I picked up some scrap 3/4 inch styrofoam insulation from a local house being built. I lined my melter walls and bottom with pieces of this and it really increased my melting times and temps it will melt in. My melter will hold 2 deeps side by side and it is deep enough to stack them 3-4 deep for a total of 6-8 deeps at a time. I have yet to nfind a day that if the sun was shinning it wouldn't melt the wax and melt it quite quickly.