burner not how hot the particular gas burns, even a Sievert with a small burner won't do a boiler, for small ones something around the 7kw rating would do and double that on a big boiler .

Size wise a suitable burner at 7.7kw is 28mm across so Zee's kitchen one may just be a touch too small.

Also make sure you use a High Pressure regulator, a camping or BBQ with generally be low pressure, for these large burners you need a 4bar regulator to get enough gas through them.
I agree on the regulator, well worth it to get the one Seivert supplies fir the torches.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 13, 2018, 03:23:52 PM
Quote
I agree on the regulator, well worth it to get the one Seivert supplies fir the torches.

 :ThumbsUp:
Title: Re: 3 inch boiler build
Post by: Stuart on July 13, 2018, 04:31:11 PM
Gary
That line was aimed at the post above mine

I know you are making a only one but two are being discussed

I put that line in to prevent any misunderstanding if I was asked

Glad yours is from a published plan it should be ok

Sorry for the confusion
Title: Re: 3 inch boiler build
Post by: Gas_mantle on July 13, 2018, 04:35:31 PM
Gary
That line was aimed at the post above mine


In that case can I make it clear that I haven't asked for calculations either  ;)
Title: Re: 3 inch boiler build
Post by: Florian Eberhard on July 13, 2018, 05:40:39 PM
Hey Gary

I would grind off as much of the solder as possible. Just until you start to see the first spots of copper (a little bit is okay to stay there)
The Idea with the small tipped burr sounds good to me too, as long as you do not go further than approx. the half wall thickness of the end plate. Then apply a lot of flux before resoldering.
For the soldering job, I would use the sievert torch to heat up the whole boiler shell and then the oxy-mapp torch to get the joint up to soldering temperature when the boiler has reached a certain temperature (when it gets dark on the surface)
For that you will need to adjust the torch so you actually have a bit too much mapp. With that flame, the heat is a bit more even and not just on one point (not much though!). Then you will have to move the flame around the whole end plate so you heat it up evenly.
Also important: you should melt the solder with the heat of the copper and not with the flame! To apply solder, remove the flame and then apply solder to the joint.

I don't know if all silver soldering fluxes behave similar but the flux i know starts to get liquid and then when small drops of it start to move away from the flame i am just about to get to soldering temperature.

Oh and about what to solder first:
It looks like you first solderd the back end of the boiler into the boiler shell and then (in a second step?) soldered the tubes.
That is just the way i would NOT do it.
The reason is that you connected the heavy parts first and so the heat will wander off pretty fast.
That means you would have to bring the whole boiler shell and the back end aswell up to soldering temperature - more or less at the same time as you do it with the smoke tube which is pretty difficult without overheating the boiler tubes or the already soldered joints.

The better way would be to first connect the two endplates to the smoketubes and then finally put that element into the shell. This way the heat consumption of both parts is a lot less different and that makes soldering a lot easier.
Of course sometimes you can't choose which parts are joined first. In that case you should apply the heat in about evenly divided to the two parts as the relation of their mass is!

And finally if you have solder applied on a joint and the joint is big enough that it can't be soldered at once, the solder will always run to the hottest spot of the part / joint (as long as it is liquid of course)

So, good luck with your repair and keep trying.

Florian
ps: I always put a lot of flux on the joings - especially with boilers - as it is a lot less expensive as the amount of solder or even copper you need for a boiler. Not to mention the time you loose when you have to do it twice (which ususally for a hobby does not matter though)
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 14, 2018, 09:40:30 AM
Hi Florian -

Thank you so much for this.

I am knocked out by how much attention and expertise you have brought to bear on my boiler leak issue, and by your advice which I shall follow to the letter as you have clearly understood the situation completely.

Regarding my sequence of assembly, I don't know how you knew it but you are quite right. As a complete beginner, I was terrified above all of having big gaps between the end caps and the barrel, so I erred too much in the other direction, i.e. with caps that were so tight that I had to turn them down to get them in. I thought about making the caps/tubes structure first, but decided it could be a real struggle to get it into the barrel as a complete assembly, hence my decision. And, of course, I was unaware of the heat loss/conductivity issue that you describe. Something for me to do differently next time...

I also realise now that the bronze screws that I put in were unnecessary, especially given the tightness of the caps. They were just an expression of my insecurity  :)

A friend has just pointed out your Cochran boiler thread to me - it looks amazing, and I look forward to reading it.

Thanks again, and have a great  weekend.

gary

Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 14, 2018, 10:00:29 AM
Gary, just as a matter of interest can you remember what gauge of copper you used ? I realise that isn't anything to do with the problem you are having but I'd like to compare what you used with the materials I have  :)

Peter -

here are the details:

Barrel - C106 copper tube 3" diameter x 7" long (16swg)

End caps - made from C106 copper sheet, thickness 2.0 mm (14 swg)

Central tube - C106 copper tube 1/2" diameter (20 swg)

Outer fire tubes (x4) - C106 hard drawn copper tube 3/8" diameter (16g)

All of the copper came from GLR Kennions apart from the outer fire tubes, which came from Macc Models. These suppliers advised me on grade, thicknesses, etc.

All of the bushes are bronze, purchased from Polly Models.

I hope that's helpful - feel free to let me know if you need any more info.

All the Best,

gary
Title: Re: 3 inch boiler build
Post by: Gas_mantle on July 14, 2018, 10:02:58 AM
Thanks, I'll have a look at what I have later. I need to do a bit of homework and plan things a bit before I make a start  :)
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 14, 2018, 10:06:52 AM
Good luck, and Enjoy!

 :ThumbsUp:
Title: Re: 3 inch boiler build
Post by: Florian Eberhard on July 14, 2018, 01:37:42 PM
Hi Florian -

Thank you so much for this.

I am knocked out by how much attention and expertise you have brought to bear on my boiler leak issue, and by your advice which I shall follow to the letter as you have clearly understood the situation completely.

Regarding my sequence of assembly, I don't know how you knew it but you are quite right. As a complete beginner, I was terrified above all of having big gaps between the end caps and the barrel, so I erred too much in the other direction, i.e. with caps that were so tight that I had to turn them down to get them in. I thought about making the caps/tubes structure first, but decided it could be a real struggle to get it into the barrel as a complete assembly, hence my decision. And, of course, I was unaware of the heat loss/conductivity issue that you describe. Something for me to do differently next time...

I also realise now that the bronze screws that I put in were unnecessary, especially given the tightness of the caps. They were just an expression of my insecurity  :)

A friend has just pointed out your Cochran boiler thread to me - it looks amazing, and I look forward to reading it.

Thanks again, and have a great  weekend.

gary

Hi Gary

Most of the Information can be read on your picture:
The joint of the smoketube on the outer left has been overheated (the porosity of the solder tells me that). Therefore I take it you have tried soldering for a longer period of time and at some point also reached quite high temperatures. The rest is experience i made myself (not being able to solder a joint when the heat of two parts was not the same)

If you don't feel comfortable to solder the tubes and endplates first out of the shell, you can also do it in the shell. For this you will need to apply plenty of flux and put a piece of solver bent into a ring shape around every tube. (if you have a thick soldering wire you will only need to do 2/3 of the full circle - it only has to stick to the tube and not be able to run away when the water is evaporated from the flux)
Then heat up the whole thing to soldering temperature. As soon as you are there (you should do this with the big torch for an even heat distribution) and the solder penetrated all the joints, you can continue soldering the end plate into the boiler shell, feeding solder with a rod this time.

This whole process can be done pretty quick if you are prepared and then you don't have any issues because of burnt off flux.
Then repeat the whole thing on the other side (which should be covered in flux also - and before you start with heating up!)

The use of bronze screws is a really good idea! I usually do it with copper wire. This is a way to fix all the parts to where they belong and not at all a sign of not knowing what you do (rather the opposite!)

Cheers Florian
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 15, 2018, 09:42:08 AM


Most of the Information can be read on your picture:


Well, I still wonder if you might be a detective as your day job. Or if boilermaking might be your day job and detectiving a spare-time hobby   :)  .

Your explanation is very helpful indeed. I have been busy with other things the past couple of days but when I get back on to the boiler I'll do as you suggest.

There's only one thing now that I'm not too clear about: other knowledgeable people on this forum have suggested that I flux the whole end cap, which I think is to protect the other joints if the solder should remelt. However, in your very interesting Cochrane boiler thread (which I am currently reading right through), you say that you only flux the spots that are going to be soldered. I realise that there are different ways of doing things, but am interested in whether or not you recommend that I cover the whole end plate in flux, or just flux around the end of the tube.
Also perhaps worth bearing in mind here that I have used three different grades of silver solder overall, that the end plates and tubes were done with high and medium temp solder, and that I am now using low temp for the repair.
Having said this, it may well be that on such a small area any flux will run all over it anyway...

I hope others looking in don't feel I'm ignoring their suggestions or going round in circles with my questions, but I would really appreciate your thoughts on this particular point, Florian.

Finally, on the bronze screws - ok, I'll take the credit for that while it's going - thanks!   ;)

 :ThumbsUp:

gary
Title: Re: 3 inch boiler build
Post by: Stuart on July 15, 2018, 12:23:40 PM
Clean work , plenty of flux ( esp. on tube plates and foundation rings)

You can limit the flux a little for bushings

Flux is cheaper than silver solder and gas

And do not do it in bright sunlight ,you will not see the colour of th job subdued light is best
Title: Re: 3 inch boiler build
Post by: Florian Eberhard on July 15, 2018, 04:21:02 PM
Hi Gary

Nope, but i am an engineer and so i guess it comes with being an engineer to observe every detail  ;)

I would have just put the flux where I need it. But plenty of it then. The flux would by the way not protect the other joints pretty much (only from oxidation) since the solder is already in its place and made contact to the boiler components.
I also have to mention that this (flux thing when reheating it)  is not any knowledge that I was taught, its just what seems logic to mee. So probably there is a reason for putting on some flux again that i don't know.

Oh and Stuarts point about the sunlight is a very good one too! Because in bright sunlight, the copper will look only dark whereas in the shadow you would see it glow dark red!

Florian
Title: Re: 3 inch boiler build
Post by: Jasonb on July 15, 2018, 04:33:34 PM
One reason for fluxing the whole end is that if the heat spreads and causes a hole to open up around another tube and you see it you can quickly feed in some more solder. If it were not fluxed you would then have to let things cool, then have the cleaning problems again followed by resoldering another joint. I'd rather spend 10 seconds putting on a bit of extra flux than risk having to go through the whole process again.
Title: Re: 3 inch boiler build
Post by: Florian Eberhard on July 15, 2018, 04:45:01 PM
Hi Jason

Though without flux, the hole wouldn't open up as easily as with flux.
But if there is the danger of a hole opening up, I agree it is easier to just put some flux on it and you're good then.

Florian
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 15, 2018, 04:53:11 PM

Nope, but i am an engineer and so i guess it comes with being an engineer to observe every detail  ;)



And me? I'm a family and systemic psychotherapist for my job, so it's fairly similar in that respect :)  .


Thanks to you all, gentlemen.

I'll think about what you have said and make a decision about the flux.

Hope to get it done before I go off to France next weekend.

Will let you know how it goes.

Florian - your Cochrane boiler is a thing of rare beauty.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 17, 2018, 10:58:59 PM
The saga continues.

Following good advice from quite a few of you guys, I 'dremelized' most of the silver solder off the offending tube end, swabbed it with acetone and put a large dollop of flux around the end of the tube. When heat was applied the flux ran all over the cap anyway so not a dilemma after all.

Then began my first problem: no sooner had I got the whole boiler up to the temperature at which it turned black than the Sievert torch went out and was very tricky to relight again in the 'heat' of the moment   :) . I struggled with this for a while, particularly with the fiddly and counterintuitive bottle regulator that came with the torch. At this point I was acutely aware that all the time the boiler was losing heat, so I swapped over to the oxy-mapp and concentrated on the end plate. I found it difficult to hold the oxy/mapp mixture steady to a 'soft' flame, and this torch also went out on me and I watched in dismay as the top of the boiler turned into a sooty mess as I fumbled about trying to relight. I despondently let the boiler cool and threw it back into the pickle, resolving to find out what I was doing wrong with the torches (though I didn't remember having this much trouble with either of them before apart from the time the nozzle of the Sievert was loose) and thinking I was back to square one again.

Half an hour later I fished the boiler out of the pickle to look at it. Imagine my surprise when I saw that the joint in question had formed into a smooth, round pristine collar of silver solder round the neck of the tube. It's now the best-looking joint on the boiler, and unless anything else opened up with the heat (and I have no reason to think that happened) it may be that the boiler is now intact.

I say 'may be'. It went straight back on to my hydraulic testing rig. When I upped the pressure I noticed a leak from where the neck of the adaptor I had made for the test pressure gauge was screwed into the boiler bushing so I took a spanner to tighten the adaptor ... and sheared off the threaded section at the end!
Wonderful things, screw extractors...

Maybe I should have made the adaptor out of bronze instead of brass... but in any case I'll have to make another one before I can re-test the boiler, and realistically I may or may not have time to do this before I go off to France on Saturday. I might have to spend the best part of the next three weeks in trepidation about the moment of truth that I have to face shortly after I come back on 6th August.

Am I completely useless or is this normal for beginners?

 :paranoia:

gary
Title: Re: 3 inch boiler build
Post by: crueby on July 17, 2018, 11:08:48 PM
Great dumb luck on the joint, paid for by the sheared off adapter.   :zap:


Possible that the gas bottle went empty? If its a small one, they dont last long, the big gas grill (20 pounds here) are great, easy to judge how much is left.


Here's hoping on the test!


 :popcorn:
Title: Re: 3 inch boiler build
Post by: zeeprogrammer on July 17, 2018, 11:16:56 PM
than the Sievert torch went out and was very tricky to relight again in the 'heat' of the moment   :) . I struggled with this for a while, particularly with the fiddly and counterintuitive bottle regulator that came with the torch. At this point I was acutely aware that all the time the boiler was losing heat,

Half an hour later I fished the boiler out of the pickle to look at it. Imagine my surprise when I saw that the joint in question had formed into a smooth, round pristine collar of silver solder round the neck of the tube. It's now the best-looking joint on the boiler, and unless anything else opened up with the heat (and I have no reason to think that happened) it may be that the boiler is now intact.

I say 'may be'. It went straight back on to my hydraulic testing rig. When I upped the pressure I noticed a leak from where the neck of the adaptor I had made for the test pressure gauge was screwed into the boiler bushing so I took a spanner to tighten the adaptor ... and sheared off the threaded section at the end!

We could almost trade posts today and no one would notice. (Although I was more mum about my various disasters. Not a good thing really. Best to be embarrassed and help others. Actually no reason to be embarrassed either. 'newbie' = sometimes does things wrong until learned.)

Am I completely useless or is this normal for beginners?

Normal! Else I am in serious trouble...or rather uselessness.  :Lol:
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 17, 2018, 11:47:13 PM
Thanks guys.

Chris - yes, 'dumb luck' was the phrase running through my head this evening...! At least having paid for it I don't need to feel that I cheated  :)

It wasn't the gas bottle because to exclude that I went out to the garage and bought a new one. Googling it revealed that quite a few people have this kind of problem with Sievert torches. I suspect it might just be about being more precise with the various valves, but it warrants more investigation for sure.

Carl - thanks for the moral support. No doubt it is by muddling through these scenarios that we gradually learn...

I do hope that other people will benefit from the wealth of information that all you guys have offered in this thread.

Will keep you posted on the eventual hydro test. Or re-test I should say.

All the best,

gary
Title: Re: 3 inch boiler build
Post by: crueby on July 18, 2018, 12:15:50 AM
Is your torch the type that screws on a bottle the size of a thermos? Sounds like possible clog in a jet. Common issue in the smaller butane burners, with contamination in the gas. I have not seen that in the propane or mapp ones (at least yet).
Title: Re: 3 inch boiler build
Post by: Kim on July 18, 2018, 05:43:32 AM
Gary,
This all sounds quite normal to me.  But think how boring it would be if everything just worked right the first time and there was no learning curve?  What would be the fun in that?  Part of what makes this hobby so interesting is the many things there are to learn.  And doing it wrong several times (many, many times, if you're me) is just part of the process.

I usually get something to work after the first or second try (like sliver soldering) then come back to try it on a different part later, and have yet more problems of a different kind.  Its all part of the learning curve. And what makes it so fun when you do it right!

You've got to enjoy the process!  That's what makes it fun, right?  :Jester:
Kim
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 18, 2018, 05:45:56 AM
Chris -

No, it's one of these:

https://gasproducts.co.uk/gas-blow-torches/sievert-gas-blow-torch-kits/sievert-general-purpose-gas-blow-torch-kit.html

Used with propane bottles of various sizes. I did wonder about the possibility of a partially blocked jet though... will look into that.

Kim - there is wisdom in your words. You are absolutely right. A philosophy with which I agree but need the occasional reminder to follow!

Thanks,

gary
Title: Re: 3 inch boiler build
Post by: Jasonb on July 18, 2018, 09:22:39 AM
As they both went out did you have more firebrick or insulation around the boiler as that can starve the burner of fresh air or worse still working in a close space.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 18, 2018, 12:22:10 PM
I did have a fair bit Jason. Will bear that in mind, and experiment a bit before next time.

However, I think it was more than that. The Sievert was hard to light and went out even when not near the job.

Cheers.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 21, 2018, 02:34:41 PM
 :cartwheel: Yay! Yaaay!!! YAAAAAAAAY!!!  :cartwheel:

I postponed my departure for France until Monday as I couldn't bear the thought of two weeks of suspense over the boiler while I'm away.

