I used 3/4" pine for the sides, 1/2" pine for the main panel the rubber was mounted in, and a little MDF to back some of the inserts cut into the various sides. I also used some 2" x 2" pine to make blocks to frame out the sides and front panels, better distribute the weight, and as mounting points for a french cleat. The finished full size HiC weighed in at around 60 lbs and was pretty easy to get up high on a wall with some scaffolding and 2 friends.