A while back, I built a forced air forge for myself. I wanted one in order to reach forge welding temperatures in a gas forge.
I then drew a face on it, and named it. Meet George the Forge.
George the Forge is relatively easy to build. First, I found an old air tank at an auction and picked it up on the cheap. I cut off each side, and placed a couple of fire bricks down for a flat surface and lined the inside with 2" kaowool. I then coated the kaowool with ITC-100, a refractory cement that helps with forge temperature and is resistant to flux.
I picked up a bunch of black steel pipe from the local hardware store. Mostly 2", some 5/8" for the gas line coming in, and a 12" piece of 1-3/4".
I also picked up 1x 2" gate valve, 2x 90 degree 2" elbows, 1x 2" T, and a 2">1-3/4" reducer.
After putting George together, here is how he looked, without his face (which I kept once I cut off the end).
The gate valve controls air flow into the cavity. What isn’t shown very well in the image here is the T on the vertical part of the 2" goes to a 5/8" pipe, that flow is controlled by a needle valve and then goes to the propane tank.
I haven’t measured temperature inside, mainly because I don’t have the means to, but it does get to forge welding temperatures! Anyways, it was a fun project.