Before there was the Damascus Blade, there was the Charcoal Forge...
Me and a buddy built the frame in one afternoon, mostly out of 2x4s, 1/2" plywood, angle brackets, and some ABS pipes and joints. There is a hole drilled into the center of the plywood board and the ABS pipe fits through it to provide forced air which will come from the bottom via a hair blower. (ABS turned out to be a bad choice as it melted after a while when I turned off the hair dryer, it was later upgraded to brass sheet metal pipe for the top half)
I then folded some sheet metal to make a box to line the inside of the forge, so that any spark will not set the wooden frame on fire (a forge made out of wood has to take every precaution possible). Inside the sheet metal box I placed several firebricks to lift up the combustion area from the base (away from the wood and ABS). The bricks are secured by refractory cement. After the cement has set, I welded a piece of sheet metal into a conical shape and that is the combustion chamber. I poured the perlite (all 5 bags of them at $10 each) around the combustion chamber. The perlite will help insulate the outer frame from the heat of the combustion chamber.
All done. There is some "shelf space" on the bottom of the stand. The hair blower can be easily removed from the ABS pipe. All the metal sheets have their edges folded back, this strengthens the metal and removes all the sharp edges.