This gave me time for a hydraulic test today after the above repair.

Sorted!  :ThumbsUp:

Sat at at 90 psi for ages. Miniscule downward creep of the gauge needle at first, but this stopped after tightening one blanking plug and one pipe union nut which were oozing tiny beads of water (I understand that a slight initial pressure drop is common even on an intact system anyway, due to general settling in). After that, 90 all the way until I disconnected the pump, at which point it dropped to 85 then stayed there for half an hour, when I decided the boiler is now fixed. No leakage at all from any point on the body of the boiler.

Thank you all so much for the help and support you have given me on this. I would have been lost without you. The knowledge and expertise of people on this forum is incredible. You guys are amazing!   :LittleAngel:

I can now close the pages of this dark chapter of history, and on my return from France open them on the next one - which I understand will be another hydro test at 1.5 WP with all fittings in situ - and the trials and tribulations that await therein...

 :)

gary

Title: Re: 3 inch boiler build
Post by: Stuart on July 21, 2018, 03:17:27 PM
Glad you have it sorted out with a good 2x test

The 1.5 will be a breeze ,then a steam test to set the safety

It is a known fact that a new boiler will not hold water but will steam

My first 3 1/2 loco boiler William had a pin hole in the dome flange joint ,it was under test we had a small drop of pressure one of the witnesses walked past and got wet , the jet was so fine you could not see it but hold your hand near you got damp, what happened next you ask our boiler inspector passed the test as the boiler was structurally sound he said that will disappear on first steam up it did and there was no sign of any deposits in that area .

Yes we strive for perfection but a good inspector is worth his/her weight in gold

As a side note most full sized riveted steel boilers leaked and had to have the joint caulked with a caulking chisel ( itís a flat ended blunt object )
Or they chucked a load of lime into the feed water
Title: Re: 3 inch boiler build
Post by: zeeprogrammer on July 21, 2018, 03:26:32 PM
Congrats Gary!

A couple of questions...

1) What's the purpose of the 1.5x test if a 2x test was done? Is the 2x for the boiler and the 1.5x for testing the rest of the system?
2) @Stuart "It is a known fact that a new boiler will not hold water but will steam.". Would you mind explaining that?
3) When I built my little 0-4-0 British Loco, they recommended distilled water. (That may be because the boiler was made from drain pipe.) What do you all use? (Tap water can vary greatly in hardness, etc.)
Title: Re: 3 inch boiler build
Post by: Stuart on July 21, 2018, 03:44:27 PM
Zee

Now boiler codes around the big ball vary

The 2x test is to test the structure of the boiler
That being passed the boiler is give a number stamped on the foundation ring
You then fit all the fitting ( the first 2x test is done with blanking plugs in the bushes except for the test rig) now you do the 1.5 with the fitting in place inc water gauge

That being ok
You then steam the boiler to its 1x or WP and set the safety valve/s as required this then is tested with a full glass full fire and full blower to test the safety valve/s to see if they control the pressure rise to less than 10%
Hope that has answered your question
Title: Re: 3 inch boiler build
Post by: Stuart on July 21, 2018, 03:49:56 PM
Boiler will not hold water but steam is ok

Now we are taking a small weep here

Because the boiler is cold the joints may not be perfect  but put some fire under it things expand and joints take up also the minerals in the water tend to block up tiny weeps

Not a boiler but temp related the black bird recon aircraft from your side of the pond leaked fuel like a colender on the runway at speed it got hot and was drum tight
Title: Re: 3 inch boiler build
Post by: Stuart on July 21, 2018, 03:54:56 PM
Zee
When I was fitt enough to ride on my locomotive and handle them in the workshop we used tap water , here and at the club it was of a fair quality , kettle descaler once in a while , but the injector cones needed a soak in citric acid a couple of times a year .

Note the boiler primed like crazy on the fist steam up after cleaning as does a new boiler due to the acid used and general muck in the shell
Title: Re: 3 inch boiler build
Post by: Jasonb on July 21, 2018, 04:09:45 PM
Yes you want to use reasonably clean water as overtime the impurities can hamper free steaming!

(http://i1133.photobucket.com/albums/m584/kscour/P1010389.jpg)

When it gets to that thickness you need a bit more than a flue brush to clean things out

(http://i1133.photobucket.com/albums/m584/kscour/P1010405.jpg)
Title: Re: 3 inch boiler build
Post by: zeeprogrammer on July 21, 2018, 04:13:37 PM
Thanks! Very helpful.  :ThumbsUp:
Title: Re: 3 inch boiler build
Post by: Stuart on July 21, 2018, 04:53:59 PM
Well Jason thatís just bad water testing/treatment

I have seen that sort of buildup in wet cooling tower ponds two things were found to be the trouble manager trying to save money by turning off the chemical dosing and second salt carryover from the ion exchange water softeners again said manager poking his nose in and reducing the rinse cycles both done without telling us he had done it
 :stir:
With ref to that boiler a quick dip in citric acid would have cleaned it up or fetch in ďblaster BatesĒ   :stir:
Title: Re: 3 inch boiler build
Post by: Gas_mantle on July 21, 2018, 08:52:36 PM
Great news Gary, I look forward to see it producing the hot stuff.

Better start thinking about buying some coal next  ;)
Title: Re: 3 inch boiler build
Post by: crueby on July 21, 2018, 09:36:15 PM
Congratulations Gary!!


 :whoohoo:
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 21, 2018, 10:02:12 PM
Thanks all for the good vibes!

I think that most of the questions raised in the above discussion have been answered, but if not please keep talking!

@ Peter - a couple of tons on order  ;)

@ Jason @Stuart - where I live the rock is granitic and the water very soft. No limescale inside our kettle year after year. Do you think I'll get away with tap water on that basis?

@ Jason - surprised you managed to remove that scale with a wimpish mini forklift arm. I would have thought you'd need one of these:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/808415.jpg)

 :)

gary
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 22, 2018, 12:10:13 AM
http://www.youtube.com/watch?v=7KjwgqLxTLA
Title: Re: 3 inch boiler build
Post by: Stuart on July 22, 2018, 05:59:07 AM
If itís that soft you will be ok ,you put more water though the kettle than you will though the boiler

Water facts
Distilled water is an electrical insulator and is use to wash down he insulators in service
Water is known as the universal solvent

Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 22, 2018, 07:43:39 AM
Yes, thanks Stuart. I thought so.

You are right - I drink 4 or 5 cups of tea every day - I don't see myself firing up the boiler that often  :)

Isn't water a conductor though? I was brought up to believe it to be a bad idea to drop a live electric fire into the bath when one is in it... :zap:  :)
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 22, 2018, 03:55:17 PM
Following an initial cleanup with files, Scotch-Brite and steel wool:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/808428.jpg)

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/808427.jpg)

gary
Title: Re: 3 inch boiler build
Post by: Stuart on July 22, 2018, 04:40:26 PM
Gary

Misconception distilled water is non conductive as it has no minerals in it , note I said distilled not softened or deionised  or put though a reverse osmosis plant

Itís the minerals that make it conductive , eg salt , soap as bath watta , one pinch of salt and itís conductive

That goes for storing it in a metal container all must plastic/glass

To add a note when they wash down the insulators they do push a earth on the nozzle


When I wxxked at the iron works were I did my time we had some large electrostatic preciperator for cleaning the blast furnace gas very dirty stuff in cyanide
But they washed them down with mains water whiles on 25-30 kv


Boiler looks great
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 22, 2018, 09:21:45 PM
Wow... I didn't know that. I always thought that water itself is conductive.

On the boiler - thank you Sir!
Title: Re: 3 inch boiler build
Post by: MMan on July 22, 2018, 10:36:32 PM
Yep, on water being an insulator. The arc furnace I worked on as a kid had water cooled electrode cables. The water came out of a treatment plant so was an insulator. I did idly wonder what a bag of chips would do if dropped in.

Martin.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on July 22, 2018, 10:42:23 PM
Ha... especially with extra salt and vinegar...!  :zap:
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on August 07, 2018, 10:20:36 PM
Hi guys -

progress has been slow as I've been away and the weather has been more conducive to alfresco beer and BBQ's than to workshop time   :DrinkPint:

However, I have just taken the black paint off all my fittings with acetone in favour of an all-brass look, and have made a start with Loctite threadlocker. My first experience with the stuff, but it does inspire confidence I have to say.

One slight issue faces me before I can go on to the second hydro test: way back when I was silver soldering in my bushes, I left brass blanking plugs (connected by a steel strip) in the two water gauge bushes in an attempt to keep them parallel. In my inexperience I didn't realise that the brass would be prone to melt, but the plug in the top bush did so. I had to drill it out and for reasons I can't now remember I ended up having to drill and tap it 5/16 instead of 1/4. I then made a threaded sleeve to reduce it back down to 1/4. This seemed ok, but tonight the sleeve sheared when I was trying it out. The upshot is that I'll have to make another one. I'm not overly worried about this as I'm pretty sure that with the Loctite it will be fine, but it's all more time of course...

Will keep chipping away and will post significant developments.

BTW you guys have been very kind and I'd like to return the courtesy by reading some more of your threads about your own work. It doesn't seem too easy to search for threads by author (am I missing something?), so if any of you would like to post a link here to your own favourite threads or just name them so I can search for them I'd be very grateful.

Cheers,

gary
Title: Re: 3 inch boiler build
Post by: Dan Rowe on August 07, 2018, 11:27:35 PM
It doesn't seem too easy to search for threads by author

Gary, if you go to any members profile page select 'show posts' then open the topics tab to show all the threads that member has started.

Dan
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on August 08, 2018, 06:35:16 AM
Aha - yes, thanks Dan. That works.

It seems immediately obvious now that you have explained it!

gary
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on August 14, 2018, 11:03:52 PM
Hi -

I've been trying out Stag Wellseal this evening on a few fittings:

https://www.heritagesteamsupplies.co.uk/gasket-sheet-jointing/jointing-compounds/wellseal.html (https://www.heritagesteamsupplies.co.uk/gasket-sheet-jointing/jointing-compounds/wellseal.html)

It's transparent, dark brown, runny and very sticky and looks for all the world like something chocolatey which you might squeeze on to an ice cream from a plastic bottle. You clean any grease from the mating threads (I used acetone), then anoint them with the Wellseal. You then leave them apart for about 5 minutes while the Wellseal thickens up, after which you either add a bit more Wellseal (if required) or just screw them together. Apparently it never really sets, so it's easy to remove the fittings if required and clean it off with a solvent.

I must admit that the stuff inspires confidence - it's so damn sticky!  It gets right into the threads and it's hard to imagine it not making an effective seal. However, the proof of the pudding will be in the testing. If it doesn't work I'll try one of the various Loctites, but for now I remain hopeful.

gary
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 02, 2018, 12:21:22 AM
Progress has been slow due to hot weather (barbie season) followed by a major renovation of our living room which is currently ongoing. However, I took today off and spent some time in the workshop.

Stan Bray (on whose design this boiler is based) has little to say about he configuration of the cap, smoke stack and steam stop and safety valves*, so I found myself having to figure it out myself. It was necessary to make extensions for the bushes on the top of the boiler so that the valves will sit above the cap. The first picture below shows the internal thread on one of them being tapped in round bronze bar in the lathe using a piloted spindle (which is a godsend - no more squint threads!):

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/810821.jpg)

I figured it would be easier to gauge the required heights for the extensions if I made the cap first. The photo below shows that the underside of the brass cap has a circular locating groove into which the top edge of the boiler fits. This was milled on my Dore Westbury Mk I using a rotary table. This is not the tidiest piece of milling in the world - a result of several issues which currently beset the mill (a situation which will be addressed in the near future...). It's not critical though as it won't be seen. You will also notice that the groove is a bit on the wide side - it's the size of the smallest endmill I currently have. Below you will see the cap (in which the hole for the smoke stack has not yet been made), the bush extensions, the cap retaining nuts (made from brass hex bar tapped M12), and the two valves:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/810820.jpg)

The last photo shows a trial fit of the unfinished cap assembly. Unfortunately the two valves are out of perpendicularity with the top of the boiler. This happened either at the end plate forming stage or while silver soldering. They look squint but there is nothing I can do about it now other than put the fiery flame on it again and that isn't going to happen. It's not perfect but it shouldn't affect the functionality and will be good enough given it's my first effort. It does however mean that there is a small gap between one side of each nut and the cap. To prevent combustion gases from escaping via that route I would like to close this using some kind of soft washer or gasket which would have to be heat-resistant. Any suggestions from you good people regarding what I should use for this would be welcome. In the photo you will also see that most of the fittings are now in situ. They are sealed (hopefully) with Wellseal. Not so far away now from the second hydro test at 1.5 wp...!  The picture shows the boiler in its current state sitting on the belt sanding attachment of my beloved Coronet Major woodturning lathe/all bells and whistles wood machining workstation:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/810819.jpg)

gary

* Edit 4/9/18: actually this isn't true. He does discuss it in his book, but there are aspects that I don't find very clear.
Title: Re: 3 inch boiler build
Post by: Gas_mantle on September 02, 2018, 12:42:22 PM
Taking shape nicely Gary, it ought to be steaming away shortly  :)
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 02, 2018, 01:01:25 PM
Cheers Peter!

 :ThumbsUp:
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 02, 2018, 10:14:31 PM
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/810900.jpg)

Taz says: 'How come the smoke stack is squint, Garyboy?'.

I say: 'Sorry Taz - It's because it's just rough cut and not soldered in yet. Just offered up for show'.

Taz says: 'Hmm. How come the valves on top of the boiler are squint then?'.

I say: 'Apologies, Lord Taz - the bushes in the boiler top plate somehow got misaligned and they are hard soldered in so I'm afraid it's a done deal, even if it looks a bit naff. They will still do the job though'.

Bad Boy Taz says: 'Ha. Aren't those top cap retaining nuts a bit big and out of scale for a model boiler?'.

I say: 'With respect, Your Highness, no. It's not a model boiler. It's a real boiler, albeit a tiny one, and I have this functionalist and you could say industrial aesthetic going on here. I'd even have preferred more utilitarian looking handwheels  or levers on the valves if I had the nous to make them myself'.

Taz looks disdainfully at me and says: 'Pretentious git. So how are you going to make decent seals in that groove under the cap and under those squint retaining nuts so that air doesn't get sucked in and combustion gases don't escape?

I say: 'I'm hoping the guys on the forum can recommend an appropriate heatproof gasket material, O Mighty One'.

Taz says: 'Right you are then. Meanwhile, feed me....'....
Title: Re: 3 inch boiler build
Post by: Kim on September 02, 2018, 10:52:07 PM
Sorry I can't help you answer Taz's important question, but I will say I enjoyed reading your conversation with Lord Taz!  :ROFL:
Kim
Title: Re: 3 inch boiler build
Post by: zeeprogrammer on September 02, 2018, 11:09:31 PM
My first suggestion might have something to do with removing a certain critic. He's tough!

In my book that's a fine looking boiler.  :ThumbsUp:
Title: Re: 3 inch boiler build
Post by: b.lindsey on September 03, 2018, 12:42:29 AM
It's coming together nicely Gary. Taz will come around and agree soon enough.

Bill
Title: Re: 3 inch boiler build
Post by: mikehinz on September 03, 2018, 01:09:22 AM
Lol!  We have a Siamese and I never let her into the garage when I'm working out there.  She's way too critical!  The Lab retriever on the other hand loves everything I do.  Go figure! 

From my perspective, excellent work! 

Mike
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 03, 2018, 12:44:38 PM
My first suggestion might have something to do with removing a certain critic. He's tough!

Carl - that would be my Inner Taz that you are referring to. You are right - he must go. As for the real world, fur and claws Taz depicted above, he is far too useful for keeping our old house free of mice   :)

Thanks to all of you for your comments - I feel encouraged!
Title: Re: 3 inch boiler build
Post by: Gas_mantle on September 03, 2018, 01:02:47 PM
Looks good Gary, next time you update your thread could you show a pic of the underside showing the tube arrangement etc.

Thanks  :)
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 03, 2018, 09:26:12 PM
Will do so Peter.

Cheers,

gary
Title: Re: 3 inch boiler build
Post by: Gas_mantle on September 03, 2018, 09:48:22 PM
Thanks, any thoughts on what engine you will build first? You can't have a boiler with nothing for it to do  ;)
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 03, 2018, 10:35:20 PM
True!

I plan to start with a simple single-acting oscillator of about 1" bore. My thought is to make this out of bar stock and keep it as rectilinear as possible just to get started. I'm thinking perhaps of going with plans by Andrew Smith or Steve's Workshop but upping the size a bit.

After that I might be looking at another similar engine (or a double-acting equivalent if I feel confident) but made from my own castings in aluminium and/or brass from my home-built furnace. At this point I might think about getting funky with the shapes to make them look interesting:

HlolkvQ7rQs
After that - assuming I haven't thrown down my tools in despair by then - I could perhaps move on to a mill-type engine such as Andrew Smith's Vulcan or a version thereof. This could be made from a combination of bar stock and my own castings and again I might aim for a 'different' look. Making the valve, eccentric and so on will of course be a major step up and challenge.

Then - if I live long enough - I'll turn to the PM Research #6 kit of castings which is sitting on my shelf even now. I'm assuming that by that point I'll be competent enough not to destroy the castings. It will also require a bigger boiler than the one I'm building now... I might have to either bite the financial bullet and buy a Castle Steam V6 or build something equivalent  ;)

That's my path mapped out from my present vantage point, Peter. It could of course all change. I plan to build an astronomical telescope too (6 inch F15 refractor), but steam engines have jumped the queue and I'm absolutely determined to keep going with them until I see at least one flywheel (and hopefully more than one) spinning on live steam!

