Model Engine Maker
About MEM => Introduce Yourself => Topic started by: gary.a.ayres on June 25, 2018, 11:12:57 PM
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Hi -
I'm Gary.
For the most part I'm a maker with interests in various areas, but earlier this year I had a sudden desire to build some steam engines. I'm a complete novice at this and have not yet started working on them.
However, I do want to run them on steam when I eventually build them, so I have been working on a 3 inch vertical boiler. The photo shows it lying horizontally all set up ready for its first water pressure test - tomorrow!
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/807085.jpg)
When the boiler is done, my plan is to start with a simple oscillating engine and develop from there.
I live in the British Isles but am lucky enough to also have a small house in France where I have a second workshop. I'm currently installing a lineshaft in my workshop in France using a combination of British industrial pulleys and old French wooden ones from cider presses and so on. That and some other things are featured on my Youtube channel:
https://www.youtube.com/channel/UCcqoEWP6pvkHR6f55Vvufiw/videos?view_as=subscriber
Very pleased to be on the Model Engine Maker forum - thanks!
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Hi Gary, welcome to the forum. I'm sure you'll get a lot of good advice here.
I'd love to know how the boiler test goes tomorrow, it certainly looks a nice piece of work :)
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Cheers Peter, and thanks for inviting me :)
You can be sure that you will be the first to know how the boiler test goes!
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Hi and welcome to the forum Gary. Glad to have you aboard!!
Bill
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Hi Gary,
Nice looking boiler!
And welcome to the forum!
Kim
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Thank you both for the warm welcome.
Nice to be here!
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Welcome to the Forum :ThumbsUp: :ThumbsUp:
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Cheers Roger! 8)
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That's a nice start on your boiler Gary :ThumbsUp: Hope the test prove successful.
Welcome to the forum :hi: - should you need it you'll find lots of help here when you start on your engine(s)
Tug
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Thanks Ramon - very kind of you :)
gary
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Hi Gary, welcome to MEM!
Dave
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Many thanks Dave :ThumbsUp:
gary
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Well.... not the outcome that I was hoping for today.
During the initial air test at 15 psi a couple of weeks ago it was apparent that there was a small leak where one of the fire tubes joins the end plate at the top of the boiler. I mechanically expanded the end of the tube which seemed at the time to do the trick as the boiler held 15 psi of air after that.
Today, however, under hydraulic testing to 90 psi that leak has come back to haunt me. I suppose that given this is my first effort I should be a bit pleased that there appear to be no other problems. However, this leak has to go. Further attempts to mechanically swage the tube end (without heat) have only made the leak worse, and it is now dropping from 90 to 45 psi in 30 seconds. I could fiddle about with it more but I'm afraid of stressing the end of the tube. The photos below show the problem - it's the tube at bottom right, marked in blue. You can probably see the stress marks inside the end of the tube but fortunately there doesn't seem to be any leakage on the inside, just round the outside where it joins the end plate.
My thought is to try to deal with it by caulking it with a ring of low temperature silver solder round the outside of the tube. I used medium temperature silver solder initially on that part of the boiler so my hope is that if I can do it this way I might be able to avoid disturbing other joins which seem to be ok at the moment. I'm also thinking of using my small portable oxy-mapp torch (instead of the big bad boy) to keep the heat as local as possible.
Does this seem like a reasonable plan under the circumstances? Or do any of you good people out there know of a better way for me to tackle it?
Photos:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/807131.jpg)
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/807132.jpg)
Thanks,
gary
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Use comsol a low temp soft solder .
Caveat emptor
If you do use it you cannot use silver solder of any type on the boiler.
It’s the stuff they used to caulk a riveted boiler , note it’s the rivets that held it together the comsol stoped it being incontinent
Glad to have you aboard
https://maccmodels.co.uk/silver-solder-and-flux/silver-solder/3mm-comsol-solder-12-coil.html
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Stuart -
thanks for the welcome and the advice.
In anticipation of this event I have looked into the soft solder debate before. TBH I'm a bit wary of it because - as you say - it precludes silver solder afterwards. Not ruling it out, but will be interested to see if there are any other ideas before making a decision...
Cheers,
gary
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Hi Gary
I'm sorry it hasn't panned out as you wanted but from what I can see it looks to be a nice little boiler once you can sort out a few snags. I'm contemplating making something similar as my first boiler build so I'm interested in what other members say.
