Figured I would share the first furnace I've built. Need to scale it down a bit for melting/foundry work. Panels are 4x8(mostly) with 2" ceramic board insulation on the inside. Ran out of panels, used steel mesh and 2" kwool, wrapped in welding blanket. Man in the pic is 6ft tall for some scale. Used 16 NG burners to heat to 400* and maintain while welding. Made 4 of these to help get the temp up around 1100 for stress relieving. Tossed 3 skids worth of lump charcoal in to help maintain those temps. The frame is close to 400k lbs. The building it is in was just a giant portable hut. Temps dropped as low as 40* in the hut. Wad quite the challenge for sure. But it all worked out. Now I just have to figure out how to build a smaller version for actually melting metals.