That's my best-laid plan. We shall see...

gary

 

Title: Re: 3 inch boiler build
Post by: Kim on September 03, 2018, 10:48:18 PM
That's my path mapped out from my present vantage point, Peter. It could of course all change. I plan to build an astronomical telescope too (6 inch F15 refractor), but steam engines have jumped the queue and I'm absolutely determined to keep going with them until I see at least one flywheel (and hopefully more than one) spinning on live steam!

Cool!  An refractor scope?  I've built a couple of reflectors (a 4" and a 10", and was attempting to grind my own 8" mirror (never got far on that))  But a refractor - that's another thing completely.  Are you planning to grind your own lenses?

Definitely don't want to change your priorities here though!  I'd stick with steam :)  Just thought that was pretty interesting comment!
Kim
Title: Re: 3 inch boiler build
Post by: zeeprogrammer on September 03, 2018, 10:50:36 PM
After that - assuming I haven't thrown down my tools in despair by then -

That won't happen. You have the bug.  ;D
If it helps, just take a look at my bonehead boo-boos.
In my few years in this hobby, I feel I have the record on 'huh?", "wha?", size of 'wall of learning' and  :cussing:. Not to mention "rats rats and rats".
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 03, 2018, 11:20:00 PM
@ Kim - a shared interest! I already have the objective for the refractor. It's an Istar 6 inch F15 achromatic which has been sitting on my shelf for a good while now. I can't wait to get to work on it. Would love one day to build a big Dobsonian too. I need to split into parallel lives to fit it all in.
Bet your ten inch reflector opens up some deep space beauty though...

@ Carl - yep. You are right. The bug has bitten. Regarding mistakes - they are always there, waiting for any random moment of inattention or complacency in which to pounce. And I have noticed that they especially love to take advantage of moments of pride or self-congratulation. Apparently one can learn from them...    ;)
Title: Re: 3 inch boiler build
Post by: Gas_mantle on September 03, 2018, 11:25:48 PM
That's a coincidence, I have a 5" refractor on a goto NEQ6 mount but it rarely gets used these days and I have considered selling it.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 03, 2018, 11:35:03 PM
Aha!

Birds of a feather once again...

I also have a 5" refractor - a Bresser Messier. It's on a Skywatcher AZ4 mount - nice and easy. Quite a good setup overall. I also have a couple of small scopes with goto (Orion ST-80 and a Skywatcher 90 mm Maksutov), and an 8 inch reflector. The reflector gives good views but  is a pig to lug around and set up, hence:

k-S7HB6F9Z8t=4s

gary
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 04, 2018, 09:58:51 PM
Well, back to sealing the smokebox, then.

I went to a local suppliers and found this:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/811062.jpg)

It's carbon gasket material, rated at 500 degrees centigrade. I reckon that will do! The stuff is very expensive but he had an offcut which cost me a fiver. It's plain black on the other side, and surprisingly easy to work. I scribed it with dividers, cut it with scissors, drilled it, and cleaned up the edges as best I could on a small drum sander chucked in the drill press. All very easy. Here's the finished set:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/811060.jpg)

Here are the top gaskets in situ:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/811059.jpg)

And here's the one under the cap, viewed from below:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/811063.jpg)

The gaps appear to be closed and I have no reason at this stage to think it won't do the job.

When I was cutting the bush extensions to height, I forgot to take into account the thickness of the gaskets. This turned out to be a blessing in disguise because rather than make new extensions I just skimmed the nuts down to size in the lathe, making them look slimmer and (imho) better.

gary
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 04, 2018, 10:35:07 PM
Looks good Gary, next time you update your thread could you show a pic of the underside showing the tube arrangement etc.

Thanks  :)

Peter -

as requested, here is the underside of the boiler:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/811068.jpg)

You'll notice that the tubes are spaced not in a square but a rectangular pattern. I did this to make sure that I left enough room for the bushes at the top, but in Stan Bray's original plan the four tubes are arranged in a square. My boiler is a 1.5 scale version of Stan Bray's. Here is the plan for it from his book:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/811069.jpg)

(If Stan happens to be a member of this forum, please let me reassure him that I have no wish to breach copyright and I have no doubt that anyone wishing to build a version of his boiler will want to buy the book, here: https://www.amazon.co.uk/Making-Simple-Model-Steam-Engines/dp/1861267738/ref=asap_bc?ie=UTF8 (https://www.amazon.co.uk/Making-Simple-Model-Steam-Engines/dp/1861267738/ref=asap_bc?ie=UTF8))

Because my boiler is 3 inch diameter, not 2 inch, I had to approximate to the scaled-up dimensions of the tubes etc as best I could from what was available. Peter, I think I sent you these dimensions before, but if you can't find them let me know and I will resend.

BTW I said in an earlier post that Stan Bray 'has little to say (in the book) about the configuration of the cap, valves etc'. From the above picture you will see that in fact he does in fact go into this, but in my opinion he doesn't give particularly clear information on what happens to the smoke from the auxiliary tubes. Not to worry, though...

Hope that's helpful.

gary

Title: Re: 3 inch boiler build
Post by: Gas_mantle on September 04, 2018, 10:44:30 PM
Thanks Gary, its coming along nicely  :)
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 04, 2018, 11:02:37 PM
 :ThumbsUp:
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 08, 2018, 12:19:23 AM
A slight digression today:

QKOnQ9_itmQ
Title: Re: 3 inch boiler build
Post by: zeeprogrammer on September 08, 2018, 01:36:24 AM
 :ThumbsUp:

I remember when I got my face mill...with my new mill...it was a joy.

Machines. Just have to love machines.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 08, 2018, 10:09:46 AM
Carl - Yay!!! to all of that.

So looking forward to face milling...  :cartwheel:
Title: Re: 3 inch boiler build
Post by: Jasonb on September 08, 2018, 01:26:04 PM
Enjoy your new toy.

I'd be interested on how you get on with that face mill, out of the box the one I got from Bangood was pants, now I have sorted it out it performs quite well as a face cutter but won't give a 90deg angle if working to an edge like it should.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 08, 2018, 05:50:33 PM
Thank you Jason - I'll do my best   :)

Not so great on the facemill though. What did you do to sort it out?

I also have another question for you: does that power feed that Axminster sell overhang the back of the table, and if so by how much?
Title: Re: 3 inch boiler build
Post by: Jasonb on September 08, 2018, 08:30:52 PM
Two main issues with the facemill. Firstly the head was a loose fit on the arbor so was running out of true and secondly the supplied tips and also an extra box of 10 that I ordered at the same time were not that sharp even for carbide. Once the run out was sorted and some decent tips fitted it cut a lot better. All in this thread over on ME

https://www.model-engineer.co.uk/forums/postings.asp?th=135611&p=1

Will have a measure of the feed tomorrow morning and see where it is likely to come, the same feed unit fits several of the Sieg machines but comes with different adaptors depending on which model mill you have. It fits my X3 with the DRO scale on the back but I don't have an excessively over length scale.
Title: Re: 3 inch boiler build
Post by: Jasonb on September 08, 2018, 08:46:51 PM
Just looking through the latest Sieg catalogue and they list different feed units for the standard and Long tables. I think Axminster only do it for the standard table as they don't do the long bed machine.

http://www.siegind.com/Application/Home/View/demo_ximate/pdf/SIEG.pdf
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 09, 2018, 08:41:19 AM
Two main issues with the facemill. Firstly the head was a loose fit on the arbor so was running out of true and secondly the supplied tips and also an extra box of 10 that I ordered at the same time were not that sharp even for carbide. Once the run out was sorted and some decent tips fitted it cut a lot better. All in this thread over on ME

https://www.model-engineer.co.uk/forums/postings.asp?th=135611&p=1


That doesn't sound great! I don't doubt Doubleboost's integrity, so maybe he was just lucky, or (more likely) Banggood made sure they sent him a good one, or perhaps you were just unlucky... :???:

I'll check mine out sometime soon. Have had a look at the thread you linked to; will read it more thoroughly soon. I did notice a photo of a beautiful piece of machining by yourself in the thread.

Thanks,

gary



Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 09, 2018, 08:51:41 AM
Just looking through the latest Sieg catalogue and they list different feed units for the standard and Long tables. I think Axminster only do it for the standard table as they don't do the long bed machine.

http://www.siegind.com/Application/Home/View/demo_ximate/pdf/SIEG.pdf

Wow... you are correct. I'm glad you flagged that up, otherwise it might have been an expensive mistake!

Doesn't look like one can order direct from Sieg. I may not go down the power feed route anyway, just weighing up possibilities. Probably best to fit the DRO then see what I'm left with.

Cheers,

gary
Title: Re: 3 inch boiler build
Post by: Jasonb on September 09, 2018, 01:35:35 PM
Bangood are not a supplier like Chronos. RDg, ARC etc but just a market place like e-bay, Amazon, etc so you are not always going to get exactly the same item as they list quite a few 50mm face cutters. Depending on where they actually come from they may be rejects sold on at a discount, walked out the back door in someones lunchbox or reasonable ones sold at a low price for various "money" reasons. So it is a bit pot luck what you get. I was not given mine so happy to say what it was actually like.

The Feed unit is narrower than the 2.7 table and the adaptor blocks that house the clutch all seem to be made to the table width and replace the black end plate so should not stick out beyund the back edge.

I don't know why the long table should need a different unit, if you do decide you want one Ketan may be able to special order for you but Sieg are on a long delivery leadin time at the moment.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 09, 2018, 02:18:27 PM
Jason -

Yes. I'm going to put a clock on my facemill as soon as I get a chance (painting hallway this morning, out with daughter this afternoon...you know how it goes) and take a couple of trial cuts. And then there's these 'blue nano' cutters with it...
Will post here on how it goes.

If I do decide to check out the power feed more fully I'll have a chat with Arc about it as you suggest.

Again - thank you.

gary
Title: Re: 3 inch boiler build
Post by: propforward on September 09, 2018, 02:41:42 PM
That's a nice new mill Gary. Similar to my import mill. I found I had to do some measuring and set up on both my lathe and mill to get them square, trammed and true, but after that bit of effort, plenty good machines. Looking forward to seeing you make chips with it.

The face mill is an excellent idea, I'll keep that in mind, I may well want one of those.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 09, 2018, 08:42:34 PM
Cheers Stuart   :)

Will check it for tram soon. I'm sure it will feature in future postings...
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 09, 2018, 09:32:49 PM

The face mill is an excellent idea, I'll keep that in mind, I may well want one of those.

Stuart - I haven't tried the facemill yet but if by any chance you are thinking of buying one from Banggood, see Jason's comments higher up in this thread.

gary
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 10, 2018, 10:20:44 PM
Jason -

Yes. I'm going to put a clock on my facemill as soon as I get a chance (painting hallway this morning, out with daughter this afternoon...you know how it goes) and take a couple of trial cuts. And then there's these 'blue nano' cutters with it...
Will post here on how it goes.

Some numbers:

Spindle runout on new Sieg SX2.7L:       0.01 mm

Runout on R8 arbour of Banggood facemill    0.03 mm

Runout on head of Banggood facemill:       0.06 mm

Haven't fitted the cutters yet, so no info so far on how it performs...
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 18, 2018, 10:53:26 PM
A little bit of progress this evening after a major episode of DIY in the house.

All fittings (apart from the safety valve and the steam pressure gauge) are now in situ for the second hydraulic test at 1.5 x working pressure:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/812167.jpg)

Apologies for the somewhat fuzzy picture. I'll carry out the test at the weekend. The cap and chimney are not yet silver soldered together - the chimney is resting in a circular rebate which I cut around the central hole to approximately half the thickness of the cap. My idea is to give the silver solder somewhere to flow into. Any advice anyone can offer on how to silver solder brass without ruining it will be most welcome!

The photo below shows a close-up of the water level gauge. Fitting it was easier than I expected, though I won't get too cocky until I have seen it not leaking under pressure. I had to make a 1/4" to 5/16" adaptor for the top bush due to a mishap back when I was silver soldering the boiler. It seemed to work ok, but time will tell.

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/812166.jpg)

gary
Title: Re: 3 inch boiler build
Post by: Gas_mantle on September 18, 2018, 11:06:49 PM
Looking good Gary, the water gauge looks to be a better quality one than is often seen on small boilers.

Don't forget to update us on how the pressure test goes  :)
Title: Re: 3 inch boiler build
Post by: zeeprogrammer on September 18, 2018, 11:43:04 PM
I have a boiler kit waiting in the wings. I hesitate to work on it because I know so little about them (and they are bit dangerous).
The water gauge for example is something that I've always wondered about.
The glass is under the same pressure as the boiler, right? Or not?

I don't mean to hijack your thread, Gary. Your thread...like many other members' threads is excellent learning for me.
Title: Re: 3 inch boiler build
Post by: Gas_mantle on September 18, 2018, 11:46:48 PM
I have a boiler kit waiting in the wings.

Carl, which kit is it that you have? I want to try and make a small boiler before long, I was intending to use 3" dia copper tube that I already have but have considered building from a kit.
Title: Re: 3 inch boiler build
Post by: zeeprogrammer on September 18, 2018, 11:48:37 PM
It's the BLR-1 from PMR.

Another reason for the hesitation...I kind of like/prefer the horizontal boilers. So it's been difficult getting excited about this one.
Title: Re: 3 inch boiler build
Post by: Gas_mantle on September 18, 2018, 11:55:31 PM
Cheers Carl, I kinda quite like that little boiler and have thought about buying one. The thing that puts me off is it has quite a lot of tubes and looks a bit of a challenge to someone new to boiler building. I'd like to try something with only a few tubes first  :)
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 18, 2018, 11:59:32 PM
Thanks both.

@ Peter - yeah, I decided to go for it with the water gauge and get a nice one (which is also regulation compliant). It cost me more than I wanted to spend...  ;)

I will indeed report on the test.


@ Carl - although one of course has to treat boilers with respect, I have learned that there is a sequence of tests which - as long as one follows it - makes any nasty surprises unlikely. If you follow the recognised protocols and use common sense it should be safe enough. I hope.

Yes, the water gauge glass takes the same pressure as everything else in the system. It looks and feels flimsy, but that's what it's designed to do...

Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 19, 2018, 12:01:02 AM
Cheers Carl, I kinda quite like that little boiler and have thought about buying one. The thing that puts me off is it has quite a lot of tubes and looks a bit of a challenge to someone new to boiler building. I'd like to try something with only a few tubes first  :)

Thing is though Peter - if it doesn't have many tubes you might struggle to run it on coal...   ;)
Title: Re: 3 inch boiler build
Post by: Gas_mantle on September 19, 2018, 12:02:47 AM

Thing is though Peter - if it doesn't have many tubes you might struggle to run it on coal...   ;)

I was hoping you were going to buy my coal  :Lol:
Title: Re: 3 inch boiler build
Post by: zeeprogrammer on September 19, 2018, 12:58:12 AM
@Peter...I'm not sure that boiler kit is too much of a challenge. A lot of people have done that model. Marv will also have some insight. Having said that...it's the soldering that concerns me. I don't have much experience and worse...I don't really know what equipment (burner) I need to accomplish it.

@Gary...Quite true regarding respect. It's all in the testing. But boy that water glass is a little concerning.  ;D
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 19, 2018, 06:42:50 AM

Thing is though Peter - if it doesn't have many tubes you might struggle to run it on coal...   ;)

I was hoping you were going to buy my coal  :Lol:

@Peter - you never know - you might end up using it yourself  :)

@ Carl - from my own limited experience, you are right - the biggest challenge is in the silver soldering, which unfortunately a kit would not preclude. You need a powerful propane torch such as a Seivert or similar - a DIY blowtorch isn't powerful enough.

Will report on the second water test at the weekend. Skimpy as the glass seems to be (like a glass straw really), my main concern at the moment is the top bushing with its thread adaptor 'repair'. I'm hopeful, though, as it passed the first hydro test fitted with a blanking plug...
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 19, 2018, 06:47:14 AM
I have a boiler kit waiting in the wings. I hesitate to work on it because I know so little about them (and they are bit dangerous).
The water gauge for example is something that I've always wondered about.
The glass is under the same pressure as the boiler, right? Or not?

I don't mean to hijack your thread, Gary. Your thread...like many other members' threads is excellent learning for me.

Carl - no worries - I don't feel hijacked at all  :ThumbsUp:
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 25, 2018, 12:08:43 AM

The photo below shows a close-up of the water level gauge. Fitting it was easier than I expected, though I won't get too cocky until I have seen it not leaking under pressure.
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/812166.jpg)


Ha. So much for that.

The second water pressure test confirmed that the boiler itself is intact and that all fittings are leakproof where they are screwed into the bushes in the boiler.

However, I could not get the water gauge itself to stop leaking where the glass tube meets the fittings. The fittings don't look particularly out of alignment but in my inexperience I have no knowledge of the relevant tolerances. The rubber o-rings are unforgivingly small and skimpy and during my repeated efforts to banish the leaks I shredded them and could find no suitable replacement in my shop.

It gets worse. In my desperation I thought I'd see if putting PTFE tape under the union nuts would do the job. When I was was tightening the bottom union nut I cross-threaded it, ruining the threads. I wish it had been the threads on the nut that I ruined, but it wasn't - it was the threads on the bottom fitting of the very expensive three-cock water gauge. The threaded section looks like it is silver soldered into the fitting and is probably too short to re-thread with a die. This looks to be a costly bit of carelessness on my part as it looks like I'll have to buy a new gauge (or at least the bottom fitting if anyone will sell me one).

But if this is due to a slight misalignment of the fittings, who's to say this won't happen again with new parts?

