OK- I've built the smokehouse. 4x4x8 with a 4 x12 roof pitch (shed type). For the roof I used steel R-panel, which I think will give me some good draft, since the stuff has a 1.5" corregation every foot. Now the only question I have is regarding the firebox. I intend to put it 10' from the smokehouse and run either 4" or 6" pipe for the smoke delivery, but I'm wondering what to use for the box itself. I have at least a dozen 55 gallon drums around here, but don't know what was in them. Two of them I know had SULFOLANE-A in them, which I know is a solvent. Can I safely use one of those those for a firebox, or do I need to go to the expense of new sheet steel?