Two more cents worth on bending mild steel tubing. Trying to bend two 90
degree bends 3 inches apart in 1-1/2 inch by 1/8 inch thick tubing? I
think this may be pushing the envelope a little! That's a 90 degree bend
on a radius equal to the diameter of the tubing. Very Very Difficult. But
that being said , I would suggest filling the tubing with a product called
"CerroBend" (I think) which is specifically made for this purpose. It is a
metal somewhat like lead solder, but melts at below 212 degrees. Having
the pipe filled with metal should make for the least distortion when
bending, but still use a mandrel if possible (although I doubt that you can
find one with that sharp a radius for that size pipe. This is of course
Also if you try to bend the pipe with heat I would suggest that you heat it
cherry red only on the inside 180 degrees of the pipe so that when you bend
it the outside radius will not distort as much and the inside radius will
more easily collaple and wrinkle to take up the extra material. Again I
would do this around a madrel of other form of some kind.
I don't know what this is for, but any chance you could braze the assemble
together from plumbing pieces in either coppper, brass or cast iron ?
Good Luck, I would be curious of how you make out.