Author Topic: boiler stays  (Read 13426 times)

Offline daveclm

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boiler stays
« on: October 23, 2016, 07:32:50 PM »
hi
 im nearly at the stage off silver soldering my boiler, i would be grateful if any could advise me if these stays are ok. i have built 4 other boilers but never done stays before. the stays are made off pb 102 3/16 bronze, the end fixings are 660 bronze. i have looked all over the net but nothing in detail. this is how i was going to do them. i have turned the 3/16 bar down on the ends and threaded them, the bushes are tapped to fit the ends, then i was going to silver solder one end with the bush on with silver flo 24, only on the threads, then install in the boiler silver solder the end that i have solderd with silverflo 55,
then silver solder the other bush at the back end with silverflo 55. hope this as made sense. have enclosed some pict.

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Re: boiler stays
« Reply #1 on: October 23, 2016, 09:21:16 PM »
I'm sure Sandy will pipe in here shortly.

To be of any assistance, we need to know what the materials are.

Has the design been reviewed?

Dave
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Online Jasonb

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Re: boiler stays
« Reply #2 on: October 23, 2016, 09:32:44 PM »
I would have thought it better not to have reduced the diameter of the ends as now the effective cross section is the core dia of the thread rather than the 3/16" dia of the stay.

You could have just soldered solid stays straight in or if you wanted ones with nipples then tap the endplate and thread the OD of teh nipple (bush)

Dave, all the materials are given

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Re: boiler stays
« Reply #3 on: October 23, 2016, 09:42:02 PM »
Ah....Yes.    Not sure about 660 bronze, but Phosphor bronze is acceptable.

What did the plans call for on the stays?

Dave
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Offline daveclm

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Re: boiler stays
« Reply #4 on: October 24, 2016, 10:22:02 AM »
Ah....Yes.    Not sure about 660 bronze, but Phosphor bronze is acceptable.

What did the plans call for on the stays?

Dave
hi steamer
the drawings show that the stays are 3/16", all the bushes are bought from a well known steam fittings place.Bronze - SAE660 Free machining Leaded bar
Not subject to dezincification. Ideal for boiler bushes, bearings etc.
thanks dave.

Offline Jo

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Re: boiler stays
« Reply #5 on: October 24, 2016, 10:51:32 AM »
Bronze - SAE660 Free machining Leaded bar

Leaded bronze  :o I am not sure you want to use that for stays.

Jo
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Offline daveclm

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Re: boiler stays
« Reply #6 on: October 24, 2016, 11:10:09 AM »
Bronze - SAE660 Free machining Leaded bar

Leaded bronze  :o I am not sure you want to use that for stays.

Jo
you have not read the first post that i did correctly,  the stays are 102 ph bronze rod, no lead in. its the bushes that are 660 bronze.

Offline Jo

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Re: boiler stays
« Reply #7 on: October 24, 2016, 11:25:44 AM »
I am pleased to hear that  :)

I have a few bits of both leaded bronze and Ali bronze that are both kept well away from any bronze that I may want to silver solder.

Jo
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Re: boiler stays
« Reply #8 on: October 24, 2016, 11:29:09 AM »
Hi Dave,

If the plans call for the materials, and the dimensions specified, what is the question then?

Dave
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Offline daveclm

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Re: boiler stays
« Reply #9 on: October 24, 2016, 11:39:14 AM »
Hi Dave,

If the plans call for the materials, and the dimensions specified, what is the question then?

Dave
the drawing tells you what materials to use and sizes but not how to do the stays. like i said in my first post.

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Re: boiler stays
« Reply #10 on: October 24, 2016, 11:58:12 AM »
Hi Dave,

Don't worry about quoting, it's all there.    Do you mean how to silver solder them into place?

Your pictures show one of them installed, but nothing silver soldered yet

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

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Re: boiler stays
« Reply #11 on: October 24, 2016, 12:00:03 PM »
I do see that your flue tube has been silver soldered.