Maybe its worth starting a new thread in the 'Boiler' section on the forum with a bit more detail of how it's made and what the problem is etc :)
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Hi Gary - Commiserations - been there and know just how you feel :(
As Stuart says, and you are aware, soft solder is really a big no no near silver soldered parts. Personally, given that it is on the outside and easily accessible I would flux the whole end really well and use your lower melting point silver solder to run a fillet around the area.
A silver soldered part takes a higher temperature to remelt so you should be able to do that without affecting the rest but even if you do get it hot enough to re melt that should not be an issue to worry about with plenty of flux on.
Do make sure it's scrupulously clean all over that end beforehand though - looking at the pics it really needs a good pickle before you tackle it
Hope you make a successful recovery
Tug
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@ Peter - thanks. I'm a bit disappointed but not surprised. That leak was too easy to 'fix' when I air tested it :)
My gut feeling is that I can fix it. I'll stick with this thread for now and try what Ramon suggests. If that doesn't do it for me, I'll post in the Boiler section.
@Ramon - that sounds good, thank you. Looks like I'll be needing a new lot of citric acid, as my original bucketful now looks like something out of a horror movie.
If it were you, would you use a small oxy/mapp torch or just blast the whole thing with the Sievert?
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Hi,
stopping a leak in a silver soldered boiler is not difficult, the boiler will not fall apart upon heating...
You need absolute cleaniness, brazing flux and a propane torch for a rapid and localised heating, remove heating as soon as the brasing rod melt in the right place, that's all.
Caulking with soft solder also requires a meticulous cleaning of the parts too, not very accessible by the way, so once cleaned, go for brasing !
and remove the plug to allow air to escape during heating !
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Thank you Zephyrin - that's reassuring.
Cool name, by the way :)
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Hi Gary - good advice there from Zephryn :ThumbsUp:. Yes I would use your Sievert to get a good all over heat at the relevant end. If you can protect the rest of the boiler with some firebrick to isolate the major heat where you want it.
If it's really clean and you place a ring of your low melting point solder around the offending area it should flow just as the heat is right for it and not the surrounding areas, once that occurs back it up with a bit more with a stick of solder .
Can't stress it enough - mega clean, lot's of flux and a good amount of overall heat. Good luck with it :ThumbsUp:
Tug
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I’m really interested in this as I’ve done no silver soldering, but, soft up to 6”in diameter. I would think you could prep the outside of the tube and flux up, and put a bit of solder a the 12-3-6-9 area and apply the heat right down into the tube, concentrating around the inside of the joint :shrug: Just thinking along with y’all
Cletus
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Tug and Cletus - thanks both very much for your thoughts - very kind of you.
TBH I can see how both of your approaches could have their merits, though the small size of the boiler would mean that if I use the Sievert it would inevitably heat all or most of the end of the boiler, which as you suggest Tug might be a good way to go.
The small oxy/mapp torch might be able to point a flame down the tube, though whether that would create enough heat I'm not sure. I guess I could always try that first - it would be a neat solution if it worked. I did use the oxy/mapp to solder on some a couple of pipe nipples last night and the pipe ends were red hot in no time (hotter than I intended). For an intense and very localised heat it's pretty good; for a broader area the Sievert is the weapon of choice.
What I have gleaned so far from Tug, Zephyrin and Cletus is that it's not an insurmountable problem, that cleanliness is paramount (the boiler is back in the pickle already), that a bead of solder round the end of the tube should do the job, and that there may be more than one way of applying the heat to achieve that.
Brilliant so far guys - much appreciated.
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Hello all I would have thought easy flow 2 would be the way to go, but I too have thought of and used comsol before. I’ve been warned off mixing soft and silver solder before - what are the issues?
Sent from my iPhone using Tapatalk
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Hi -
from a somewhat non-technical perspective: I think the lead in the soft solder makes it impossible for hard solder to stick to anything it has touched. Perhaps someone more knowledgeable than me will explain the metallurgy of this...
I'm using silver solder and easi-flow flux, and my aim is to stick with this if I can rather than use soft solder for the repair..
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The propane for the general heat the hole boiler will absorb a lot of the heat the oxy will be more concentrated
used localy to bring the area to final temp on the copper around the tube the tube will heat quickly watch the
temperature as it creeps to were you want it.dont get the tube too hot.The oxy is good to get local area a little hotter when the solder doesn't won't to run in a spot like the spot that missed in the first attempt.
At this stage you can reheat repair with silver solder once you use soft solder you can't go back to the higher temperature required for the silver solder.
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OK, thanks John.
