I may have found some heavy walled pipe.
this stuff is about 8" in diameter and about 1/4 - 3/8 in thick. (can't get close enough to measure, yet)
I am thinking of one for smelting small lots, and perhaps one for casting.
they should be just the right size to mount a stove circular element underneath. or to sit on a propane burner
Just wondering others experience at the depth to make one. I'm thinking 1-1 would work well...