How to Melt Plastic Bottles for Molding | Sciencing
Pour the melted plastic into a mold using a wooden stick. Allow the plastic to completely cool before taking it out of the mold. Making Your Own Plastic Molds. To make your own molds, try forming clay around one half of an object, then the other half. Place the two halves together, leaving a hole in the top where the plastic will be poured.