Source for copper tube

[firebird]

Hi

I have been trying to source a piece of copper tube 2 1/2 inch diametre 10 swg (1/8) for my portable engine with no success at all. I have tried all the usual suppliers and just about exhausted all the listings on google. Anybody got any ideas.

Cheers

Rich

 

[GWRdriver]

Rich,
That's quite an odd combination of dimensions, even for the UK. The best we will be able to do here in a standard tube will be 2.625"OD x .095" wall. Somewhere I know heavier walled copper "pipe" is available because I have a few odd pieces of up to 1/4" wall and IIRC these came from a recycling yard in eastern TN where material from nuclear power plant construction was occasionally disposed of. I would guess refineries or nuclear subs or such exotic places might use it also, but I have never seen a listing of sizes or sources.

 

[gabby]

Hi there, have you tried anyone in the refrigeration busines, some of the larger commercial companies are your best bet as they use the larger dia pipes for large A/C installations or even supermarket refrigeration.
I know this as I am a refrigeration engineer here in New Zealand and I have some bits I have snaffled over the years.
Cheers.
Graham ;D

 

[doubletop]

Rich

What pressure are you aiming for? 16swg is fine for 3" tube and 80psi If you were to do the calcs for 2.5" 10 gauge I'm sure you'd be way up above that.


Pete

 

[Blogwitch]

Rich,

It looks like you might be aiming to have a tube rolled for you. I would offer to do it for you normally, but as it is, I can't even get my own stuff sorted.

But I am sure that if you asked nicely, someone could do it for you, then it would just be a matter of getting the seam joint riveted and silver soldered as per regulations, it's not as hard as you imagine.


John

 

[firebird]

Hi Graham, I have tried many companies and suplliers but to no avail. It seems I'm the only person that needs some of this size : :

Pete, the type of boiler I'm building uses the 2.5 inch inside the 4.25 inch as the firebox therefore the pressure on the 2.5 is external not internal also I would like to coal fire it. I have been advised that the thicker wall is needed for external pressure and is also better for coal firing.

John, I was wondering if that would be possible. I can source 3 inch swg tube and thought it might be possible to cut out a section and re roll it to make 2.5 inch.??

Cheers

Rich

 

[tel]

John, I was wondering if that would be possible. I can source 3 inch swg tube and thought it might be possible to cut out a section and re roll it to make 2.5 inch.??

That's certainly doable - you won't want to cut any out tho' - just slit it and re-roll.

 

[Blogwitch]

Rich,

I think what Tel is aiming at is that the overlap can be riveted and silver soldered up to make your joint.

Dead simple, and that is how boilers used to be made before you could obtain tubes of the correct size.

I have only ever made one boiler like that, many years ago, for a chaps' loco. It was tapered front to back with a dovetailed joint and a riveted on backing plate. Not a job I would like to do nowadays, but still doable.


John

 

[lordedmond]

thats how you do a tapered boiler see my avatar

although for UK regs you do need the butt strap to be on the outside ( the inspectors god bless them like to see it ) if you put it on the inside they will need to inspect it at a early stage , also when it is on the in side in will impinge on the tube space.

why don't you re calculate the boiler dims to suit an available size ,stay spacing etc it will save you time and money


why 80psi 100 psi is better more expansion of the steam to do work

the boiler in the pic is on test for 100 psi SWP note the test is at 200psi the thing is about 100 llbs.


Stuart

 

[firebird]

Hi all

they say a picture is worth a thousand words so here is a picture of the type of boiler I intend to build. Mine will be based on this design but not an exact as per plan copy.

I am using 4.25 tube for the boiler, slightly larger and I intend to make it longer as well. Note that the 2.5 tube in question is not the boiler tube but the firebox. I can't go any larger as this would leave in sufficient space for water above the firebox, likewise smaller would look out of proportion.

Here is a link to where I am so far with this project

http://www.homemodelenginemachinist.com/index.php?topic=16772.0

I haven't made much progress lately, decorating season is upon me

Cheers

Rich

 

[Jasonb]

M-Machine list 2 1/2" x 10swg copper, page 11

http://www.m-machine-metals.co.uk/mm/website/mm_cat_2011.pdf

 

[tel]

I think what Tel is aiming at is that the overlap can be riveted and silver soldered up to make your joint.

Yes, or form the excess into a castellated joint.

 

[firebird]

Hi

Jason, this is a case of great minds think alike, I have just 10 minutes ago sent them an e-mail to see if its in stock.

Tel, I think I know what a castleated joint is. Is there a recognised method/size of doing this type of joint?. Does it still need the extra strap fitting on the outside. I'm tight for space/clearance at the bottom, only .25 to play with so with a strap I would have to move the firebox up a corresponding amount which results in less water space above. Is it because the joint line is increased in length that makes the castleated joint better?

Cheers

Rich

 

[Jasonb]

I had a feeling castellated joints were out of favour for barrels but still OK for extending the depth of the firebox wrapper if opening it out from the main barrel tube but could be wrong.

J

 

[tel]

Castellation should be fine on a small boiler such as this one. You should not need a strap over it. As far as the size of the castellations I think you would just have to juggle it to fit your particular boiler, taking into account the amount of overlap you have available

 

[modelman1838]

When I built my Sissons boiler I rolled the firebox up and simply butted the joint and fitted a butt strap on the outside at the bottom. I agree that you need thicker material for external pressure but the joint itself is less stressed and should`nt need anything too fancy.
Hugh.

 

[firebird]

Hi

Thanks Hugh

Cheers

Rich

 

[firebird]

Hi

At long last I have sourced some 10swg tube

From the place Jason posted this link to

http://www.m-machine-metals.co.uk/mm/website/mm_cat_2011.pdf

Its the first time I have dealt with them and the service was excellent, ordered Tuesday arrived Wednesday. The decorating is getting close to the end so I should be able to get back in the workshop soon and get on with the boiler.

cheers

Rich