Ghostbaits,
I have been working on this problem and I have come up with something that seems to be working. I used the candle molds, 4 that are two inches in diameter and one that is 4 inches in diameter. I use the ones with the thick walls. After plugging the hole in the bottom with a metal screw I poured about a 1/2 inch of sand in the bottom of an old sauce pan. I then arranged the molds in the pan and poured sand around the molds to 1/2 inch of the top of the pan. I then place the pan with the molds on a standard hot plate, The sand holds the heat and distributes it up the sides of the molds. I have been using it for a couple of weeks and have not burned any plastic, but you do have to keep topping of the molds.