In researching propane burners (which in itself is a fun persuit, at least, when you keep you fingers away from the flame :), I've wondered upon other ways for the venturi and flare. A few days ago I cast some ZA-12 in a conical shape and pounded some brass tubing down over it, to stretch the end. This forms a pretty good flare, but is utterly useless on steel, because all the tubing I have (EMT, water pipe) is welded and it splits very early at the seam, even when orange hot. (Naturally, the peg also cools the metal very quickly - I can only get maybe 1 or 2 strikes against it before needing to heat again.) Any ideas around this? And don't say hydroforming damnit, I can't do that! ;)
I'm not opposed to forging, but I don't have any stake-ness to work this kind of inside surface against.
Tim
-- "That's for the courts to decide." - Homer Simpson Website @