i chose the 1/2" box for a couple of reasons,...
1.) the thermal mass! Once that 1/2" plate heats up it's a lot easier to maintain temps in the rest of the pit, it also works in conjunction with my warmer/oven in keeping heat loss to a minimum, increasing efficiency and fuel economy. I'll recoup the money spent on the upgrade by saving on cooking wood expenses.:wink:
2.) durability! It's hard to do but even 1/4" plate can warp with high heat and i've seen doors become hard to close and intake dampers become difficult to adjust,... My 1/2" box will never get hot enough for any of that to happen. There is also the corrosion factor to consider,... Rust in the firebox is inevitable and i know that my great grand-kids will be able to use my pit one day without having to replace the firebox on it.:-d