The plans said to put aluminum sheets in which makes sense but that stuff is expensive to coat the entire box! Then i read in another post to use heavy duty aluminum foil but isn’t that going to tear when i put a keg in? I’m generally confused on what to cover the inside of the box with.
Answered my own question. Either use steel or you could get flashing. I saw rolls of flashing which are plenty thick at lowes for like 30 bucks. I went with steel sheets from lowes which were about half the price of aluminum.