Dave
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Online Jasonb

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Re: boiler stays
« Reply #12 on: October 24, 2016, 12:54:49 PM »
As I said earlier if using bushed stays then all the ones I have seen thread the full dia of the stay. The bush is then threaded internally to fit the stay and externally to fit tapped holes in the tubeplate. I suppose you could just solder in te bushes but I would prefer to see then full dia all the way.

I'll scan a picture later of a drawing that shows then done this way.

I have never had a problem silver soldering 660 and it is resistant to dezincification so no problem in a boiler :) though I mostly use it for fabricated cylinders.

J
« Last Edit: October 24, 2016, 12:58:02 PM by Jasonb »

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Re: boiler stays
« Reply #13 on: October 24, 2016, 02:31:49 PM »
As I said earlier if using bushed stays then all the ones I have seen thread the full dia of the stay. The bush is then threaded internally to fit the stay and externally to fit tapped holes in the tubeplate. I suppose you could just solder in te bushes but I would prefer to see then full dia all the way.

I'll scan a picture later of a drawing that shows then done this way.

I have never had a problem silver soldering 660 and it is resistant to dezincification so no problem in a boiler :) though I mostly use it for fabricated cylinders.

J

Jason, understood, but my point is what is drawn on the drawing?, was the drawing signed off for construction?, and does the part conform to the drawing?

I'm being pretty anal about this, because it's a boiler, and I know the laws on that side of the pond are pretty strict.   Now would be a good time for Sandy or a Boiler inspector to inspect the components and make a judgment before it's all silver soldered together.   It's far easier to recover from an error now before that happens.   Now if you're that guy...GREAT!   ....but I am approaching with a great deal of caution.    I have yet to see any stamped drawing that says this is right or wrong.   

Dave
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Damned ijjit!

Online Jasonb

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Re: boiler stays
« Reply #14 on: October 24, 2016, 03:30:40 PM »
Dave, as the OP has said the drawings do not show how to do the stays only that they are 3/16" dia.

"the drawing tells you what materials to use and sizes but not how to do the stays"

My comment was that I did not think reducing their diameter was the best way to do them as all the threaded ones I have seen thread the full dia to give max cross section and therefore strength.

Daveclm, can you let us know what boiler design you are following please.
« Last Edit: October 24, 2016, 03:39:14 PM by Jasonb »

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Re: boiler stays
« Reply #15 on: October 24, 2016, 04:18:01 PM »
Thanks Jason, and I';m glad you understand my point.

Dave
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Online Jasonb

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Re: boiler stays
« Reply #16 on: October 24, 2016, 04:24:26 PM »
DaveCLM is this Julius de Waal's version of the 3.5" horizontal boiler, if so I have the original which tells you how to do the stays.

J

Offline SandCam

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Re: boiler stays
« Reply #17 on: October 24, 2016, 04:44:58 PM »
As I said earlier if using bushed stays then all the ones I have seen thread the full dia of the stay. The bush is then threaded internally to fit the stay and externally to fit tapped holes in the tubeplate. I suppose you could just solder in te bushes but I would prefer to see then full dia all the way.

I'll scan a picture later of a drawing that shows then done this way.

I have never had a problem silver soldering 660 and it is resistant to dezincification so no problem in a boiler :) though I mostly use it for fabricated cylinders.

J

Jason, understood, but my point is what is drawn on the drawing?, was the drawing signed off for construction?, and does the part conform to the drawing?

I'm being pretty anal about this, because it's a boiler, and I know the laws on that side of the pond are pretty strict.   Now would be a good time for Sandy or a Boiler inspector to inspect the components and make a judgment before it's all silver soldered together.   It's far easier to recover from an error now before that happens.   Now if you're that guy...GREAT!   ....but I am approaching with a great deal of caution.    I have yet to see any stamped drawing that says this is right or wrong.   

Dave

Hi Guys,

Daveclm,

The diameter and strength required for stays is determined by the area supported and the load on that area.

Both Jason and Dave are quite correct to question the type and method being proposed.

The 2 facts we don't know are the working pressure and the surface area in square inches that requires the support, hence, to make a sound judgement both would need to be known.

