Melting PVC plastic can be a very simple project depending on your reason for melting it. If you simply need to melt the PVC enough that it is pliable, a heat gun will get the job done. If you need to melt the PVC to the extent that you can mold and shape it, you will need a double boiler. Try to keep the heat source at a right angle to your sheet of plastic/plexiglass. If you turn your heat source as you pass across the acrylic, the heat won't be evenly applied across the entire width of your sheet. While you are applying even heat along the bend line, press gently upon the sheet of material you are bending.

These 100g bags are full of ivory-colored polymorph plastic beads with a low melting point of about 60°C (140°F). Heat up some water with a kettle or microwave, then dump the beads in. They'll turn clear and start sticking together into a wax-like blob. You can then knead, mold and shaped the blob by hand and left to harden. Once hardened, it ... Basically the sheet is secured into the frame with some screws, heated in the oven and when reaching the soft temp placed over the mold. A vacuum sucks out all the air and forms the sheet perfectly onto the mold. Works the other way around too if you want to use pressure to work the plastic against the inside of a mold.