Kraitok

North State, thanks for the rough idea, that actually helps a lot! Rough estimate, but that should put me in the 700-750 ci range using 2 inches of insulation. I was hoping to get to the 250-300 ci neighborhood. I suppose there are several potential options, starting with the obvious of just using about half the tank. Going with a third layer of kaowool insulation would potentially be an option. Doing a mix of both (maybe a thicker roof and floor both for insulating purposes as well as to remove volume) might be pretty viable too, although I'm not sure if that would force the burner too close to the floor and cause major longevity issues / headaches. Luckily there is a wealth of knowledge on this forum, and folks that both understand the science and the practicality of what newbies like me are after! I'm not sure on proper forum etiquette so I'd be happy to delete this if needed, but does anyone with experience have input on this? I've never used a forge before, just been interested in learning my whole life (dad was a ferrier). I'm not trying to forge a claymore, but having the ability (perhaps not the skill haha!) to make something bowie knife sized would be nice. I'd also like to be able to forge weld with a weld executed 3/4" Frosty T burner.

tinkertim, great idea with the fire brick to reduce volume! I'm in the research phase of building my forge, but have an air tank my dad is giving me to make it out of. I suspect that due to it's length (I'm picking it up tomorrow and will measure it then) I'll either need 2 burners or another work around in the build phase so I have ample heat. That said, once I can take a few measurements I'll have a heck of a lot better idea.