I am sure you have already looked over a number of other RF builds here on this site and you will notice that there are very few that are the same. Similiar, but not the same. The same thing goes for thickness and or gauge of steel on the pit builds. No doubt, the thicker the steel, the higher amount of heat retention you will have, but it is not necessary. Most of us have built pits with what we have, what is readily available and affordable. I would prefer it to be thicker, but I think you will be fine with a 12 gauge cook chamber, as you begin to cook with it, you'll learn the ins and outs of your pit and be able to handle it as well as those built with 1/4 or 3/8 steel. 12 gauge would be just shy of 1/8" thick, a bit more heavy duty than the typical store bought smoker, but obviously not as thick as a propane tank. My main chamber is 3/16" thick, and while smoking at 250, I can put my hand on the chamber without much of a burning feeling. 1/4" on the firebox is a good choice, the thicker the better there, because of the high levels of heat involved with the fire, thicker will last you longer. As far as the flow plate, thicker is better as well. This will help eliminate the hot spot at the firebox end of the chamber for sure. I used 1/4 for the RF plate and at grate level, the firebox end is still 15 degrees hotter than the opposite end, even with the 1/4 plate. So, the thinner the RF plate, the hotter the firebox end will be, of course you could double up the steel on that end, kind of like a baffle plate below the RF plate. To me firebox and RF plate are quite a bit more important as far as thickness are concerned than the chamber.
X2.
