Have you ever had to throw something away or replace it because it was made of plastic and was broken? I will show you how to repair many plastic parts that have been broken using nothing more than an ordinary hot glue gun. Did you know that hot glue is nothing more than plastic? Your basic hot glue gun is a plastic welder, and with it you can repair many plastic items as good or better than new.
Step 1: Understanding Plastics
There are many different kinds of plastics. Some of them are easier to repair than others. Many plastic parts are made from a plastic called ABS. It is a hard, somewhat brittle plastic and is easily broken. Small pieces with clean breaks can often be super-glued much like reattaching a handle to a tea cup. For larger pieces or for more extensive repair, hot melt adhesive can be used.
Hot melt adhesive or simply hot glue is really a plastic. It is very sticky when molten and is called an adhesive for that reason. It is specially formulated for adhesion. Nevertheless, it is still just another kind of plastic. It is softer and more flexible than ABS plastic. It is a very useful plastic on its own and can be used to make all kinds of things. Don't be afraid to experiment.
In this instructable, I will demonstrate how to not only repair a broken piece of plastic, but even to do some rudimentary molding to fabricate plastic parts. The piece I will be repairing is a large cover for an air handler in a automobile.