One thing that may help is this: https://www.glrkennions.co.uk/silicon-tube.html
It looks like it can be used instead of o-rings and it might be a bit more forgiving. I'll give them a ring in the morning.

The annoying thing about this is that with the cocks on the gauge closed off, even without the glass installed, the boiler now sits happily at 1.5 x working pressure until the cows come home. I was hoping to be on to the steam test this week but instead it's more money, more delay and more uncertainty...    :headscratch:

If any of you knowledgeable people have any advice to offer on this I will of course be delighted to hear it...

gary

Title: Re: 3 inch boiler build
Post by: Gas_mantle on September 25, 2018, 12:35:21 AM
Gary.

Sorry to hear you've hit a snag, but on a positive note the pressure vessel sounds to be fine and the fitting should be a fairly easy fix.

If you are using the 'O' rings that came with the gauge you'd expect them to fit but even so replacements are easy enough to buy. I'm no expert but I'd expect there is just a bit of poor fit/misalignment somewhere. I'd be inclined to just order a few more 'O' rings and give it another try before doing anything else.

I'm not entirely sure where you mean you have stripped the threads, can you explain a bit more?  Assuming you mean you have stripped threads outside of the 'pressure circuit' then it should be fairly easy to fix even if it involves making and soldering a new part.

Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 25, 2018, 12:56:35 AM
Peter -

Yes, the pressure vessel appears to be sound now and that's the main thing.

I'll certainly order some more o-rings as well of some of that silicone tube and see if I can sort out the gauge. However, I can't do that until the new problem of the damaged threads is resolved.

Look at the photo above. At the bottom end of the glass tube there is a union nut. It's the threads on the actual fitting that the union nut screws on to that are damaged. Part of the 'pressure circuit', unfortunately. The nut will not now go on straight. There isn't enough length in the threaded part to fix with a die and it's probably too knackered anyway. Also, the threaded part appears to be hard soldered into the fitting, and the fitting is very precisely made - probably too precise for me to attempt at this point. It involves two of the valves. I'll have another look at it tomorrow but even if it turns out to be something I could make, I might prefer to bite the bullet and shell out for it rather than get sidetracked into it at this point. One option is I could buy a standard pressure gauge which would be cheaper, but we'll see.

Could have lived without this at this point but there we are...
Title: Re: 3 inch boiler build
Post by: Gas_mantle on September 25, 2018, 01:02:44 AM
I see what you mean about the union nut now.

While waiting for replacement rings maybe it's worth removing the damaged parts and showing them in close up in the hope someone can suggest a repair?
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 25, 2018, 01:09:29 AM
Good idea Peter.

Will do that tomorrow...
Title: Re: 3 inch boiler build
Post by: Jasonb on September 25, 2018, 07:15:47 AM
When fitting the top and bottom halves take the blanking plug out of the top fitting and pass a rod down through it and into the bottom fitting, this should help check that you have them lined up correctly, it wants to be a close fit in them. And will probably have to be turned or a drill bit shank may do.

Just a thought on the sealing, have you got 3/16" tube in a 5mm fitting?
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 25, 2018, 10:34:13 AM
Thanks Jason.

I was aware of the principle of checking with a rod, but in my hubris I decided that I could just check it with the glass itself. This proved to be an expensive mistake as it indirectly led to the thread on the fitting getting totally buggered up. I have just cut my losses and ordered a new gauge. Plus extra glass and o-rings. Ouch...

I should know better than to ignore established practice which is easily available online.

Next time, the rod (or drill bit)...

It occurs to me that knowing the tolerances in any situation is a big part of this. Even, for example, how much torque a brass blanking plug will stand before it shears. As a beginner I am slowly learning this stuff, sometimes (as in this instance) the hard way.

The glass came with the gauge - both are 5 mm.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 25, 2018, 10:41:51 AM
BTW the lady at Blackgates Engineering tells me that it's a good idea to use two o-rings at each end of the glass (i.e. four altogether). She says it makes a better seal.
Title: Re: 3 inch boiler build
Post by: Tennessee Whiskey on September 25, 2018, 01:55:06 PM
Sounds like a bit of bad luck Gary. Well they say education is expensive no matter how you get it  :facepalm:  Keith Appleton has some really good videos on model boiler fittings and such, if should want to have a look. I feel success for you this time

Whiskey
Title: Re: 3 inch boiler build
Post by: michaelr on September 25, 2018, 04:26:25 PM
With a suitable O ring or a twist of PTFE tape your gauge glass nuts need only be finger tightened or a very little over, to tight will damage the O ring any little weep will probably self seal when the boiler is in steam, this is the method I used on my gauge glass when I was running my traction engines. 


Mike
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 25, 2018, 04:31:46 PM
Well they say education is expensive no matter how you get it  :facepalm: 
Whiskey

Very well put, Whiskey, and so true  :Lol:

Thank you Sir.

I have in fact watched Keith Appleton on installing a water gauge, but somehow I didn't take on board just how carefully the alignment needs to be checked. Or maybe it was something else that I didn't get right, like the adjustment of the various screws...

In any case - lesson learned!

It's getting there overall, but the devil is in the detail...  :mischief:
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 25, 2018, 04:33:14 PM
With a suitable O ring or a twist of PTFE tape your gauge glass nuts need only be finger tightened or a very little over, to tight will damage the O ring any little weep will probably self seal when the boiler is in steam, this is the method I used on my gauge glass when I was running my traction engines. 


Mike

That is very useful information.  Overtightenng the nuts was definitely one of my errors last night.

 Thanks Mike.

gary
Title: Re: 3 inch boiler build
Post by: zeeprogrammer on September 30, 2018, 04:22:12 PM
Just catching up. Very sorry to see about the snag.

Be assured...it's not just you gaining knowledge. This is a very helpful to me and others.
I had no idea about using a rod or doubling up on o-rings.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 30, 2018, 10:24:50 PM
Cheers Carl.

I'm sure the snag isn't insurmountable...  :thinking:

Great to know you are finding this thread helpful. Indeed, before  started it I scoured the net for the kind of info that has subsequently appeared on it and found very little.

If this thread becomes any kind of a one stop shop for neophyte boiler builders, then I am happy. As you suggest, the level of expertise which is generously shared on this forum is second to none.

BTW am currently reading your Popcorn Engine thread right through. It's a great read and again a fabulous learning resource  :ThumbsUp:

Cheers,

g



Title: Re: 3 inch boiler build
Post by: Gas_mantle on September 30, 2018, 10:33:51 PM
In a fit of madness I've just bought a 3" horizontal boiler on ebay. It's untested but I'm a member of a club so should be able to get it checked and get a bit of advice etc. I didn't pay a lot so I thought it worth a gamble  ;)
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 30, 2018, 10:34:44 PM
While I am waiting for the replacement water level gauge I thought I might as well lick my wounds and progress with other aspects.

Today I silver soldered the chimney on to the boiler cap. I was worried that I might melt the brass, so I used a low temp silver solder and my small oxy-mapp kit instead of the Sievert Thermobaric Uberblaster.

It worked fine and the brass didn't flinch, as hopefully the photos below illustrate:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/813018.jpg)

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/813019.jpg)

Title: Re: 3 inch boiler build
Post by: gary.a.ayres on September 30, 2018, 10:46:34 PM
In a fit of madness I've just bought a 3" horizontal boiler on ebay. It's untested but I'm a member of a club so should be able to get it checked and get a bit of advice etc. I didn't pay a lot so I thought it worth a gamble  ;)

Nothing ventured, nothing gained, Peter. No reason to assume it isn't a viable boiler, and at least on ebay there is some recourse if someone sells you a lemon.

Best of luck, and I look forward to the updates!
Title: Re: 3 inch boiler build
Post by: propforward on September 30, 2018, 11:32:00 PM
Chimney looks great - lovely job on the soldering!
Title: Re: 3 inch boiler build
Post by: Steamer5 on October 01, 2018, 04:13:50 AM
Hi Gary,
 A bit late to the party, nice looking boiler. On the gauge glass o-ring front, canít remember why I did it, likely they were the only id o-rings I could get to fit the glass, but the od was either very tight or didnít fit the nuts, so I got a bit of rod a bit, & I mean just a bit over the id, put more than required rings on it ( was doing this for 2 gauge glasses) & carefully turned the rings down so that they just fitted into the nut. So far Iíve had no problems with leaks & the extras are carefully tucked away. Doing this means you can use a bigger diameter /thicker o-ring. Hope this may be of help.

Cheers Kerrin
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on October 01, 2018, 09:48:34 AM
@ Stuart - thank you  :)

@ Kerrin - On my previous, failed effort I think I found that the o-rings were too thin, rather than too thick to go inside the nuts. That's why this time (when it arrives) I'm thinking of using two at each end, rather than one. Also, this time I'll follow Mike's advice above and not over-tighten the nuts. If I have understood you correctly it seems that maybe my issue here is different from the one you describe. However, if I'm still struggling after my second attempt I may come back to you on this. Cheers  :ThumbsUp:
Title: Re: 3 inch boiler build
Post by: Steamer5 on October 02, 2018, 05:42:50 AM
Hi Gary,
No problem. Currently on holiday so canít check out the size I used, or the gauge glass size.....pretty sure the glasses are 5mm. As to the nuts yep finger tight.

Cheers Kerrin
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on October 02, 2018, 09:40:39 AM
Thanks Kerrin.

Am hoping the new gauge will arrive today. Will report back here on how it goes.

Enjoy your holiday!
Title: Re: 3 inch boiler build
Post by: Gas_mantle on October 02, 2018, 02:32:04 PM

Am hoping the new gauge will arrive today. Will report back here on how it goes.


This time don't put a scaffolding pipe over the end of the spanner when you tighten the nuts  :Lol:
Title: Re: 3 inch boiler build
Post by: crueby on October 02, 2018, 03:15:26 PM

Am hoping the new gauge will arrive today. Will report back here on how it goes.


This time don't put a scaffolding pipe over the end of the spanner when you tighten the nuts  :Lol:
I had to do that once to get a stuck lug nut off a car with a flat - worked, but not recommended!  ::)
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on October 02, 2018, 10:17:17 PM
This time don't put a scaffolding pipe over the end of the spanner when you tighten the nuts  :Lol:

Well, Peter - funny you should say that, because with the replacement water gauge I also ordered some tiny laser-cut spanners from Blackgates Engineering:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/813125.jpg)

They have already paid for themselves, and no scaffolding poles required. The test pressure gauge sat pretty at 1.5 x WP with the water gauge installed:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/813126.jpg)

No leaks!


And so - at last - on to the first steam test, for which I will use a gas flame.

 :cartwheel:
Title: Re: 3 inch boiler build
Post by: propforward on October 02, 2018, 10:22:35 PM
Great progress! It will be great fun to make steam.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on October 02, 2018, 10:27:45 PM
It will be, Stuart.

Pure alchemy. Magic!
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on October 06, 2018, 01:19:40 AM
 :cartwheel: :cartwheel: :cartwheel: Yaaaay! The culmination of months of angst! A great day!!!   :cartwheel: :cartwheel: :cartwheel:

First steam test today, and I couldn't have asked for better!

No leaks, and spectacular, surprisingly powerful whooshes of live steam when the safety valve blew off and when I opened the steam out valve!

The picture below doesn't capture the energy of  that, but it does show the boiler ( with all its fittings) sitting on a firebrick-shielded outdoor gas ring, firing up:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/813365.jpg)

Only one (inevitable) fly in the ointment - due to an operating system 'upgrade' my video editing program is malfunctioning so I couldn't post the videos I shot. Will get on to that over the weekend though, and post here when it's sorted.

Anyway, no matter - a major staging post has been reached and I can now go on to getting creative with trying out different heat sources and firebox configurations.

Couldn't have done this without you guys - thank you so much   :LittleAngel:
Title: Re: 3 inch boiler build
Post by: Ye-Ole Steam Dude on October 06, 2018, 01:51:31 AM
Congratulations on the steam up and a nice looking boiler.

Have a great day,
Thomas
Title: Re: 3 inch boiler build
Post by: Gas_mantle on October 06, 2018, 10:00:17 AM
Great stuff Gary - well done  :)

I look forward to seeing a video of it operating.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on October 06, 2018, 10:59:25 PM
Thanks both.

@ Thomas - nice of you to look in - will return the compliment.

@ Peter - cheers  :ThumbsUp:

Due to ongoing software conundrums the video is not of the best quality but it does show the boiler doing its stuff, below:

W1LxeZmfeBIt=249s

Title: Re: 3 inch boiler build
Post by: Gas_mantle on October 08, 2018, 05:28:01 PM
Gary, I don't know about anyone else but I can't see the video  :(
Title: Re: 3 inch boiler build
Post by: Kim on October 08, 2018, 05:38:06 PM
Gary,
I think you have to leave the [ youtube ] [/ youtube] brackets out when you put in a Youtube link these days, otherwise it doesn't work on IE.  I don't know why. So just paste the link in w/o the Youtube brackets and everyone should see the video.
Kim

This should work for IE and Chrome users:
W1LxeZmfeBI
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on October 08, 2018, 05:45:03 PM
Many thanks both.

Kim - I use Firefox and could see the video in my post before. However, I have now followed your suggestion.

Does it work now?

gary
Title: Re: 3 inch boiler build
Post by: Gas_mantle on October 08, 2018, 05:53:14 PM
Thanks guys, I can see it now  :)

Super job Gary it looks and performs great, I look forward to seeing it power an engine.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on October 08, 2018, 06:06:23 PM
Peter -

Thanks for your unfailing interest and support in this.

It's much appreciated.

gary
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on October 10, 2018, 12:10:41 AM
I did a test firing with methylated spirits this morning. It seemed to go quite well:

9QwzpgftKict=2s
Title: Re: 3 inch boiler build
Post by: MJM460 on October 10, 2018, 08:00:15 AM
Hi Gary, well done on another successful test firing.

I am with you on keeping it simple, and Meths is a very safe fuel for our purposes.  It only takes water to extinguish it, unlike other liquid fuels and much safer than gas.  So no need to feel it is second rate.  I would also suggest a separate fuel tank with a plug and a small diameter vent and a tube to the base of a burner which has your wicks.  If the tank in that enclosure gets to hot, you will get a big flare up when the meths boils (at about 93 C).  Wick tubes need to be high enough to prevent the Meths overflowing the burner.  It's not such an issue with a Mamod or similar as they only contain about 30 ml of fuel.  It looks like you had much more than that, and it could go for a long time.

That licking around the edge is inevitable while you have that gap.  Less air flow resistance that way than up the stack, though as it all heats up, some draft helps the flow through the flue tubes. When the boiler sits on a fitted firebox, it won't happen.

You may have to experiment with a bit bigger air entry to your burner casing, perhaps with a sliding cover to allow you to vary it to get a good looking flame.

Some insulation will help, cork is easy once you have the flame contained.

For measurements, I suggest a digital scale, reading to 1 g, as more accurate than level observations.  Just measure before light up, then again after it has cooled.  If your scale will accomodate the whole boiler without burner, you can determine the steam generated during the steaming time, though the total weight may exceed your scale once you have an engine connected.

You should be able to do a longer steam test by adjusting the steam valve to keep the pressure about constant and below the safety valve setting.  And obviously also keep an eye on the water level.  The boiler does not know if the steam goes to an engine or just to atmosphere.  It's worth experimenting to see how much fuel can be used without running the boiler water too low unless you intend to keep topping up water with your hand pump.

Again, well done on another good test.  It has been good to follow your progress.

MJM460
Title: Re: 3 inch boiler build
Post by: Gas_mantle on October 10, 2018, 09:38:41 AM
Nice one Gary,

It seems to be very effective on meths, my guess is the yellowish flame is just down to some residual contamination left in the tin, the situation will likely improve once you have made a better vessel. You may even find if the flame burns better you will get more heat and be able to reduce boil time.

Peter :)
Title: Re: 3 inch boiler build
Post by: Ye-Ole Steam Dude on October 10, 2018, 10:06:38 AM
Hello Gary,

Very impressive and a job well done.

Have a great day,
Thomas
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on October 10, 2018, 12:25:16 PM
Thank you all three   :)

@ MJM460 - lots of good information and advice there for me to consider. Am pleased that meths isn't considered second-rate - firing the boiler on it gave me a good feeling! Interesting point about that gap between burner and boiler - I think it warrants further exploration... though I'll probably aim to close it once the thing is properly assembled.
On the burner casing - yes, I have several modifications in mind for this - the way it is presently is just a start.
Good idea re a more controlled steam test. I had assumed that I'd need the pump connected up for that (which it will be, but isn't permanently connected yet), but I can see now that that isn't strictly necessary as long as the water level is kept an eye on.

@ Peter - will keep an eye on th flame colour. Indeed, the flame seemed clean enough, albeit yellow in colour. Very little soot was formed.

@ Thomas - cheers  :ThumbsUp:
Title: Re: 3 inch boiler build
Post by: Kim on October 10, 2018, 02:36:17 PM
Very interesting test, Gary!
Thanks for sharing your experiment.
Kim
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on October 10, 2018, 05:42:03 PM
Cheers Kim, and thank you for your interest.

gary

 :ThumbsUp:
Title: Re: 3 inch boiler build
Post by: MJM460 on October 11, 2018, 12:03:22 AM
Hi Gary, the heating value of Meths is about 26000kJ/kg, only about half that of other hydrocarbon fuels such as propane and butane, so you have to burn more of it.  It is a less intense flame, you could never silver solder with it, but not too severe on a small copper boiler and not too hot means most unlikely to damage the boiler.  Probably not the answer for a passenger carrying 5 inch gauge loco, but more than adequate and very safe for running a small small engine.  Even those small gauge locomotives such as run by Zephryn and Paul, so well loaded for their size.  My engines are 12 mm bore with 12-16 mm stroke double acting and my small burners and boilers run them at up to 2000 rpm by my digital tacho, so more than adequate I feel.

