Quote Originally Posted by WingedWolfPsion View Post
I'd go with plywood, and it doesn't have to be very thick--you're going to line it with heavy insulation foam board, right?

I'm experimenting with making one out of just foam board, with 2X3s for a frame.
I was thinking plywood and yes I will be also adding insulation foam too. I was wondering if the plywood would warp? Anyway any ideas of the fans, should it be on all the time or set with the thermostat so it only goes on with the heat tape.