Sounds good - overhall heat with the propane, then oxy/mapp on end of tube prior to applying silver solder.
Makes sense to me - thank you.
gary
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The tube plate flange area will take all the heat the tube is thin and will heat easily your job is to get the plate hot enough before the tube gets too hot while the plate is not hot enough .
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OK John - thanks for clarifying :ThumbsUp:
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Gary your main problem will be that the rest of the boiler is going to attempt to pull the heat away from the joint causing a hot end of the boiler where you are working and a cooler opposite end. As Tug says the use of fire bricks means that once the overall boiler has warmed up the firebricks will keep the general heat in the boiler, that will allow you to bring the local area around the offending flaw up to temperature for the re-silver soldering operation. (Uneven heating can cause these repair jobs to cause other flaws if you have temperature gradients and can kill the flux if it takes too long to get the required temperature :( )
You want to flux around the tube with the flaw but avoid the flux going elsewhere. By having a thin ring of silver solder round the offender in the flux you will see it melt and once it has flowed that is when to take the heat away... then take the fire bricks away to let the whole boiler slowly come down to normal temperature before pickling.
I hope you are going to remove those nasty sharp looking burrs around the insides of the tubes ::)
Jo
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Have to make a comment here Jo - by fluxing the whole area of the end plate (with a nice wet paste of flux) then should the temp reach that that the previous solder melts then that flux is there to cope with the situation. If you get to that situation without flux there you 'could' make things worse in the other areas. It's always better to have flux there rather than to try to get it on as the situation deteriorates .
Worth repeating - cleanliness - flux - heat - in that order ;)
Regards - Tug
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Hi Jo -
very clear advice. Thanks.
I used insulation around the boiler (ceramic fibre blanket) when I was making it and did note how much more efficient it made the process. Will indeed use it or some firebricks for the repair.
As for the burrs, I'd be a liar if I said I had noticed them (too worried about other aspects :ShakeHead:), but now you point them out, there they are as clear as can be! It will be my great pleasure to take a needle file to them once the leak is fixed...
Cheers,
gary
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Ramon -
You and Jo both clearly know your stuff very well.
As a compromise, I'm wondering if I might flux round all the joints separately so that the flux doesn't connect the offending tube end to other joints? That way - I guess - each joint would be protected by flux but the one I'm trying to build up would have more chance of not losing its silver solder to other joints/areas of the cap.
Does that make sense...?
Thanks all for your input on this. Am blown away by how helpful you are...
gary
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Hi -
from a somewhat non-technical perspective: I think the lead in the soft solder makes it impossible for hard solder to stick to anything it has touched. Perhaps someone more knowledgeable than me will explain the metallurgy of this...
I'm using silver solder and easi-flow flux, and my aim is to stick with this if I can rather than use soft solder for the repair..
Yes it’s the lead it poisons the joint area ,in this situation you cannot remove all traces , if the boiler construction is sound ie all calca have been done for stress and yield for the copper it’s a valid repair.
With ref to silver solder this cad free stuf is not as easy to use IMHO. Another tip is if by chance you need to silver solder a bit of aluminium bronze is to mix in a teaspoon of table salt into your flux mix ( note I only use T5 ) others hate it it’s a bit hard to clean up .
As jo has pointed out that tube has quite a lot of damage and thinning , did you use a a three roller expander with a tapered expander rolled in
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Ramon -
As a compromise, I'm wondering if I might flux round all the joints separately so that the flux doesn't connect the offending tube end to other joints? That way - I guess - each joint would be protected by flux but the one I'm trying to build up would have more chance of not losing its silver solder to other joints/areas of the cap.
Does that make sense...?
can't see much point in trying to separately flux each existing joint, once you start heating the flux will flow over most of the tubeplate so may as well flux up the lot from the start.
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@ Stuart - re the thinning of the tube: yes, it worries me a bit that the inside of the end of the tube is a bit stressed due to my (possibly ill-advised) attempts to swage it. I was wondering if it might be an idea to 'tin' the inside of the tube end with silver solder to reinforce it. Would be interested in what you and/or others think about this idea.
The expanders I used have handles like pliers that open out graduated cones. Will post a picture tonight or tomorrow.
@ Jason - Not long after my post on that point that you quote above it occurred to me that the top of the boiler is so small that the flux would just run together, as you say.
Cheers,
gary
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Hi Gary - you've answered your own question just as Jason has commented on.