A good source for a commercial burner is the Trangia stoves used by hikers.  (Not the ones sold as warmers for food dishes, which tend to be too gentle.). The whole outfit with cooking pans etc is expensive, but light weight for hikers, but the replacement burners are quite inexpensive at hike equipment shops.  Ideal for your vertical boiler.  Looking at the full kit will give you ideas for making the firebox, with air holes near the base below the flame, and how much height they allow between the top of the burner and the base of the cooking pan.  One fill of 30 -50 ml will raise steam and give 10-15 minutes run time if you insulate the boiler.  Obviously you will need to make something with a separate tank if you want to run for a lot longer and use your feed pump.  Otherwise, when the fuel runs out, top up the boiler with the pump, refil the burner, and you are soon away again.

MJM460
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on October 11, 2018, 06:44:01 AM
Hi MJM.

The more I hear about meths, the more I like it!

Funnily enough I had toyed with the idea of adapting a camping stove. Is it something like this that you mean?

https://www.amazon.co.uk/Trangia-Spirit-Burner-with-Screwcap/dp/B000AR7970/ref=sr_1_1?s=camping-hiking&ie=UTF8&qid=1539235735&sr=1-1&refinements=p_4%3ATrangia (https://www.amazon.co.uk/Trangia-Spirit-Burner-with-Screwcap/dp/B000AR7970/ref=sr_1_1?s=camping-hiking&ie=UTF8&qid=1539235735&sr=1-1&refinements=p_4%3ATrangia)

If so, what would be the advantage (if any) over a home made burner with a cap with say four wicks held in brass collars?

Thanks for your input.

gary
Title: Re: 3 inch boiler build
Post by: MJM460 on October 11, 2018, 08:33:33 AM
Hi Gary, yes, that's the one.  The advantage is that ring of little holes around the opening.  When the unit heats up, the Meths in the bottom starts vapourising, and the burn switches from gentle flame in the middle to little tongues of blue flame from each of those holes.  I suspect a bit hotter than a wick flame.

MJM460
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on October 11, 2018, 12:19:22 PM
OK thanks - will bear it in mind.

Cheers,

gary
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on October 16, 2018, 11:15:37 PM
Well, not such a successful day today.

My tests of various firing methods continue. Today I tried wood - small pieces of bone dry hardwood in fact.

Because the boiler is small and only has five tubes, I reasoned that a large, tall, bell-shaped firebox would funnel the heat up into the boiler and compensate for any lack of draw. I rigged up a rough version of this out of a couple of iron and steel water pipe ends and connectors that I had scavenged from a skip some time ago.

I don't have an electric blower but I did use a small blowpipe to enliven the fire ('inspired by the 'boufadou' as used in France instead of bellows). I now also have a steam blower fitted to the boiler.

The arrangement was not a success. The tall firebox only served to hold the boiler too far above the heat. Lack of ventilation led to a situation in which the fire would blaze with the blowpipe on it but would dwindle as soon as I stopped puffing. The steam blower tugged valiantly at the fire but ultimately there was just not enough heat getting to the boiler.

This is not a major problem as the boiler has already performed heroically on both gas and meths. However, I would also like to be able to run it on wood, coal and charcoal if possible, so I will persist. This evening I began radical surgery on the firebox in an attempt to fix the above problems. The next firing will see the boiler sitting closer to what should be a hotter fire, and I may use charcoal for it.

That could be some time away, as I'm going away next week and when I come back I'll have to temporarily shift focus on to other projects from early November up to Christmas, as there are a couple of special presents I plan to make.

None of this seems to happen quickly...

gary
Title: Re: 3 inch boiler build
Post by: Gas_mantle on October 17, 2018, 12:03:21 AM
Gary,

Could you try with softer 'splintery' wood that may burn easier? I think in relatively small quantities hard wood might be difficult to burn well enough.

Before I bought an electric blower I used my Hoover close to the chimney!  It works well but don't get too close with the hose as it sucks red hot embers into the Hoover body  - I'll leave you to figure out how I know that  :Doh:
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on October 17, 2018, 06:31:56 AM
Peter -

you may be right about the wood. Thanks for the tip. I'll continue to experiment with various forms of solid fuel but I think the firebox modifications are required anyway. The boiler looked good on the tall firebox - kind of Middle Eastern, a bit like some kind of sheesha pipe that you see guys smoking outside Lebanese cafes on Marylebone High Street - but it was just too far above the fire, so the top part of the firebox shell was in the lathe last night, getting sliced down to a less imposing size.

I'm not 'drawn' (no pun intended) to electric blowers, and if I find that I can't do without one for solid fuel, I'll probably just opt for meths.

I had a similar experience with our vacuum cleaner - I hoovered up a red hot ember from our woodburner. We still have the same vac, as my untidy-looking silicone repair on the plastic housing has held good for several years   :Mad:  :)

gary
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on October 25, 2018, 11:57:31 PM
I'm part way through altering the firebox to a design which I *hope* will make it more conducive to running on solid fuel.

However, I'm off to France tomorrow and also have some other projects I need to temporarily turn to and they may occupy me right up to Christmas so there will be little for me to say about the boiler in the interim. I'll pick it up again when I have dealt with the other things, and post some photos at that point.

Meanwhile, and entirely separately from all of the above, I just treated myself to these two little gems - Mamod SE1 and SE3:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/814879.jpg)

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/814880.jpg)

Reasons?

1. Nostalgia - I had an SE1 when I was a kid.

2. It's going to be a while before I finish the boiler and build my first engine, so this will be an easy way for me to witness some engines running in the nearer future.

3. My first engine will be an oscillator, so the Mamods (although way smaller) will give me a first-hand 'feel' of the build and functioning of such engines.

4. They are little objects of desire.

 ;)

They will need some restoration work at some point - as though I don't have enough projects on my plate already!
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on November 08, 2018, 10:47:39 PM
...the heating value of Meths is about 26000kJ/kg, only about half that of other hydrocarbon fuels such as propane and butane, so you have to burn more of it.  It is a less intense flame, you could never silver solder with it, but not too severe on a small copper boiler and not too hot means most unlikely to damage the boiler. 
MJM460

When I was in France the week before last I found some of this in the supermarket - alcool a bruler ('alcohol to burn'):

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/816390.jpg)

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/816389.jpg)

It's 88.4% denatured ethyl alcohol - in other words, I think, methylated spirits.

It's clear and colourless and smells quite sweet rather than the more mineral smell of meths. It's billed as for use as a cleaner, degreaser, solvent and fuel for spirit lamps such as those in fondues. I tried it out on one of the mamods and it did the job but I haven't fired that one on meths yet so can't make a side by side comparison. I'll try it on my boiler at the end of the year when I have the 'pre-Christmas' projects out of the way. I'm guessing it will be pretty much the same as meths bearing in mind the active ingredient is the same.

The main thing is that at 1 euro 92 cents per litre it's a fraction of the cost of meths in the UK, so I bought four litres of it...
Title: Re: 3 inch boiler build
Post by: MJM460 on November 08, 2018, 11:19:23 PM
Hi Gary, that should be worth a try.  I would be interested to know what forms the rest of the composition.  Meths is usually about 95-96% ethanol, with the rest water.  (It is quite difficult to enrich it more than that by simple distillation).

But 88%?  I wonder if the rest is something more flammable than water, some sort of oil to make it smell better for food warming etc.  Worth a try in the Mamod burner to see how much steam it makes.  Also set a small quantity alight in a flat baking dish in a safe place and check that you can extinguish it with a glass of water as you can with Meths.  I suspect you will be able, as the water absorbs the Ethanol, cools and extinguishes it.  Water on an oil fire floats and spreads it which is why you don't normally use water on a liquid fuel fire.

I thought I had commented on those two sentimental items, but don't see my reply.  They are really great but look like they need some TLC.  A great find.  I have a similar little single cylinder one, with the engine mounted on top of the very similar boiler.  It was my brothers when we were much younger.  I like that two cylinder one, it seems to have a basic superheater even.  Should drive Meccano machines well.

MJM460


PS. - Hi Gary, sorry, I see you did try it on the Mamod engine.  If it runs as well as it does on Meths, they are clearly similar enough in heating value, another good find.

MJM460

Title: Re: 3 inch boiler build
Post by: gary.a.ayres on November 09, 2018, 09:02:25 AM
Hi MJM -

I thought you might be interested in this    :)

I have looked around online and most of the info on alcool a bruler seems to be on forums and I find the information to be quite mixed.

However, most people seem to be saying that it contains about 5 - 10 % methanol so presumably along with the 88% ethanol that would bring the water content down to between 2 and 7 %, which it seems would make it similar to meths.

It also appears (from what people say) to burn cleaner than meths does, and so is felt to be better for cooking.

I would tend to trust the French on things cooking-related - they don't take any nonsense when it comes to food !

It certainly ran the Mamod (the single cylindered one above, which is now under pre-Christmas restoration  :)), but I have not yet made a direct comparison with meths. When I do so I probably won't be very scientific about it, but it should be obvious if there's a big difference in performance between the two. I'll make a posting here when I have done so.

My guess is that it will behave pretty much like meths, but more cleanly. If I'm right, it will be the way to go for spirit firing my boiler in the future, especially as it's a quarter of the price (though I do love the purple colour of meths...  8))

Thanks for your input   :ThumbsUp:
Title: Re: 3 inch boiler build
Post by: Steam Haulage on November 09, 2018, 09:34:43 AM
The main component is ethyl alcohol CAS:64-17-5, that's on the label ( Thank goodness for REACH). (Registration, Evaluation, Authorisation of CHemicals)

It also says denatured, that might be by Bitrex or might be by addition of Methanol making it methylated spirits. Don't drink it. The methanol, if used, could itself contain water. It's not required to name the denaturant used.

You will also see from the label that it is not sold as a food additive. More likely it is for camping stoves or lumenaires, or even for mosel boiler burners?

In France it should be cheaper than in the UK where tax might be applied. I do not know the detail of French tax laws.
Title: Re: 3 inch boiler build
Post by: MJM460 on November 09, 2018, 10:07:02 AM
Methanol would make total sense, I think it might even be considered a denaturing agent in its own right as it is definitely poisonous.

It is definitely flammable, it has a slightly lower heating value than ethanol, but also a bit lower boiling temperature.  This would lower the boiling point of the mixture so it would likely burn at a greater rate, which would tend to reduce any noticable difference for our purposes.

I wish we could find it at that price here as we use a Meths cooking stove when we are sailing, so we burn a fair bit of it.  Interesting that your Meths is coloured, ours is clear, but has a smelly poison added.  Not that my wife or I notice any smell in a well ventilated boat.

It will be interesting to see how it goes.

MJM460
Title: Re: 3 inch boiler build
Post by: Zephyrin on November 09, 2018, 11:51:55 AM
de "l'alcool ethylique dťnaturť " is just ethyl alcohol with something added, usually methyl alcohol, to prevent its use as a drink, owing to its awful taste...
and you cannot remove these denaturing compound by distillation as being an azeotropic mix.
don't drink it, it just perfect for steam engine burner...
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on November 09, 2018, 01:43:29 PM
Thanks for your comments, guys. I think that to all intents and purposes this is the French equivalent of methylated spirits, with the methanol added to the ethanol to  dissuade persons of thirst from imbibing it.

Just to be clear: when I said


I would tend to trust the French on things cooking-related - they don't take any nonsense when it comes to food !


I meant that French people would be too discerning to use something like smelly old purple UK style meths in a fondue heater. And yes, MJM - it is and always has been purple here to remind us Brits that it's POISON...!

Have no fear, Gentlemen - I have no plans to either drink the alcool a bruler or to use it as a food additive!   :lolb:

Zephyrin  is well qualified on all counts to point the way here:

 

don't drink it, it just perfect for steam engine burner...

Cheers!

gary
Title: Re: 3 inch boiler build
Post by: zeeprogrammer on November 09, 2018, 01:49:02 PM
Catching up after a long absence...

Congrats on the boiler!

I'll be interested in seeing the restoration of those two gems you got.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on November 09, 2018, 03:26:52 PM
Hi Carl.

Nice to hear from you.

Thanks re the boiler.

I have started on restoring the smaller Mamod already. The larger one appears to be in much better condition but on first try it ran somewhat sluggishly. Further investigation required...

I'll post in this thread when I have made a bit of progress.

Cheers,

gary
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on November 11, 2018, 04:21:10 PM
Still somewhat off-topic, but the picture below shows my third Mamod - an SE2a, with whistle and reversing gear.

So far it appears to be the best runner of the three as well as being in the best condition. I ran it last night (we had a friend staying - after dinner entertainment  :) ) and it went like a demon on the French alcool a bruler. No worries on that score...

Our friend is Russian and he brought a litre of Russian Standard vodka with him. It had a similar effect on me to that which the alcool a bruler had on the engine. Doesn't look that different either...

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/816564.jpg)
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on November 27, 2018, 12:05:58 AM
Still WAY off topic, and trashing enriching my own thread, this is one of the various reasons why there hasn't been much progress on my boiler recently:

VNVgabyVGU8
Will post details of another couple of reasons before I get back to the serious business...   :)
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 09, 2018, 11:28:54 PM
This is what has kept me away from the boiler for the past while:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/818695.jpg)

Two candlesticks as Christmas presents - the one on the left is for my daughter; the right hand one is for my 'other half'. Don't tell them though - it's a surprise...

Materials:

French walnut
Mahogany
Brass
Bronze
Stainless Steel
Aluminium
Copper
and
Reclaimed vintage French plumbing fittings

75 cl bottle of mead for scaling purposes only, you understand.

I got these done sooner than I expected, and am now back working on reconfiguring the firebox for the boiler - will update on that soon...
 
Title: Re: 3 inch boiler build
Post by: Gas_mantle on December 10, 2018, 02:13:57 PM
Very nice Gary, I didn't realise you did wood turning too  :)
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 10, 2018, 02:17:37 PM
Thanks Peter.

I'm very much the novice wood turner (as well as novice home engineer) but I really enjoy woodturning and it's a skill I'd like to develop in the future.

 :ThumbsUp:

Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 11, 2018, 12:15:39 AM
So...

Back on the boiler. Or I should say the firebox as the boiler itself is pretty much finished.

The test firings on gas and methylated spirits went well and raised a good head of steam. However, not so the solid fuel test using small pieces of hardwood in a roughed-out firebox, which failed to produce enough heat. Not to be deterred (not yet, at least), I'm now in the process of modifying the firebox to make it smaller and more compact to keep the heat near the base of the boiler, where it should be. Again, I'll start with a rough trial version in case it doesn't work. No point in wasting time!

However, in such a scenario the top plate of the firebox could be repurposed for use on a meths burner so there's no reason not to make a proper job of that from the outset. That's what I'm doing - or trying to do - now.

First, I cut a small piece off an empty oxygen cylinder from a portable oxy-mapp kit to form a short spigot (it can be seen in rough form in the first picture below). This will be brazed on to the firebox top plate and will fit up inside the bottom collar of the boiler as the conduit of heat from the firebox. A strip of carbon gasket material wrapped around the spigot will form a cushion and seal between it and the boiler.

The top plate is made of 5mm mild steel plate. I used a hole saw to make the initial hole for the spigot then proceeded to bore it to size with a boring head. I plugged the boring head into my new Sieg SX2.7L mill using a 2MT to R8 adaptor, only to realise that the thread on the drawbar of the machine didn't fit the arbour of the boring head. It was Sunday night, and I had neither the wherewithal nor the inclination to make a new drawbar.  Rather optimistically, I gave the setup a go anyway. It worked at first, but as the hole enlarged and the radius of the boring head extended, the lateral forces generated pulled the boring head out of the quill. Not good.

Fortunately, my customized 'drill press milling attachment' (with a drawbar which fits the boring head) saved the day:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/818792.jpg)

This contraption has raised an eyebrow or two in its time, but it has on more than one occasion got me out of a pinch and is actually quite good, especially as the drill press which powers it now has a three phase motor. And there are occasions when a bit of belt slippage is no bad thing...

For details of its workings, see this video:

ldWAuGFDgdA
With the central hole bored to size, I roughly sliced off some of the steel plate with my Evolution Rage mitre saw (wouldn't be without it) to make it manageable, and then back to the Sieg SX2.7L to cut the top plate to just over external diameter using a rotary table and small endmill. I'm finding I really like this mill - for a smallish machine it fairly hogs the metal:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/818791.jpg)

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/818793.jpg)

BTW please disregard the eccentric arc which you can see scribed around the centre hole. This was part of a previous rough marking out and bears no relation to the inner and outer diameters of the plate, which are concentric with each other.

Cheers,

gary


 
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 11, 2018, 10:32:20 PM
The firebox top plate and spigot are now done and are ready to be brazed together and fixed to the main firebox body with M4 screws:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/818841.jpg)
Title: Re: 3 inch boiler build
Post by: crueby on December 11, 2018, 11:30:10 PM
 :popcorn: :popcorn: :popcorn:
Title: Re: 3 inch boiler build
Post by: b.lindsey on December 11, 2018, 11:46:11 PM
Beautiful Gary. I am sure they will love them too. Handmade gifts are the best!! I am referring to the candlesticks though the boiler is coming along well also :)

Bill
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 12, 2018, 10:55:56 PM
Many thanks, gentlemen.

