naw, i was being serious, thats why i said something about email the other day.. a thin steel should be ok for flashing, but a plywood enclousre would probly need a couple of fires in it first to season it, right?
also, a steel fire pot should be ok..i think.
We lined the lower interior of ours with the .020" gauge SS roofing flashing. That keeps the radiant heat direstcly off the wood sides and will not burn the frame. Yes we have a hardwood plywood frame that has been "seasoned" many many times over. But the heat your smoking at is lower than what will burn the wood.
You have to understand the basic physics of a smokehouse; you have a heat source in the bottom that is pushing heat to the top, rising vertically. The walls contain it but the flow is from a bottom front vent to a top back vent, so your heat, and likewise your smoke, is contantly travelling upward. You're containing the heat but allowing it to flow in a regulated manner up and out; it's not staying still and overheating the sides. Yet, your temp is holding at 250°-280° in the center of the upper chamber as heat rises and that's where you want it at.