one sheet of melamine, cut into 5, 36X18's
one sheet of plywood, cut into 1, 32X36 and 2, 18 1/2X32's
i used two cd's as spacers which left me with about 5 1/2'' potruding from the top, which actually leaves me barely enough room to make one more 6qt shelf, but you would need to buy another sheet of melamine to get the piece
also, the back piece is squeezed in between the two sides, and the plywood i used is wax coated on one side, which i put on the inside of the shelves