I'm going to talk to the guy who sold me the mold ... but maybe you all have some ideas. I bought the 18 bar tray and the guy who makes them told me that it would be fine for M&P. For this "batch" I used only two center slots, and taped around them to prevent the melt from running all over the tray. That worked fine. But I'm very nervous about using the entire tray. When I poured the fluid into the mold, it was almost as thin as water, and I know for a fact that the tray doesn't hold water. Will the melt spill through the mold, or will it quickly cool, harden and "seal" the bottom? The other thing that happened was that the center of the bar is much thinner than the edges. It looks like capillary attraction or something... the edges creeped up the sides of the mold (I poured one inch of melt into a 1 5/8" mold... maybe you just can't do that?). But even without that effect, the top of the bar is definitely concave. Any ideas? Thanks in advance.