Originally Posted by teamextreme
Sounds like a couple recommendations for plywood over steel for the interior rear panels. Plywood would definitely be cheaper, easier to work with, easier to procure, and potentially sound better, but I'm still concerned about weather resistance and mounting. I'll be herculining (or similar) whatever we use, so the outside will be ok, but do you paint or herculine the backside as well? Also, how thick do you use? Seems like using thick enough for strength would end up causing fitment issues inside, ie; interference with seats folding down, etc. I would guess 3/8" or 1/2" would be needed, but that seems awful thick to be installing down the sides.
I used 3/8" and covered it with Home Depot gray indoor/outdoor carpet, also wrapped around the edges so it was pinched by the install. No squeaks, no rattles. I also used stainless oval-head phillips screws with oval-head washers, and nylocks inside. Stays put, looks nice. Also cut in some access doors for side panel storage, and used some slick flush pushbutton cabinet latches my wife recommended (she is a woodworker). I will show them to you sometime.
I did not herc the inside, but I generally protect the rear with a softtop anyway. Hercing both sides would certainly seal it. Use outdoor rated plywood.