Not being able to see just how much you have affected the tube by expanding it it's difficult to say but personally, if the leak is on the join where tube meets the end plate I would just simply heat the end of the boiler as previously suggested until the solder flows around the join again. Trying to get sufficient heat inside such a small tube is not going to be easy and could quickly lead to further difficulties, Of course if it is that thin that it is leaking on the inside as well I would be looking at taking the tube right out and replacing it completely if that is possible,
Regards - Tug
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@ Tug -
Yes, I realised after I posted the question that it would be a game and a half trying to keep the different bits of flux separate, and Jason confirmed this.
The end of the offending tube is somewhat stressed but I think it's intact and - I believe - not leaking inside. As before, I thought this through after I posted and came to the conclusion which you have just confirmed, i.e. just go ahead and solder where the outside of the tube meets the cap (in the first instance at least).
Having to take the tube be right out would be a bleak and depressing scenario (and strangely I have been through that in my head today too) but heck I would do it if I had to because I am determined to get this boiler working. It has taken far too much of my energy, time and money for me to even consider giving up on!
Thank you Sir.
@ Stuart -
Two pictures of the pipe expanding tool that I used are below. I used it to slightly flare both ends of the four outer tubes really just to hold them in place for silver soldering (and - to my mind - make a better join). I got this idea from a build log I saw for a 6 inch boiler where the guy used soft solder. I have been advised elsewhere that in my application this was not great practice though I *seem* (touch wood) to have got away with it in seven out of the eight joins. I also used them post-soldering on the problem tube when the leak became apparent during initial air testing at 15 psi. At that point I thought that had fixed it mechanically. If only!
I hope this thread may be useful to other people as it contains a great deal of valuable info from you guys of a kind which was previously quite hard for me to find as I was researching the topic a couple of months ago.
Pictures of tool:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/807211.jpg)
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/807210.jpg)
gary
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Hi All -
Burning the midnight oil here and - having acted on the advice of quite a few of you (Ramon deserving a special mention) there is now a large and not very pretty fillet of silver solder round the end of the offending tube. On repeated hydraulic testing the entire boiler remained bone dry, so your input on silver soldering the repair seems to have paid off.
You guys are amazing! :LittleAngel:
However... I was mystified because the pressure gauge kept dropping despite my having looked and looked and found no leaks or bad connections. I believe I traced it to the clack, as when I lifted the entire assembly up, water was slowly dripping out of the end of the pipe that takes the water from the tank. I tried sealing the end of the tube with my finger while keeping an eye on the gauge (it was late...) but that was inconclusive. In order to be sure that this wasn't just residual water from the pipe draining by gravity, I turned the whole lot upside down and the water was still dripping from the pipe, apparently under pressure. Now, I guess that clacks work by gravity to some degree, but assume that between 50 and 90 psi they should in theory close even if upside down. Am I right in this? If so, I conclude that the clack was leaking a little, causing the drop in pressure. Furthermore, the second clack that you can see in the picture also dripped, so I replaced it with a blanking plug a few days ago.
The picture of my testing setup is reposted below as that might make what I'm saying clearer.
Is it normal for clacks to leak a bit? And if so are they more likely to leak on steam than on water? And can they be fixed?
Meanwhile, as the boiler itself now seems ok, I'm thinking that it's time to move on to its first steam test - unless your responses convince me that I shouldn't!
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/807085.jpg)
Thanks for all your help.
gary
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Excellent news on the boiler leak! :whoohoo:
Having a small leak on the ball valve back at the pump seems to be a common problem, getting the seat for the ball perfect is tough. Did you try seating the ball with a rod and hammer, and also put in a fresh ball afterwards? A seperate shutoff valve can be used too.
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Cheers, crueby.
Such a relief to learn that clack leaks are common (i.e. I wasn't missing something nasty!).
I did not take the steps you mention, rookie that I am, but will certainly do so :)
Many thanks.
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Hi Gary,
I've been through this issue recently with the boiler on my steam tractor. You can read about my dealings and everyone's advice and comments, starting about here in my thread http://www.modelenginemaker.com/index.php/topic,5264.1005.html (http://www.modelenginemaker.com/index.php/topic,5264.1005.html) around post 1015. There's a bunch of good advice there about making a good ball check valve.
I was able to improve mine, but in the end, I used a shutoff valve for my hydro testing to get past the issue.
I figure that losing a pound of pressure every few minutes through the ball valves won't be that noticeable under working conditions. But with the shut-off, I was able to verify the integrity of the boiler, which was the goal.
