For the forge body I managed to source a 5 gallon air compressor from a garage sale for $10. I took the motor, compressor, gauges and fittings off and put these in my scrap bins. The tank is perfect at 10" in diameter and about 17" long. The mounting plate for the compressor and motor will make a nice base for the forge.
Next we'll put the insulation and refractory cement in the forge.
Something you may want to think about at this stage is if you want to use the forge as a foundry for melting metals. This is one idea I came up with: