Hi Henry,
It appears there are no replies to this one? So I'll try and help?
First - and this is Law in many places - but not all...?
To weld pressure vessels, including boilers, in many areas you MUST be a certified welder using certified material, and certified designs and checked and certified welds at all stages.
(What a nuisance you may say?).
But, like making guns and bombs, as long as you don't cause a nuisance, no-body knows what you do in your own home, and you don't kill/maim/hurt, etc. someone else or their property, then in a "free world" you can do what you want. It's just whether or not you feel bound by the appropriate laws and rules (for insurance? etc.) wherever you are.
I can weld, I could make a steel boiler. But I don't, because I could never get it certified in the UK (I am not a certified welder for steel pressure vessels), so could not run it in public. For my own use (in secret, in my garage) yes, I could use it, but that is too restrictive for me to want to make a steel boiler. Though in my model club, some do... and get certification and satisfy the insurance requirements, and use in public too. (e.g. 1/4 scale traction engines).
So I make copper boilers, silver soldered, and even convert "useless" old copper boilers into good working boilers, all be it usually for different purposes and at lower pressures than the "dangerous" operating pressures they had been subjected to in an earlier life. e.g. By "Dangerous": I had a boiler that had been used at 60psi, but - according to normal calculations - was reaching the limit where it would crack a joint or deform permanently (possibly not bursting) at about 80psi. I.E. a factor of safety of 1.3, not "8" as required by UK regulations, guides, and common sense of most operators. But adding some stays to strengthen it, it recently passed design examination and initial leak testing (without deformation) for 30psi operation.
All I am saying, is simple.
Boilers for steam generation can be dangerous, so get it right by checking what you must do with local experts - so you stay safe, stay within the law, stay certified, and cover your A##se with insurance.
If you want proper advice about your particular size/application for a steam boiler, please ask again? - With details of the engine size, pressure and what you are powering?
Safe steaming sir!
K2
