re: I just made a Mini Forge!

That's a good question. Yes I put a 4" long x 1/8" thick x 1/2" wide piece in. 15 minutes went by and the metal still was not red hot. It was hot but not at a point you take it to annealing. There was fair amount of smoke as well. I realized that the thickness of the Plaster of Paris was not fully dried yet. Still cool to the touch perhaps damp. Also it seems to me you can't just lay the piece in there and expect it to get red hot all around. The side that's against the Plaster of Paris is protected. Anyways I then held the cooled down metal piece in there again in the center of the chamber with a pair of metal tongs and it got red hot in under a minute. Real fast. A bit of experimenting as to what can or can not be done and learning from it is in order.