Very kind of you.
Title: Re: 3 inch boiler build
Post by: Ye-Ole Steam Dude on December 12, 2018, 11:19:41 PM
Hello Gary,

I am assuming that you did not turn these on your metal lathe and that you have a wood lathe. If it is a wood lathe what size. Sure would like to see a photo of it. Just beautiful work.

Have a great day,
Thomas
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 12, 2018, 11:51:37 PM
Thomas -

Thank you for your kind feedback. I used all of my main machines to make the candlesticks, including this to make the walnut bodies and mahogany bases:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/818937.jpg)

It's a Coronet Major woodturning lathe and multi-functional 'wood machining centre'. British, from the 1960's. As well as turning it has planer/thicknesser, table saw, belt sander, disc sander and mortising attachments. It's a machine I use for all kinds of stuff, and it's beautiful as well as versatile. One of my favourite machines!

I can't recall the dimensions at present but it's long enough to take a piece of wood twice the length of the body of each of the candlesticks (I had the walnut blanks cut to fit the lathe, and cut one of the blanks into two lengths to make the candlesticks). The wine-sized bottle of mead provides the scale. I'll post some actual measurements here over the next day or two.

As for the walnut, I had a walnut tree right next to my house in France. A local tree surgeon (who is tree-friendly to the point that he has been known to refuse to take down trees needlessly) took one look at it and said 'it has to come down or it will undermine the house'. So - sadly - down it came.

A supply of its beautiful wood is the compensation though!

Thanks again for your interest.

gary
Title: Re: 3 inch boiler build
Post by: Ye-Ole Steam Dude on December 13, 2018, 12:02:34 AM
Thomas -

It's Coronet Major woodturning lathe and multi-functional 'wood machining centre'. British, from the 1960's. As well as turning it has planer/thicknesser, table saw, belt sander, disc sander and mortising attachments. It's a machine I use for all kinds of stuff, and it's beautiful as well as versatile. One of my favourite machines!

Thanks again for your interest.

gary


Hey again Gary,

Wow what an incredible piece of equipment, I have never heard of one that does so many things. Thanks for the info and photo.

Have a great day,
Thomas
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 14, 2018, 12:09:13 AM
Wow what an incredible piece of equipment, I have never heard of one that does so many things.

Yes - the above photo shows the Coronet in my workshop in France. It's now in my small shed workshop here at home, where there's certainly no room for a separate table saw, belt sander, planer, etc.
While it can be a hassle putting on and taking off the various attachments, it does give me a range of options that I wouldn't have room for otherwise.

Cheers Thomas.

gary
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 17, 2018, 06:20:41 PM
Happy Birthday to me!  :wine1:

How could she have known that this was what I wanted...

... if I hadn't told her?

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/819260.jpg)

Will get back on topic soon...
Title: Re: 3 inch boiler build
Post by: Gas_mantle on December 17, 2018, 06:25:19 PM
Happy Birthday Gary  :DrinkPint:

I have exactly the same height gauge and I've been pleased with mine  :)
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 17, 2018, 06:28:25 PM
Cheers, Peter  :cheers:

And good to know. Should help me up my game when it comes to measuring...
Title: Re: 3 inch boiler build
Post by: zeeprogrammer on December 17, 2018, 09:06:24 PM
How could she have known that this was what I wanted...

... if I hadn't told her?

I get my best gifts that way.  ;)
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 17, 2018, 10:39:57 PM
Way to go, Carl.   :ThumbsUp:
Title: Re: 3 inch boiler build
Post by: Kim on December 18, 2018, 05:07:07 AM
Looks like a nice tool there Gary.
And happy birthday!

I think it works best when you give clear hints :)
Kim
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 18, 2018, 09:32:16 AM
Cheers Kim.

I think it's more a case of 'explicit request' though...

 :)
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 18, 2018, 11:10:47 PM
Hi -

In the first photo below you can see the firebox top plate fixed to the top half of the firebox body, which is made of part of the flared end of a ductile iron water pipe. It would have been tricky to hold on the rotary table to perform an indexing operation so I just lined up the top plate, spotted through the holes and drilled and tapped them M4:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/819377.jpg)

Then the fun began. I had to join the spigot for the bottom of the boiler to the firebox top plate, and decided to silver solder it rather than braze it, as I had previously considered. I chose to use high temperature silver solder due to the heat the assembly will be exposed to in use. I took the top plate off the firebox part, and prepped it and the spigot for silver soldering together. A while back I had some problems with my Sievert torch but a quick test yesterday led me to convince myself that The Good Fairy had magicked them away. Not so. The torch went out on me repeatedly, and especially when I tried to turn it up to a decent heat. I went on for ages but the silver solder (which I had cut into small bits and arranged in a ring round the join) simply refused to melt. I scrabbled around the shop for my small oxy-mapp kit only to find that there was no oxygen in the bottle. In despair, and thinking there was nothing to lose, I picked up the part in a pair of tongs, went into the house and lit the woodburning stove in our living room. Placing the assembly in the middle of the kindling wood (and feeling pleased that the small pieces of solder had stuck to the join and stayed put), I opened up the vents of the fire. Imaging my relief as within two minutes the assembly took on a bright orange-red glow and the silver solder flashed round the joint!

:Mad:
:Mad:
:Mad:

OK - the part took a heck of a lot of cleaning up, and the silver soldering isn't the neatest, but hey - this is part of a firebox, not a boiler. It doesn't have to hold any pressure, but even if it did I reckon it would. The black line right of centre isn't as bad as it looks - it's not a gap. And in any case it's going to be covered in black stove paint:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/819378.jpg)

I'm not sure whether to be ashamed of this sequence of events or proud of it.

Too much crazy, but it looks like I got away with it.

I said to my Dear Lady: 'I could build a small tripod out of steel so that I can sit parts on it and silver solder them together in the fire'.

She said 'I think you should fix that torch'.

So the picture below shows where it's currently all at. Just need to fix together the other bits of the firebox, make another few tweaks and I'll be ready for my second attempt with solid fuel. If that fails, it's not a major issue because it would be fairly easy to modify the parts I have fabricated so far to make the housing for a meths burner.

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/819376.jpg)

gary

Title: Re: 3 inch boiler build
Post by: Gas_mantle on December 19, 2018, 12:52:02 PM
Taking shape nicely  :)

With your boiler nearly finished and armed with your new measuring stick have you thought any further about which engine to build?
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 19, 2018, 09:52:57 PM
Still planning on a simple single-acting oscillator to minimise the chances of a failure experience with my first engine.   :)

Aim to make it a one inch bore, though.  Chunky!

Before I start on that, though, once the boiler is done I plan to install the DRO on my new mill.

Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 28, 2018, 09:43:13 PM
So - back on topic.

I got a modified version of the firebox set up on a provisional basis. The apertures for the door and the ashpan are rough, and instead of a door there is a makeshift cover fashioned from a baked beans tin. In lieu of a proper grate there is a grungy bit of thin sheet steel drilled with lots of holes and supported by three coach screws. I saw no point in spending unnecessary time on details before knowing that this boiler (being only 3 inches in diameter with only five tubes) would run on solid fuel. However, the setup was designed to be as functional as possible on that basis:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/819944.jpg)

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/819945.jpg)

Peter (aka gas_mantle) very kindly sent me some Welsh steam coal. Here it is, accompanied by the obligatory sawn-off spoon:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/819946.jpg)

Call me idiosyncratic (or just plain stubborn if you will), but I do not wish to use an electric blower, so I came up with the idea below, which uses a hand-cranked barbecue fan and plumbing fittings. The business end slips into the hole for the ashpan, below the grate:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/819948.jpg)

I was pretty pleased with myself until I discovered that it was virtually useless. I later found that a draught up the chimney is way more effective at pulling the fire than a contraption like this is at pushing it. My apologies to Signor Venturi for thinking I knew better...

Due to the combined narrow diameter of the blower, the small number of firetubes and the dysfunctional blower arrangement I struggled for a good two hours to raise a decent fire. The white spirit blazed, but the charcoal kindling and the coal just sat there. Finally, I resorted to some small pieces of softwood which - to my surprise - burned up nicely with a bit of huffing and puffing and carbon monoxide inhalation on my part. When I got to the point at which I could hear some activity within the boiler, I turned on the steam blower and was astonished by its effectiveness. It was dark by this time. The system became a tiny furnace, roaring away on the barbecue table, sending a jet of steamy smoke and sparks blasting from the chimney:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/819949.jpg)

This was the high point of my day. It was also an opportunity to add more coal and move on to the next level...
... an opportunity which in my inexperience I missed. The fire dropped quickly, and I spent another hour or so trying in vain to recapture that moment.

So, before I give up on coal and hit the meths I will drill a second hole in the chimney and run a small pipe into it from the hand-cranked fan via a reducer. At this point I see no reason why that shouldn't provide a nice Venturi to get the fire up to steam blower level. Or am I always going to struggle to raise steam using solid fuel with this boiler...?

We shall see...

All ideas welcome, of course   ;)
Title: Re: 3 inch boiler build
Post by: Gas_mantle on December 28, 2018, 10:03:10 PM
Gary, I'd be tempted to try your hand operated blower temporarily connected to the steam blower pipe (ie bypass the steam blower) that ought to give you at least some idea whether it will create sufficient updraught, if so it ought to be a simple job to route it up the chimney properly.

I know you don't want to try an electric blower but I do think it worth rigging up some sort of electric fan on top of the chimney - even modifying one of those cheap hand held battery operated fans they sell at the seaside may be better than nothing and they only cost about a quid.

As for the firebox can you temporarily make it less tall? my guess is if the fire was closer to the boiler tubes it may help  :headscratch:
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 28, 2018, 10:41:06 PM
All good ideas Peter. Probably better to try routing the hand cranked blower up the steam blower pipe as a test than to start making more holes in the structure.

I have already reduced the height of the firebox significantly, but your point about a further reduction makes sense to me - will give it some thought.

Fan? Well, maybe - if I have to, having come this far...  ;)

It would be easy for me to just switch to meths at this point, but there was something so compelling about the way it burned and steamed when the steam blower was at full whack. Dynamic and alive. I had never seen that before - but I want to see it again!   :Mad:

Cheers!
Title: Re: 3 inch boiler build
Post by: Gas_mantle on December 28, 2018, 10:46:54 PM
It would be easy for me to just switch to meths at this point, but there was something so compelling about the way it burned and steamed when the steam blower was at full whack. Dynamic and alive. I had never seen that before - but I want to see it again!   :Mad:

Cheers!

Yea coal firing is messy and far less convenient but I think it is a lot more fun  :)

Will it run on wood without the blower once the fire is established? Presumably running the blower extensively uses a lot of water?
Title: Re: 3 inch boiler build
Post by: Zephyrin on December 28, 2018, 11:09:31 PM
Gary, testing you boiler with coal firing first looks brave...
coal firing is temperamental on such small sized grate, too many parameters to control.
I also agree that a electric fan on the top of the chimney to induce draught is a must as the long as the steam blower or the exhaust are not blowing.

And you most probably would need it too with a meths burner in a internal firebox.

You will notice that pressure is still raising with the blower valve just open, with a very low steam output. and steam from the exhaust will also induce a powerful draught, that allows to close the blower
 
the steel sheet with holes which stands for grate will not last more than 5 coal fires at a glance...and a little more with charcoal !
 
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 29, 2018, 12:08:13 AM
Will it run on wood without the blower once the fire is established? Presumably running the blower extensively uses a lot of water?

Peter - without some kind of external encouragement (including the blower) I couldn't keep the fire alive. This was so even with wood, but even more so with charcoal and coal. I'm hoping that if this works it will be straight from hand-cranked blower to steam blower. Today I saw the power of the steam blower for the first time - once it takes hold, no problem I reckon.



I also agree that a electric fan on the top of the chimney to induce draught is a must as the long as the steam blower or the exhaust are not blowing.

And you most probably would need it too with a meths burner in a internal firebox.

Thanks for your input, Zephyrin. I still think it's worth trying my hand-cranked bbq blower routed up the chimney. If it doesn't work I can reconsider.

Interesting to know that about meths burners - I hadn't realised that they could benefit from the assistance of a blower - I thought that was only applicable to solid fuel. However, I'll probably use a different arrangement for meths (or French alcool a bruler!) - am thinking of using a Trangia in a fairly open setup with maybe just a partial windshield but definitely not shut inside a firebox. Having tried the boiler on meths before I'm reasonably confident:

9QwzpgftKict=18s
Title: Re: 3 inch boiler build
Post by: Zephyrin on December 29, 2018, 07:35:16 AM
No problem with alcohol to fire an open fire or a plain pot boiler from underside, I agree, but with an internally fired boiler a vacuum fan in the chimney is mandatory to start steaming !
I also have a lot of excitement when models start to breath...
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 29, 2018, 08:41:48 AM
Zephyrin -

Yes, I got a taste of that excitement yesterday when the steam blower started to draw the fire!

However, regarding alcohol: in the video in my post above it's the same boiler, with five firetubes. It raises steam on alcohol without a fan or any other assistance, as can be seen when the safety valve blows off near the end of the video (9 min 17 sec).

My aim is not to contradict you, but I would welcome your further thoughts as you have considerable knowledge on the subject of alcohol firing.

Salut!

gary
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 29, 2018, 09:45:39 AM
Zephyrin -

sorry - I may have misunderstood you:

No problem with alcohol to fire an open fire or a plain pot boiler from underside, I agree, but with an internally fired boiler a vacuum fan in the chimney is mandatory to start steaming !

You say an open fire *or* a plain pot boiler. So I guess that would mean an open fire would be ok with my 5-tube boiler (as in my video)?

I also assumed by 'internally fired' you meant one with tubes, but perhaps you meant a closed-in firebox...?

In any case, my thinking at this point on alcohol is to persevere with a fairly open burner and assess it as I go along. Some kind of fan assist could always be added afterwards if necessary.

Cheers.

gary
Title: Re: 3 inch boiler build
Post by: MJM460 on December 29, 2018, 11:24:02 AM
Hi Gary,

The issue basically hinges on the necessity for all the combustion gases from your fire to flow through the five small diameter tubes.  If you calculate and add up the cross sectional area based on inside diameter, or flow area, I suspect it will be less than the cross sectional area of the chimney, so more of a restriction to flue gas flow.  On the other hand, if you calculate the surface area of those tubes for heat transfer, which is also the area that provides friction resistance to flow, it will probably be more than the surface area of the inside of the chimney.  Even more flow restriction.  Without gas flow out the top, there is no air flow in at the bottom, so no combustion.

If the combustion chamber is not sealed, combustion gases can escape, so you might get slightly more fire, but unless the gas flows through the tubes, it will not help.

The pressure outside the firebox is the same as the pressure at the top of the chimney, so you have a column of air from the grate to the top of the chimney at combustion gas temperature and cooling as it rises, so the density of air at that average temperature, compared with an equal height column of air outside the boiler at the density for ambient temperature, as all the pressure that is available to overcome the friction of the tube walls and cause the flue gases to flow through the tubes.  It is not hard to imagine that some assistance might be needed.

If you donít like an electric fan assist, and have a handy length of pipe say 2 m long, you could try turning a plug to make a reasonable seal at the top of the stack to increase the effective stack height and hence increase the draft.  I have seen pictures of this arrangement used on locomotive steaming bays.  No idea how much extra draft you need but it is easy to try if you have a length of pipe lying around.  Just remember to insulate it in the section you will hold to support it, or lift it off, as it will get quite hot.

Once your engine is piped up with the exhaust aimed up the chimney to induce some draft you will probably be fine, though some locomotive builders spend a lot of time refining the detail of the exhaust exit nozzle to optimise the effect.    Before the engine starts, a steam or air blower is normally needed for a coal fire and probably for meths.

The horizontal pot boiler does not pose too much restriction to the gas flow which goes around the outside the boiler with much more flow area available than your tubes.  The furnace casing confines the gas to somewhere near the shell for heat transfer, but does not cause much flow restriction.

Two of my boilers are shown in the attached pictures. (Oops, files too big.  Will try agin otherwise they are in the showcase).  Both minor variations on the pot boiler, and one with a stack about 150mm high, the other with a less sophisticated firebox.  The burners are sitting beside the boilers.  My third boiler is a horizontal centre flue type with cross tubes and works quite ok without a blower, but it is gas fired.  The gas fuel is supplied under pressure as a jet along the centre of an air mixing tube.  This gas jet supplies the momentum to overcome the friction through the centre flue tube.  That is a critical difference.  I doubt that the draft would be enough to draw a meths or coal fire through the tube, though Paul and Zephyrin  both run little locomotives which run on meths.  I will leave Zephyrin to tell us if he uses any draft assist.

I hope that helps you understand what is going on

MJM460
Title: Re: 3 inch boiler build
Post by: MJM460 on December 29, 2018, 11:28:17 AM
Got one to post, now I will see if I have one of appropriate size for the other.

MJM460
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 29, 2018, 12:50:50 PM
Hi MJM.

Thank you for your detailed explanation of boiler and flue dynamics.

I think the combined cross-sectional area of the tubes may actually be wider than that of the flue because the middle tube is wider than the other four and is not much narrower than the chimney, which it sits directly underneath. I suspect you are right about the heat transfer area though. Also, there could be quite a bit of friction drag between the tops of the smaller peripheral tubes and the cap before the gases find their way to the stack, as there isn't a great deal of room in there.

