| Alan,
With regards to your 'dismal failure' scenario.
Rest assured, this is the way to go for just a couple of end flanges. Many thousands have been made that way, a few of them by myself.
All you have to remember is keep the metal soft, if you find it is starting to harden in any way at all, it needs annealing again. Four or five times is about the norm. It should bend and form just like lead sheet, with no 'Nora Batty' wrinkles.
The bit you have been forming will not be seen as it will be inside the boiler, so a few hammer marks won't matter.
If you want the flanged ends on the outside (like 'toy' boilers) then yes, you need to press or spin them to give you the nice edges.
If you are using standard plumbing pipe for your small boiler, then plumbers merchants should have pipe cappings pre-made, but I think they only mount on the outside and will need a bit of the flange removing as they are rather long. But I may be wrong on that score, you would need to check if they do internal ones as well.
As for pressing, speed and pressure is the order of the day. You have to get it done as fast as possible before the metal has time to work harden, otherwise you might find you will get half way thru the pressing and have to disassemble it to get the part out again to reanneal.
I hope that this hasn't put more confusion into the pot.
John |