Solid Drawn PB has a typical tensile strength of 31250psi in the fully annealed state, however for stays a x10 safety factor is applied when calculating stay strength under UK boiler stress regulations. (and pretty much the same worldwide)

From the photo's of the proposed stays it would appear that the 3/16"OD  has been reduced to around 1/8th inch dia and then threaded at ,perhaps, 5BA.
This would reduce the effective cross section of the stay to approx 0.0075 sq in. at the root of the thread giving a breaking stress of just 23.4375lb each.

I.E... (0.0075 x 31250) /10 safety factor = 23.4375lb each.

Whereas the full 3/16" stay directly soldered into the end plates would each have a breaking stress of 86.28125lb... which is approx 3.7 times stronger per stay.

Even threading the outside of such a stay and using a dual threaded bush, as Jason has suggested, would still reduce the strength of the stay to that afforded by the core dia of the chosen thread... the bushes do not change this regardless of how big they are.

So, to recap... Davecls can you supply the following: -

Which boiler design are you following.

The working pressure of the boiler.

The outside diameter of the end plates and the thickness of the material used.

The outside diameter of the centre flu.

The horizontal spacing between the stays and the vertical spacing from the top of the end plate.

I can then get a better indication of the expected loading and take it from there.

Meanwhile... don't solder anything yet.

Best regards.

Sandy. ;D


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Re: boiler stays
« Reply #18 on: October 24, 2016, 05:31:54 PM »
Thanks Sandy.

Dave
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Damned ijjit!

Offline daveclm

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Re: boiler stays
« Reply #19 on: October 24, 2016, 06:56:22 PM »
hi sandy
i dont no the name off the boiler, it just says on the drawing horizontal centre flue boiler drawn by af campbell and sandyc argyll scotland.
the boiler tube is 106 copper 1.6mm 16g bought from kennions, dia is 31/2", centre flue is 1 1/2" 106 1.6 16g tube, the end plates are 106 3.2mm 10g i known a bit over board on thickness i allready had it.
the gallow tubes i think thats what they called are 20gauge the stays are 3/16 not 3/8 which i said they where. max wk pressure is 60 psi 4 bar and typical wk pressure 45 psi. the only thing i have changed is the chimmny is on the out side off the boiler. dont know if this makes any difference to the boiler.end plates are just under 86mm tight fit. dont know how tight they shoud be.

thanks dave

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Re: boiler stays
« Reply #20 on: October 24, 2016, 07:10:48 PM »
You're in good hands Dave.....


Dave
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Damned ijjit!

Online Jasonb

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Re: boiler stays
« Reply #21 on: October 24, 2016, 07:23:21 PM »
As said you are in good hands, I'll leave it to SandCam to sort you out who is the SandyC on your drawings though they do tell you how to mushroom the ends of the stays.

It may help Sandy to come up with a rescue plan if you could say what size hole you have drille din the end plates for the bush, hopefully they can still be used but I have a feeling the stays won't be able to.

Offline daveclm

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Re: boiler stays
« Reply #22 on: October 24, 2016, 07:31:13 PM »
jasonb
the holes are sloppy 3/16, same as the bronze rods.

thanks dave

Offline SandCam

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Re: boiler stays
« Reply #23 on: October 24, 2016, 11:20:47 PM »
hi sandy
i dont no the name off the boiler, it just says on the drawing horizontal centre flue boiler drawn by af campbell and sandyc argyll scotland.
the boiler tube is 106 copper 1.6mm 16g bought from kennions, dia is 31/2", centre flue is 1 1/2" 106 1.6 16g tube, the end plates are 106 3.2mm 10g i known a bit over board on thickness i allready had it.
the gallow tubes i think thats what they called are 20gauge the stays are 3/16 not 3/8 which i said they where. max wk pressure is 60 psi 4 bar and typical wk pressure 45 psi. the only thing i have changed is the chimmny is on the out side off the boiler. dont know if this makes any difference to the boiler.end plates are just under 86mm tight fit. dont know how tight they shoud be.

thanks dave

Hi Dave,

So...  af campbell and sandyc argyll scotland... couple of real dodgy character those two... I know them really well >:D :censored: :LittleDevil: :ROFL: :lolb:

Your boiler is known as the MEM 3 1/2" diameter Horizontal boiler and it is in fact one of my designs. :naughty: ;D

If you have all 5 sheets of the drawings then you will find the details for making the stays at the bottom left of sheet 2... just be sure to make them at least 1" longer than required so that installing them is less of a struggle... the excess can be cut off after they are soldered in place (stand the boiler on end with the mushroom heads at the top and solder them first, then turn the boiler over and solder the other end).