However, my boiler is what it is, and short of a major overhaul (which I really want to avoid) it's probably a matter of finding my way round things. I like your flue extension idea, and will use it if my next experiment fails. This afternoon I'm going to jury-rig some tubing which will enable me to direct the air from my hand-cranked fan up the chimney via reducers ending in narrow-bore pipe. I have decided to go ahead and drill a hole in the chimney for this, as the hole can be used for the engine exhaust in due course if my idea doesn't work. I was encouraged by the performance of the steam blower yesterday, and am hoping that my fan arrangement will get the system up to the temperature/pressure at which the steam blower will take over. I'll start with small pieces of softwood (which worked well yesterday), gradually introducing small pieces of coal when the fire really starts to glow. Irrespective of my results with this, I'll probably try your chimney extension suggestion anyway, as overall it could be a simpler solution.

As for meths, well again I refer to my video above (which you have seen before). The thing steamed plenty on a crude jury-rigged burner with no blower of any description to help it. To me that seems promising, I have to say. I have since followed your earlier advice and bought a Trangia but haven't tried it yet.

However, I aim to take the coal trials as far as I can. Once I feel I have done so (whether it succeeds or fails) I'll come back to meths, as I'd like to use both interchangeably if possible. One thing that I have learned from both yourself and Zephyrin is that blowers and exhaust routed up the chimney are helpful with meths. Up to this point, I thought they were only useful with solid fuel.

It's a learning curve, and I have several excellent teachers on this forum!

Love the pictures, by the way. Your engines have an elemental, 'real' quality to them - an aesthetic which very much appeals to me.

Cheers,

gary
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 29, 2018, 06:01:21 PM
I aim to take the coal trials as far as I can.

Well, I feel I did that this afternoon. Again, several hours of frustration, trying to coax the fire to grow and raise steam. I couldn't even repeat my limited success of yesterday. I tried my hand-cranked fan setup - it didn't work. I extended the chimney with a long tube - little improvement. I think this boiler is just too small and lacking enough tubes, as Peter (Gas_mantle) thought might be the case from the outset. Peter - I must add - has been hugely supportive of my efforts with this and has encouraged me to give my plan for solid fuel firing the boiler my best shot, while at the same time being realistic about the possibility that it might not work.

Might it work with an electric blower? Well, I have resisted that option, but given the lack of alternatives I'll think about it over time.

Another option would be to keep the firebox and see if it works with a four inch boiler in the future - all I'd need to do is widen the hole at the top.

But now it's time to draw a line and go on to meths. Back out to the workshop this evening to clean the boiler up and make a start on some trial setups with the Trangia I bought.
Title: Re: 3 inch boiler build
Post by: simplyloco on December 29, 2018, 06:13:43 PM
SNIP
But now it's time to draw a line and go on to meths. .

I know the feeling well, but these days I prefer my own gin... :cheers:
John
Title: Re: 3 inch boiler build
Post by: Jo on December 29, 2018, 06:19:51 PM
I know the feeling well, but these days I prefer my own gin... :cheers:
John

Its always nice to know there are uses for those off cuts when we make a boiler   ;)

Jo
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 29, 2018, 06:50:35 PM
I prefer the French alcool a bruler myself. Doesn't make your tongue go purple like meths does.

 :wine1:
Title: Re: 3 inch boiler build
Post by: Gas_mantle on December 29, 2018, 06:53:02 PM
Sorry to hear it isnt going to plan Gary  :disappointed:

I think you did a fine job of building it so even if coal firing isn't an option it's still a project to be proud of.

It's similar in construction to my 3" boiler and I have pretty much the same problems that your are experiencing, having said that though you have put considerable effort into building it so I'd be inclined to try again after a few more improvements.

Firstly I think an electric blower will be an improvement on your hand fan and although you are reluctant to try I really think it is worth considering.

Looking at your fire box photo (2nd image in post 210), it looks to me that the fire hole opening/door is too low and too big - my guess it the airflow being drawn in is passing infront of and above the coal. Can you fit a tight band around the bottom of the opening and make a closer fitting door so that air is drawn though the grate?

I'd possibly look at making a temporary firebox of a smaller diameter and one where the coal is closer to the fire tubes. It seems to me to be expecting a lot for all that air passing through a large diameter firebox to then funnel into a 1" diameter chimney. My guess is the airspeed up the chimney will need to be fast and consistent in order to have any appreciable draught through the large diameter fire grate.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 29, 2018, 11:23:53 PM
Thanks for this Peter.

Everything you say here makes sense. I have been a bit dogmatic in not being drawn (no pun intended) to electric blowers, but having tried everything else I could think of and failed, it would be sensible for me to review my position!

I take your various points about the firebox design. This may point to a complete rebuild of the firebox, because - as it happens - this evening I have roughed out a housing for the Trangia meths burner, for which I 'borrowed' parts of the firebox. The meths setup is looking good, and I'm inclined to pursue it now because I feel I'm due a bit of progress. This would leave me with two options for solid fuel: (a) to make a new firebox for this boiler along the lines you suggest, so it can run on either fuel by swapping the firebox and the meths burner, or (b) to just keep this boiler for meths, and build or buy a bigger one with more tubes for coal at some point in the future.

At this point I'm more inclined to the latter...
Title: Re: 3 inch boiler build
Post by: AOG on December 30, 2018, 12:34:33 AM
How long was the extender on you chimney? I recall reading that as a rule of thumb for good natural draft, the area of your chimney should be 4-5 times the total area of your fire tubes otherwise your not getting enough delta P for it to be effective.

Tony
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 30, 2018, 12:40:05 AM
Hi Tony -

In reply # 219 MJM suggests a 2 metre length of pipe. I happened to have a piece about that length lying around. It made a good sliding fit inside the chimney so I just used it as is. Smoke came out of the top pretty quickly but I didn't see any significant change in the fire.

Due to my firebox design, I think. Time to re-evaluate...

gary
Title: Re: 3 inch boiler build
Post by: Gas_mantle on December 30, 2018, 12:48:29 AM
Gary, I can see the sense in increasing the chimney height but if you you do it by sliding a tube into the chimney you are further constricting the airflow.

I'd be inclined to further experiment with the firebox and blower arrangement unless you can lengthen the chimney without reducing its cross section area.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 30, 2018, 12:53:39 AM
No problem with alcohol to fire an open fire or a plain pot boiler from underside, I agree, but with an internally fired boiler a vacuum fan in the chimney is mandatory to start steaming !
I also have a lot of excitement when models start to breath...

I did a brief test on 'alcool a bruler' this evening in a Trangia burner mounted on a small column inside a fairly open, airy housing. When I sat a sheet of brass on top of the housing, just as an experiment, the flames died down due to lack of air and no updraught. When I took the brass off and sat the boiler on the housing, the flames rose and gathered into a neat and hot cone pointing up the firetubes. This is looking good...

I'm going to go with this for a while now and try to get it ready for actual use so I can start looking at building my first engine. Details and pictures in due course.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 30, 2018, 12:58:41 AM
Gary, I can see the sense in increasing the chimney height but if you you do it by sliding a tube into the chimney you are further constricting the airflow.

I'd be inclined to further experiment with the firebox and blower arrangement unless you can lengthen the chimney without reducing its cross section area.

Fair point, Peter. Thinking about it, I'm guessing that's what MJM actually meant.

Will keep all of this in mind for when I come back to solid fuel (maybe with a bigger boiler), but I have done a lot of inconclusive experimenting and now feel it's Decision Time, hence going with meths as the next step.

Probably...
Title: Re: 3 inch boiler build
Post by: MJM460 on December 30, 2018, 09:06:38 AM
Hi Gary,

I have not disappeared, but with 10 hours time zone difference and holiday schedule (or lack of it) here, the conversation has certainly progressed since yesterday.

I think others are on the right track suggesting that the extended chimney should be larger diameter, rather than smaller than the boiler stack.  I was also thinking of perhaps a turned wooden or cork plug to get a reasonable seal.  Any cold air which enters at the connection will tend to destroy the draft, and that is about the lowest pressure area, so it is important to avoid unnecessary leakage.

I also like Peterís comments about the fire.  If you think about it, if you want to extinguish a camp fire, or the fire in an open fireplace before you go to bed, it helps to spread out the coals. The larger area means the coals lose more heat, and soon are losing more than they produce, so the fire goes out.   On the other hand to encourage a reluctant fire, the newspaper over the fireplace opening trick, or blowing into the base of the fire encourages the air at higher velocity into the kindling, instead of bypassing it, and carefully stoking extra wood so the heat is held in (but allows air flow) means it loses less heat than it produces, so it all gets hotter and soon starts. 

I am sure there is quite an art to coal firing, though I will leave it to those who have had more practice to comment.  But certainly spreading the fire over too large a grate, along with restricted flow through the gas tubes, almost certainly contributes to your difficulties.  The trangia burner, by confining the fuel and combustion to the intended location around the lip ensures the burner operates well, even out in the open.  I am glad it appears to be working well for you.

I am not suggesting a boiler rebuild, though experimenting with a smaller firebox and grate may produce results.  And keep experimenting with all those means of assisting the draft.  Remember that an induced draft fan has to take the heat of the flue gas so no plastics!  A forced draft requires sealing the fire box well and introducing the air under the grate.  You donít want heated air to escape below the boiler, and you want it all to participate in combustion.  Some locomotive operators talk about secondary air, above the grate.  Industrial gas burners also have both primary and secondary air supply and controls.  This all has to be carefully controlled to complete the combustion, but not cool the gas too much, and not destroy the draft - more variables to get to understand.  It all makes interpreting the results difficult, but that is why it is such a fascinating challenge.

There certainly has been a wealth of learning in all you have done so far.  You and all the rest of us will know so much more about what to look for in the next design you build.  I am sure there will be another.  But after you build your engine.  And first, get this one going for steam for your engine.

MJM460


Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 30, 2018, 12:41:07 PM
Hi again MJM -

Yes, these global conversations develop their own rhythms over time...

Thanks for this great post - you have a great deal of knowledge and you communicate it clearly. Much appreciated.

All of the points you have made make perfect sense, and will be invaluable when I come back to solid fuel in due course. Regarding the extension tube, you were very clear about the need to seal it and so on. It was really an impulse on my part to grab the 2 metre length of copper pipe that I happened to have lying around and use it in the provisional way I did. I should have been clearer about that really. Again, I will certainly keep it in mind as an option for the future (but properly set up!).

Part of me remains reluctant to get involved with 'artificial' means of inducing a draft, such as a blower - which is one of reasons I like meths as a fuel. The idea of just letting it gently do its own thing without needing much attention feels nice and organic to me. That's where I'm heading now. It also has its own kind of beauty. And it reminds me of the Mamods of my childhood...

However, the idea of using coal remains a Holy Grail to me at this point, and I do expect to return to it in the future. Whether I do so with this boiler or save it for a bigger one remains to be seen, but I would like a bigger boiler at some point so it may make more sense to look to that for coal firing.

Yes, this thread has certainly been (and no doubt will continue to be) an education to me! So much knowledge and experience shared by you guys... If it has proven useful to others too, then even better.

I will take another look at what you have been doing in your own threads later - not only to return the courtesy but also because I like your approach and aesthetic. However, I'm going out to the shop now to grab an hour on developing the housing for the Trangia before I go to pick up my daughter...

Cheers   :ThumbsUp:

gary

Title: Re: 3 inch boiler build
Post by: MJM460 on December 31, 2018, 06:55:14 AM
Hi Gary, thank you for the nice compliment, it always gives a lift to the soul to find that my contribution is appreciated.  The things that were the bread and butter of my career are proving most useful to understanding so much of our hobby.  After all, it is the same laws of physics.  So it is a pleasure to share, a small contribution in return for all the stuff about engines and machining which I am learning from others.  In machining, I really am a beginner, but I do also have a very good instructor who shows me more of the ďhowĒ whenever we get together.

I expected you to try what ever pipe you had to hand, (though not plastic) and there is learning whether it works or not.  A lot quicker than trying to calculate the answer.  I would expect a larger diameter might be more helpful, but again, difficult to predict by theory how much better.  With only a small pipe to hand, I also would have tried it.  The same volume of gas through a smaller diameter requires more velocity.  The friction losses tend to be proportional to velocity squared, so increase quickly with a smaller diameter chimney.  Likewise with a larger diameter, they rapidly reduce, leaving the draft to draw the air through the firebed and flue tubes with minimal extra friction to overcome.

All my reading on model locomotives suggests that some form of draft assistance is normally required.  Many of industrial furnaces have had induced draft or forced draft fans in addition to a tall stack.  I agree with your preference for natural means, so probably exhaust steam when the engine is running, but how to get enough steam to start?  Perhaps a small auxiliary boiler, meths fired, like one of your Mamod boilers.  This would not be far from full scale practice.  Ocean going ships often have somewhere on board a small generator driven by an engine that can be hand cranked to start, to generate enough power to get the main equipment started in case some fault trips everything.  It was called a ďBlack Start GeneratorĒ.  At sea in the dark, the engineer needs some way to get started without outside assistance once the problem has been fixed.  Some land based remote mining or oil facilities have something similar, though there are more options for land based plants. 

By the way, you can see the similarity to the little Mamod boiler in my first boiler, in fact, itís first firing actually used the Mamod burner.

But with the long term plan in mind, what ever gets you started provides information on how much draft you need, and even whether draft alone is sufficient to achieve the performance you require.  You can always replace your initial attempt when you know you have the right problem.

I hope the Trangia adaptation works well, looking forward to the continuing story.

MJM460
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on December 31, 2018, 01:33:56 PM
Hi MJM460 -

Using a small boiler to drive a steam blower is an excellent idea! The fact that the other day the boiler was going like a demon on wood for a little while when the steam blower was active suggests that with some additional draughting on startup the system might be viable. And making a small meths-fired pot boiler would be easy enough and a nice project in its own right.

I'm going to go ahead and get the housing for the Trangia made, as I'm pretty sure that I know where I'm going with that and feel it's time (hopefully!) for a success. But after that... well, I was looking at some lovely bits of pipe of various kinds that I liberated from a skip outside our local water provider's works and one of them would be ideal to make a smaller, neater and simpler firebox, as suggested by Peter and yourself... so I might still yet give it a go   :)  Also, fitting a door to the previous firebox was going to be tricky, whereas with the idea I have in mind it would be relatively easy. I have been kindly offered a loan of a fan blower so I may accept that to see if the new system works, and if it does I'll seriously consider your starter boiler idea.

But I'm getting ahead of myself here! I'm in the midst of doing the meths burner so I'll stick with that for now. Some photos later...

Happy New Year to you, Peter and everyone else on this great forum.

 :cheers:

gary
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on January 01, 2019, 01:06:39 AM
Currently working on the housing for the Trangia meths burner.

I cut the flared end off a ductile cast iron water pipe and faced the cut end:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/820243.jpg)

Twenty minutes with an angle grinder and five million years with a file...

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/820242.jpg)

...plus spotting through the holes in the end cap from the old solid fuel firebox using my new transfer punches, and drilling and tapping resulted in this:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/820244.jpg)

Beginning machining a slab of brass for the base (and showing off my Christmas present):

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/820241.jpg)

And that's it until tomorrow.

Not too bad a day's work I reckon.
Title: Re: 3 inch boiler build
Post by: Zephyrin on January 01, 2019, 09:31:03 AM
 steam raising fans are commercially available and pretty expensive, but most of us can do it for nothing, just need a look at the junk box in the home workshop...
As soon as the alcohol burner is enclosed, it requires a draught to burn consistently.
A butane burner is far simpler to use as regard to draught.

http://argyleloco.com.au/product/draft-fan-2/
http://trains.de.jardin.free.fr/minidampf/brazil_uk/steaming.html



Title: Re: 3 inch boiler build
Post by: gary.a.ayres on January 01, 2019, 12:51:04 PM
Thanks Zephyrin. Nice picture and cool little loco  :-)

The alcohol burner housing I'm building is fairly wide open, with a fair bit of room round the burner for air to circulate. On testing a mockup of it the Trangia burned fine with the boiler in situ. I think it will be ok, but I'll see how it goes. If it does struggle, there's plenty of room on the housing for me to drill some big holes.   :) 
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on January 01, 2019, 10:59:38 PM
Continued with the meths burner housing today.

Drilling the fixing holes for the base:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/820360.jpg)

I'm liking my new transfer punches:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/820358.jpg)

The various components - the housing, the burner plinth and the Trangia alcohol burner. The ductile cast iron water pipe end which forms the main body is lined with a tough plastic material. I like the blue colour, which I think goes nicely with the brass base and aluminium plinth, so I decided to keep it. There's a fair chance it will start to melt or scorch from the heat and need some attention, but I'll cross that bridge if and when I come to it. The exterior was painted with black stove paint :

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/820359.jpg)

Almost complete now - I just need to fix the various components together:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/820361.jpg)

Here it is with the boiler in situ. I tested the setup a few evenings ago with a jury-rigged version which was almost identical in principle, so I see no reason why it shouldn't work. However, if the height of the burner needs to be changed, the plinth can be adjusted, and if it needs more air, holes can be drilled in the housing. Hope to have it all fixed together and tested sometime over next weekend:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/820357.jpg)

gary
Title: Re: 3 inch boiler build
Post by: Gas_mantle on January 01, 2019, 11:43:14 PM
Taking shape nicely  :)

Are you intending to add wood cladding once it is up and running ?
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on January 02, 2019, 06:28:39 AM
Thanks Peter.

At this point I have no plans to do so, but I wouldn't rule it out in the future. I'll consider it if and when I get to to the point that I'm trying to squeeze more efficiency out of the system.

I also quite fancy the idea of some kind of insulating fabric covered in polished aluminium sheet, but I suspect it could be a nightmare getting all the holes for the bushings line up properly in the aluminium...
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on January 02, 2019, 06:29:44 AM
BTW thanks to MJM460 for the idea of using the Trangia burner.

