Enough for a cutting board and maybe an oven pan or two. I was going to back it with plywood. Then I thought what about polycarbonate? I knew it had good impact resistance but found out it also has good heat resistance. Plus, 1/4" has as much sound deadening as and inch of wood. Why not be able to see the engine running? I will now have to fix the belt dusting problem for good. Little kids will love this!
The ply panel I built the doors out of came out of the local boatbuilders dumpster. Hence the paint on the inside.