You will need to use the full 3/16" dia PB for these stays and silver solder them straight into the end plates after forming the mushroom head on one end and without any threading required, so unfortunately the ones you currently have will not suffice since they are nowhere near strong enough.

Each stay is supporting an area of 1.236 sq ins if spaced as per the drawing and is subject to 74.16lbs of load at 60 psi. and at 45psi the load would be 55.62lbs.

Each stay has a breaking strain of 86.28lb so no fear of them breaking even at the higher pressure.

You mentioned you have used 1.5" diameter tube for the centre flue rather than the 1.75" diameter called for and also that it is 10swg.
This is not a real problem other than you will expend a bit more heat from the burner actually heating the water, since this heat will have to pass through the much thicker walls of the flu... and you will have a bit less heated surface area which will effect the boilers steaming rate.
The other issue will be the burner... you will need to reduce the size of this for both the outside tube ring and the actual burner body in order to maintain sufficient clearance around the inner burner tube for the required secondary air flow.
Reducing the size of the burner will, of course, reduce it's heat output capability and you may struggle to keep steam pressure up... especially if you go above 45psi.

Having the funnel on the outside of the end plate should not be a problem... it certainly makes it easier to build.
The tubes inside the flu are simply called cross water tubes... Galloway tubes are a different thing altogether, albeit they perform a similar task.

You say your stay holes are a sloppy 3/16"... How sloppy?... ideally you need them to be only about 0.002" - 0.003"MAX  larger than the bronze stays since silver solder is not good at filling large voids.(Note... this close clearance applies to all silver soldered joints)

If you don't have the whole set of drawings then just PM me your email address and I will send you a complete new set.

Finally, I see you have chosen not to fit the steam dome... I would suggest you reconsider this since it will help prevent carry over of water droplets into you steam line and also gives you the perfect location for attaching a pressure gauge.

I hope this helps you with the build, however, if there is anything you need more help with then either ask here on the forum or PM me.

Best of luck.

Regards.

Sandy. aka sandyC.  ;D

« Last Edit: October 24, 2016, 11:25:10 PM by SandCam »

Offline K.B.C

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Re: boiler stays
« Reply #24 on: October 24, 2016, 11:42:03 PM »
So...  af campbell and sandyc argyll scotland.. 2- desperate characters indeed, between the two of them there is a wealth of information which they unstintingly give help to those making a boiler .

Dave  when you have the end plates in and ready to solder I would recommend that you drill some small holes around the circumference of the shell, 4- will be enough and insert some copper rivets to hold the plates in place, they don't require to be riveted, leave a very small countersink on the outside of the hole , flux the copper rivets and solder the lot in place, when finished and cool file of the ends sticking out.
There is nothing worse than if when soldering in the end plates and they slip even if they are a tight fit.
I use 3/32" copper rivets to hold in the end plates.

I hope this helps.

George.
Your never too old to learn.

Offline daveclm

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Re: boiler stays
« Reply #25 on: October 25, 2016, 10:28:57 AM »
hi sandy
i thought they where you designs.  i think the holes are to sloppy to just solder the stays in. would i be ok to put 1/4 stays in, turn the ends down to fit the holes i have drilled, or drill the holes to fit the 1/4 stays. will change it to fit the dome. sorry to be a pain in the backside.
thanks dave.


Offline SandCam

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Re: boiler stays
« Reply #26 on: October 25, 2016, 10:37:25 AM »
hi sandy
i thought they where you designs.  i think the holes are to sloppy to just solder the stays in. would i be ok to put 1/4 stays in, turn the ends down to fit the holes i have drilled, or drill the holes to fit the 1/4 stays. will change it to fit the dome. sorry to be a pain in the backside.
thanks dave.

