Boilers

[Peter Moyes]

I have just joined and have also just started into model engineering. My first project has been to build a boiler in accordance with the instructions contained in that excellent book, Making Simple Steam Engines. I now have a simple boiler can made of copper with a mild steel sheet support cage which is 80mm in diameter and 300mm long and which I have cased in timber planks to provide lagging which is suggested in the book. I have screwed the completed assembly for which I still have to make the safety valve onto a timber base with enough room to fix the actual steam engine when I build that. I am currently making a methylated spirits burner. Now the book says it should be made of brass. I don't have any brass and am making it out of copper and silver soldering the bits together. My question is: Is there a reason why it should be made of brass and not copper or any other material? And, given the size of the boiler, is there a better way of heating the water? Pete mentioned gas, but I wouldn't have clue how to go down that track.
Peter Moyes

 

[Deanofid]

Try putting this in the "Boilers" section. You will probably get more views from the boiler crowd.

I see this is your first post. How about an introduction? The "Welcome" section would
be a good place for that. ;D

 

[zeeprogrammer]

Welcome to the forum Peter.
Is that book actually titled "Making Simple Model Steam Engines"?
That was one of the first books I got.
Have you got some pictures of your project?

 

[SBWHART]

Welcome Peter

Copper is preferred to brass as the zinc in the brass will leach out over time and weaken the boiler.

But it does depend on the size of the boiler and the pressure you intend to subject it to for it to be a safety issue.

Stew

 

[Jasonb]

I think peter is talking of what material for the burner not the boiler as that is already made from copper. I can't see any reason you should not make the burner from copper sheet if you have it though any fittings would be best in brass as its a lot easier to machine.

If you want to fire with gas you need a refillable tank, regulator and would be best with a ceramic burner. Have a look at Bruce engineering for these

http://www.pollymodelengineering.co.uk/

Jason

 

[doubletop]

Peter

Hi; missed this as your first post sorry

My poker burner may do it if you want to use gas

http://www.homemodelenginemachinist.com/index.php?topic=9111.0

You'll see I used stainless for the body. Dave at the club suggested using it and it worked well for me. I've done brass and copper burners also with reasonable success.

Or there's Firebirds spirit burner if you want to go that way.

http://www.homemodelenginemachinist.com/index.php?topic=9262.0

I just use a camping gas cylinder from Mitre 10. The key is the gas valve and the jet size, I've no idea on the theory is but my poker burner worked first time. However, when I was down at the club at the weekend getting my Rob Roy boiler tested Dave and I got into a discussion on burners and he was getting into some serious theory on gas flow dynamics on the blackboard. So there's help there if needed.

Perhaps a few pics of your boiler would help us see what you are trying to do.

Pete

 

[cidrontmg]

Hi Peter,
Using copper instead of brass for the burner is mostly a cosmetic issue. Copper is far easier to scratch and dent than brass (brass is harder), copper tarnishes easier,
and if you want to polish (or blacken) the thing, brass would be the better material. But in functionality, no difference. Just about any "usual" metal will do.