 :ThumbsUp:
Title: Re: 3 inch boiler build
Post by: MJM460 on January 02, 2019, 10:04:06 AM
You are welcome Gary, they seem made for vertical boilers, and you can see some similarities in my rectangular ones for horizontal burners.  Still room for experiment I think.  Need to improve my tin smithing skills!

I am looking forward to seeing some success with the trangia.

MJM460
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on January 02, 2019, 12:28:12 PM
Cheers MJM460   :)

I just took another look at your pictures and see what you mean about the similarity to the Trangia.

I also find sheet metal very tricky but I suspect your burners would outperform the Mamod type with just mesh on top...

BTW this is interesting on the subject of alcohol burners:

https://www.youtube.com/user/tetkoba
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on January 02, 2019, 10:17:49 PM
I was unhappy with the number of flutes in the column of the burner plinth I made yesterday, so I made a new one with 12 divisions instead of 8:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/820488.jpg)
Title: Re: 3 inch boiler build
Post by: crueby on January 02, 2019, 10:39:59 PM
Very good looking!!
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on January 02, 2019, 10:44:25 PM
Thank you   :)

That said, while I think the overall look is nice in terms of proportions and so on, there are a couple of aspects of that plinth I'm still not overjoyed with, including the standard of milling of the flutes, which I know I can make a better job of.

I might redo this part yet again, but I'm going to test it for optimum burner height before I do.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on January 05, 2019, 12:28:19 AM
Well... I tested the above arrangement today, only to find that the setup would raise but a meagre amount of steam. Not enough though!

Trying the Trangia at different heights relative to the bottom of the boiler did make a bit of a difference, as did the steam blower, and the beginnings of steam made themselves apparent, but the pressure gauge held resolutely to  zero.

Was it because the Trangia was too shut in and not getting enough oxygen? The next experiment should help to clarify that (Trangia, with boiler supported by an open framework).

Noteworthy though that again today my primitive four wick meths burner did raise decent steam ( as per video above), albeit perhaps against all odds. Maybe a way forward...?

And a forum friend has encouraged me to consider gas as an alternative. Well, no harm in keeping one's options open, I guess...

This is all more tricky than I expected but I'm not out of ideas yet...

Will keep tinkering, and post the results...


Title: Re: 3 inch boiler build
Post by: Gas_mantle on January 05, 2019, 12:59:57 AM
Gary, what does the Trangia burn like in the open air? That ought to give you a bit of an idea if it is an airflow problem.

Does it burn better off the metal plinth? I understand those burners need to get hot to vapourise the meths and 'force' it through the jets. I very much doubt the plinth will be conducting the heat away but it's something that costs nothing to try.

Does the level of the meths make any difference?
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on January 05, 2019, 01:26:20 AM
Peter -

on how it burns in the open air - that's why I plan to test it with the boiler on an 'open framework'.

I suspect the plinth is a red herring. It's aluminium, and doesn't pull away much heat.

Level of meths - seems like a pretty constant heat until it nears empty.

I suspect airflow is the issue, unless the Trangia just doesn't put out enough heat for this particular job..

Will get on to it.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on January 07, 2019, 11:28:08 PM
Following my unsuccessful attempt (details above) to raise steam with the Trangia in a partially enclosed housing, I made a new trial setup which is wide open in structure and tested it this evening. I decided to simply fire it and wait and see if it would get the safety valve to blow off.  This evening, the Trangia slowly but surely raised steam. It took 50 minutes from cold and just over one fill of the burner with alcohol to blow off the valve without using the steam blower. The suppliers of the valve told me it was rated at 45 psi, but the gauge showed closer to 70 by the time it blew. How accurate the gauge is I do not know. I then played around with the steam blower for a bit and enjoyed the definite way in which it pulled at the flame. The Trangia throws out less heat than my crude four-wick burner but it burns in a much cleaner and more controlled way.

This was hardly a controlled experiment as I carried out this evening's test inside my workshop whereas the previous attempt took place outside. I am therefore left wondering whether tonight's firing was much better because of the burner not being shut inside a housing or because being indoors the flame wasn't being blown around (although there wasn't much wind the other day). It will be easy enough to check this tomorrow evening by firing it under the same conditions as this evening but with the burner inside the housing rather than open.

A little bit of a feeling of progress this evening. Picture below:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/821037.jpg)
Title: Re: 3 inch boiler build
Post by: steamboatmodel on January 08, 2019, 05:11:59 PM
Hi Gary,
I haven't used a Trianga as a burner in a boiler, but when using them for camping you normally want them 1 to 1-1/4 " below the pot. I have also made and used pop can burners which require the same space.

Gerald.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on January 08, 2019, 10:39:06 PM
Thanks Gerald. Will check my heights and continue to experiment. I think I was probably within that range though.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on January 08, 2019, 10:55:46 PM
My multifuel adventures continue.

This evening I tested the Trangia inside the cast iron housing which features a few posts above. It was tested under very similar conditions to the open structure I tried last night, i.e. indoors, same burner height, similar amount of water in boiler. Last night with the open structure it took 50 minutes from cold before the safety valve blew off. This evening with the cast iron housing an hour and a quarter in and still nowhere near. There was also an acrid smell - not overpowering but unpleasant. I'm not sure if this came from poorly combusted alcohol or from the plasticky paint inside the housing, but I gave up the ghost and turned off the heat. So, even though I thought that the housing was plenty open enough, clearly it wasn't, so I'll use the open structure if and when I fire the boiler with the Trangia in the future. I guess this could be an option for indoor use.

Zephyrin had it nailed - of course  :)

Meanwhile, look what landed in my back yard today:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/821091.jpg)

Hitherto I have resisted gas, but I took some good advice and decided to cut myself some slack and keep my options open. When I saw how furiously this bad girl burns when you open up the throttle, I realised why it's a popular option. Doesn't look like raising steam will be a problem   :Mad:

Mods have already begun on the gas burner. I know each situation is different, but any advice on the optimum distance between this standard size burner and the bottom end plate of a 3 inch boiler will be welcome...

gary
Title: Re: 3 inch boiler build
Post by: MJM460 on January 09, 2019, 06:10:19 AM
Hi Gary, still following along.  Sorry I have been a bit quiet the last few days.

A few comments to bring me up to date with my thoughts and observations.

The point about heat conduction to the plinth from the trangia burner might be important.  Meths has to warm to 93 deg before it boils to make the vapour that issues in blue tongues from the holes around the rim.  Heat loss through the base might limit the amount of meths that could be evaporated.  A disk of cork or ply, or replacing the Al plinth with a wood block would be worth a try.

I see two issues in the air flow, getting enough air to mix with the fuel and then getting the combustion gases to flow through the boiler flue tubes.  It looks like you have plenty of air flow to the burner, but your boiler flue tubes present a very small flow area compared with the intended use of this burner where the combustion gases flow up the outside of a pot around the full circumference.  This might be why you are needing tome spassisted draft to get enough flow through the tubes.

I expect you might get more heatfrom the gas burner, definitely worth a try, but may still have the same issues getting enough hot gas flow through the tubes.  Again some draft assist might be required.

I donít know if those safety valves arrive preset, but I suspect you have to check them before relying on them.  I tend to be suspicious of very small pressure gauge calibration.  A couple of things you can do to get an idea of accuracy.  First, I assume you did manage to lift the valve using pliers or similar to make sure it was not stuck when it arrived.

First, make a replacement filler plug for the boiler that will accept a thermocouple, called a thermowell.  The hole for the thermocouple is blind so does not leak pressure.  I will try and attach a picture to show you the idea.  Then standard steam tables tell you the pressure corresponding to the temperature.

Depending on the safety valve design, you may be able to use a thin rod to lift the valve and use a digital scale to measure the force at which the valve just starts to lift.  Then measure the diameter of the hole which forms the steam passage, it might correspond to a standard drill size.  The set pressure can then be calculated from the force and area.  Mind you there are a few inaccuracies in this method, not easy to tell just when the valve starts to lift, so a bit of inaccuracy there, and measuring small holes is subject to some error.  It is probably reamed so testing with the shank of some drills will give a reasonable idea if it is a standard size.  Again not sufficiently accurate for a boiler inspector, but should be able to tell the difference between 45 psi and 70 psi.

Best is comparing it with an accurate gauge by a club boiler inspector, first cold on air, then checked hot in a steaming test.

All the best for the continuing experimentation.

MJM460

Title: Re: 3 inch boiler build
Post by: gary.a.ayres on January 09, 2019, 07:01:30 AM
Hi MJM460 -

Thank you for your continued input.

I'll try insulating the bottom of the Trangia as you suggest, though whether it will make enough of a difference remains to be seen. Someone else has suggested that a burner with wicks might be a better option for this application, so more experimentation to follow it seems...  :)

I'm hoping that I won't need assisted draught with the gas (or that if I do it'll just be a little bit of steam blower) but I'll find out when I try it. The gas burner seems pretty powerful. I am a newbie at this though, so may be underestimating the issues...

I'm not too worried about the safety valve question at present. I always test it with pliers before firing the boiler (a habit from my childhood days with a Mamod). My guess is that the main culprit for inaccuracy is the gauge but as you say that's unverifiable without another testing method. The boiler doesn't have a filler plug - it has a hand pump and check valve, so I wouldn't be able to install a thermocouple in the way you suggest. For now, I'm content to know that the safety valve works, which it does.

Cheers,

gary
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on January 13, 2019, 11:46:03 PM
I tried the boiler on my gas burner for the first time. I removed the pot stand from the stove burner and set the latter up temporarily on some bits of round stock. Way more powerful than the meths was, as expected - it blew off the safety valve in 15 minutes and I'm pretty sure it would have been much quicker than that if I had turned the flame up higher. It maintained a steady jet of steam from the steam out valve, and I noticed that when I opened the steam blower just to try it, it pulled the flame up into the tubes quite dramatically. However, I think I gave it too much blower as the whole thing went a bit out of control and started to splutter water, at which point I turned off the gas and let it cool down. Overall, though, looking good, and the colour of those flames is to die for:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/821621.jpg)

Meanwhile, in preparation for my next try with coal, I bought this after a fellow forum member kindly drew my attention to it:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/821618.jpg)

It's a quality little piece of British engineering from the 1970's - a cooling fan for some piece of equipment on a plane, possibly military. It appears they are quite often used as blowers. It has the kind of motor which doesn't reverse direction when the polarity of the wires is changed round, so the suction tube has to cover the fan rather than connect to the nozzle. Fortunately I had a copper plumbing reducer which wedges pretty snugly between the three housing screws. Here it is jury-rigged; I think a bit of metallic tape and/or heatproof sealant will suffice to see it working:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/821619.jpg)

Having been given feedback that my last firebox for coal was too wide and not sealed enough, I got started on making a leaner, tighter one:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/821620.jpg)

I am now by no means certain that this boiler - which is 3 inches in diameter with only five tubes - will run on coal (or wood or charcoal). In fact I'd say it's touch and go. But it's worth one more try...
 
Meanwhile - as I want to end up with a few options for firing - I'm waiting for a couple of things to arrive which will further my adventures with liquid fuel...    :)
Title: Re: 3 inch boiler build
Post by: Gas_mantle on January 14, 2019, 12:01:50 PM
That blower looks to be robust piece of kit and ought to improve your chance of coal firing  :)

I wouldn't bother about sealing it to the copper reducer for now, it doesn't need to be a tight seal. Depending on its original purpose you may even need to reduce the speed if it is sucking your coal up the tubes  :Lol:
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on January 14, 2019, 04:36:20 PM
Peter -

I knew you wouldn't recommend anything less!   ;)

Not sealing the reducer is fine by me. One less job to do. It was pure luck that it wedged neatly between the screws.
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on January 14, 2019, 10:56:38 PM
This evening I decided to actually try running the boiler rather than just heat it up and gaze at it in stupified awe while it did its thing.

Using the gas burner, I took it up to 50 psi on the gauge. I had the gas turned up a bit higher than last night and it took me 10 minutes to reach 50.

I then opened the steam takeoff valve a bit, resulting in a steady jet of steam which made a narrow strip of paper which I held in front of it flap. The pressure stayed at 50 until I opened the takeoff a bit more, at which point it dropped a little, but it was easy to get it back up again just by restricting the steam out a bit and/or turning up the gas. I went on like this for 20 minutes, with the pressure between 40 and 50 most of the time. At one point it dropped to 30 psi, but that was mainly due to inattention on my part I think. I pumped in more cold water several times and the system recovered quite quickly from that.

That said, the gas was turned up full for most of it, but this didn't seem to do any harm other than to use more gas...

When I get to lagging the boiler it can only get better...

After 20 minutes, I decided to have a fiddle with the steam blower. I was amazed at the dramatic effect it had even with the gas turned up full. The gauge went up fast, and looking up into the bottom of the boiler I could see the flame being sucked up the tubes. I think the blower on this boiler might be useful even with gas.


I'm tempted to be pleased with this, but the one thing I do not yet know is whether or not that jet of steam will drive an engine.

There's only one way to find out...
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on January 18, 2019, 11:43:39 PM
While waiting for a couple of items to arrive, I made a start on installling the DRO on my mill in preparation for starting on my first engine (which day draws constantly closer). Fixing the display with its bracket to a convenient storage unit made me feel good, and it looks pretty:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/822022.jpg)



Unfortunately, though, it is attached to the mill's axes by nothing at all as yet and so remains decorative for the moment. That said, I did make a start on making the mounting brackets for the glass scales.

 Those of you who have been following this thread will know that the Lixada camping stove gas burner seemed to raise steam with the boiler quite effectively. While I will  continue to use gas as an option, I am nevertheless in pursuit of a couple of funky alternatives. I received two contenders in the post today:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/822023.jpg)

In the green corner we have an eight-wick kerosene stove from China. It has a catalytic converter/secondary combustion chamber/whatever you want to call it. Although it is not a pressurised unit it vapourises the kerosene and generates a fiendish amount of heat. Unfortunately I took no photos. I did shoot some video but that comes later. It cost less than a tenner, including shipping.

In the blue corner we have a pressurised kerosene stove all the way from India. £22.99 including P&P.  It took me a couple of goes to get the hang of it. For those of you who are unfamiliar with these things, it's like an old-school Primus stove - the burner needs to be preheated. In this case I filled the 'spirit trough' (hidden in photo by frame of stove) with methylated spirits and ignited it, thereby pre-heating the vapourising tubes and allowing the kerosene burner to kick in under pressure:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/822025.jpg)

This resulted in a seriously hot flame which rivals the gas burner and which I suspect will raise steam effectively:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/822024.jpg)

Assuming these two bad boys raise steam, they will be hacked and modified as final alternative heat sources for the boiler, which will be fun and allow for some creativity. However, I will wait until I try them on the boiler before chopping them up so that if they don't work they can always be used as stoves or repurposed for something else in the future. Either way, no great loss at the price.

Trials with each of these under the boiler soon.

Meanwhile, talking of stoves, be stunned by this guy's amazing skills:

oMFJFfPOR1Y
gary
Title: Re: 3 inch boiler build
Post by: gary.a.ayres on January 20, 2019, 11:26:17 PM
So, this evening I tested the two kerosene stoves:

First

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/822212.jpg)

then

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/822213.jpg)

The blue Indian pressurising stove emerged as the winner. It's fierce, and almost up there with gas I'd say. It had the gauge up to 50 psi in 12 minutes and the safety valve blowing off in 15. It might do better yet with a bit of burner/boiler distance adjustment. It's also great fun to use and looks fabulous  :Mad:  :)

In contrast, the green 8-wicker didn't even have the needle off the peg in 15 minutes. It's a nice stove of a kind I haven't seen before, and it burns with a very hot flame but a flame of the wrong size and shape. Some fiddling with heights would help, but not enough I reckon. The steam blower made a considerable difference, pulling that soft flame into a neat cone which pushed the pressure up fairly quickly, but this revealed another problem: when the safety valve blew off the flame went out. Not sure why, but it did. That's a problem with this stove because the burner assembly is such that either it or the boiler would have to be removed to relight it. The pressurising one is much easier to relight because the burner is accessible.

It will be very pleasant to use the 8-wick stove to cook a pot of couscous on the patio in France in the Summertime as the barbecue sizzles.

So... thus far the promising contenders are the gas burner and the blue kerosene stove. The square pot stand on the stove will be cut off. I intend to use these two heat sources interchangeably. The idea is to have them both set at the same height so that they can be set in position without doing anything to the boiler. I also aim to make a cool-looking boiler stand and burner supports. However, the proof of the pudding will be in testing the setup out on an engine, so I'd better get on and start building one.

Whether or not the boiler will run on coal assisted by the electric blower remains to be seen, and I intend to have a second go at making a firebox for it. I may do this in parallel with building my first engine, which I shall start once I have the DRO fitted to the mill.

Title: Re: 3 inch boiler build
Post by: gary.a.ayres on January 22, 2019, 12:57:21 PM
The youtube version of the above post:

http://www.youtube.com/watch?v=5E_qofAb01Q

Title: Re: 3 inch boiler build
Post by: gary.a.ayres on February 10, 2019, 10:50:05 PM
There is still quite a bit to do before I can call the boiler finished, but I have decided to pause on it here in order to build an engine so that I can make sure that the boiler will actually run one! That's what it's all about, after all...

I'm just about to start a new thread on the build of the engine, basic and simple as it will be given it's my first effort. When that is done, assuming all goes well with tests, I'll return to the boiler and this thread.

Meanwhile, I have installed the DRO on the y axis of my mill, and am waiting for some parts to arrive so that I can start the x-axis. Here's a video on that - off topic, but no harm I guess:

http://www.youtube.com/watch?v=kYhjgh9H50c