Hi Dave,
Yes if the holes are oversize for the 3/16" stays then just fit 1/4" ones, no need to turn down the ends... just use the same method for forming the mushroom heads and solder them in.

Keep Happy.

Sandy. ;D

Offline daveclm

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Re: boiler stays
« Reply #27 on: October 25, 2016, 11:20:09 AM »
thanks all for the help.

Offline daveclm

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Re: boiler stays
« Reply #28 on: October 29, 2016, 10:57:49 AM »
hi sandy
after what you said about the centre flue should be 1.75 dia and should be 10swg, i was thinking to remake the centre flu, but on the drawing it says to use 1.75 16swg. if it should be 10 swg i will remake it. got the stays sorted and the steam dome, all solder in.

thanks dave.

Offline SandCam

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Re: boiler stays
« Reply #29 on: October 29, 2016, 01:53:02 PM »
Hi Dave,

Oops... It would appear I have slightly misread one of your previous posts... my apologies, however...

Quote
the boiler tube is 106 copper 1.6mm 16g bought from kennions, dia is 31/2", centre flue is 1 1/2" 106 1.6 16g tube, the end plates are 106 3.2mm 10g i known a bit over board on thickness i allready had it

You did state that the current flu was 1.5" dia x 16swg and that the end plates were 10swg... I read it as the flu being 1.5" dia x 10swg, since that was what you had available.

The reason I mentioned this in my post was mainly that the plan calls for 1.75" dia for the flu not 1.5" dia ... The 10swg was my error.

It would now appear to be that the flu is actually as per the plans so please disregard my previous comments about this and the implications it would have made for the burner etc.

The use of 10swg for the end plates will do no harm whatsoever other than make the boiler a bit heavier.

It is good to see that you have upgraded to the steam dome... it will certainly help limit the carry over of water droplets in the outgoing steam.

So your flu is fine so just go ahead and use it.

Once again my apologies for my misreading of things... must go back to specsavers and complain. :Argue: :Jester:

Keep happy.

Sandy. ;D
« Last Edit: October 29, 2016, 01:56:29 PM by SandCam »

Offline daveclm

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Re: boiler stays
« Reply #30 on: October 29, 2016, 02:30:22 PM »
thanks sandy nice 1. can crack on now.

Offline daveclm

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Re: boiler stays
« Reply #31 on: November 03, 2016, 06:32:42 PM »
hi everyone
just thought i would show how far i have got, i soldered the front on, carried it down stairs to cool, then put in the pickling acid, i soddin droped  it in the garden on the concrete, :hammerbash: not to much damage, only it landed on the joint at the front so i took it back up stairs and resolderd the joint . if i ever make another i will make sure i let it cool where it is stood.  :'(. oh yes i was ill after i had solder it, felt like i was getting the flu, could not stop shaking and my breathing was screwed up and was frozen cold. lasted for about 2 hours,  will get a mask when i do the back end and in the shed. wifes doing her nut i burnt the blinds :censored:. i would have done them both at once but i didnet order enough solder :hammerbash:. need to buy a proper gauge.
 
thanks dave.
« Last Edit: November 03, 2016, 06:35:54 PM by daveclm »

Online Jasonb

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Re: boiler stays
« Reply #32 on: November 03, 2016, 07:34:43 PM »
You need to do it in the open or at the very least a well ventilated shed is OK for small bits. You will be burning up a lot of oxygen and making lots of CO2, if not it could be you that dropps on the floor.

Looks a good job so far.

J
« Last Edit: November 03, 2016, 07:38:14 PM by Jasonb »

Offline daveclm

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Re: boiler stays
« Reply #33 on: November 04, 2016, 10:14:09 AM »
hi jasonb

i wont be doin that again in a hurry. im going to be soldering  in open air next time.

cheers dave.

Offline Roger B

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Re: boiler stays
« Reply #34 on: November 04, 2016, 10:27:19 AM »
Beware  :( Some fluxes contain fluorides. The symptoms you showed sounded to me like 'Foundryman's Fever' which is a form of fluoride poisioning.
Best regards

Roger

 

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