Best of luck,
Kim
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Hi, as the others said it seems to be quite normal. I made blanking caps for the clacks on mine with an ‘o’ ring in the bottom. The boiler inspector still wanted to see them go up to the pressure to ensure their integrity. Think I may attempt to seat better them with a light tap.
On a boiler your size it won’t take much water to drop the pressure as so it’s probably nowhere near as bad as it seems.
My whistle valve was the worst culprit - it couldn’t be removed from the manifold or blanked off - it’s valve was persuaded with a hammer!!
Oh yes, forgot to add as the others pointed out a shut off valve between pump and boiler is usual on a test rig.
Boiler looks good, looking forward to seeing it in steam.
Sent from my iPhone using Tapatalk
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A CAUTION TO ALL IN TESTING BOILERS
Do not do it outside in full sun at this time of year , if you pump it up to test pressure , great it does not leak , I will go and have a cuppa come back to check the pressure gauge .
You may find the boiler now is over stressed due to the heat of the sun expanding the watta in a sealed vessel
LBSC used to recomend to warm the boiler with a sprite lamp instead of a pump
Take care and have happy steam ups
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Congratulations on a successful recovery Gary :ThumbsUp:
Yep, concur with clacks having a propensity to leak ::) but am always wary of the 'tap with a hammer' approach. That's not to say it doesn't work but a long missed local model engineer of exceptional talent was always adamant that the best way to seal a ball was to drop the ball on the seat then screw in a mandrel to gently force the ball on its location with a twist. A bit of extra work with making the mandrel but worth it.
I have also had good success using an O ring as a seat. Indeed the clacks on the WaW boiler were treated as such. The 'seat' is recessed such to allow an O ring to sit flat and just be held by outer pressure alone. The ball just sits on the O ring. Seal is almost instantaneous once pressure comes on. Had these on my old Twin Victoria plant which ran on steam for years - never had one lift off it's seat. Nitrile ball is another route but these are limited in range O rings providing a far greater choice.
Though I have limited knowledge of operating boilers to today's standards I believe any initial test hydraulic test at 2 x WP should be done with blanks on all outlets. Subsequent test with all fittings is usually at 1.5 x WP - I think.
Another thing to note on a hydraulic test where everything is perfectly sealed is that the pressure will tend to slowly creep back a tad as things settle under pressure - not much though.
BTW one of the best indicators I have found for highlighting any tiny leak's whereabouts is the blue hand roll paper wipe. If the vessel is laid on some of this beforehand any leak is immediately obvious.
Regards - Tug
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Thanks guys. You generously offer a treasure trove of information.
I had read about the tapping method in a book (in K.N. Harris maybe...), but didn't realise that it might apply to valves bought from a supplier as well as home made ones. Also, I had forgotten about it :)
Putting it all together, I will consider the methods suggested for seating the ball, then try one of them. I'll also order a couple of shutoff valves asap - might as well make this as easy as I can on myself :)
I will also look at the thread Kim suggested, and steal some blue paper from the dispenser in our campervan.
Following which I suppose I had better do another final water test with the valve business sorted just to be absolutely sure the boiler is ok (though I'm sure it would have passed the blue paper test last night) before going on to steam.
And most certainly I shall refrain from testing it in the sun.
:ThumbsUp:
gary
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A good point for you and your boiler...
There are many methods to fix valve leaks, the proof that you have to choose your own...while waiting for a general and definitive one !
don't over do the hydraulic test, 2x the working pressure at max, otherwise you may easily see bulging of the end plate above theses figures on such boiler....7-8 bar I would say.
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Tu as raison, Zephyrin.
Listen to other people's ideas, then decide and act...
There will be two clacks on the boiler, so I have ordered a shutoff valve for each line plus some nitrile AND stainless steel balls for the clacks.My plan is to go with the nitrile balls as it sounds earier, but will have the steel ones as spares in case the nitrile doesn't do the job. So, nitrile ball + shutoff valve. Should hopefully do the job!
Re pressure, I have been testing it to 90 psi, which is about 6.2 bar. The working pressure will be 45 psi as determined by the safety valve I have.
Salut!
gary
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Hi -
The saga continues, so I thought I'd better draw a line under my misuse of the 'introduce yourself' thread and start a new one ('3 inch boiler build') in the boilers section:
http://www.modelenginemaker.com/index.php?topic=8280.msg177729#msg177729
Locking this thread now - thanks for your help so far and would be delighted to continue the discussion on the new thread and elsewhere.
gary