1. First we identify the plastic to be welded by using the floating water test. Using a small piece of plastic taken from the component to be welded we drop it in a container of water. If it floats then the plastic is likely to be Polypropylene, or Polyethylene. If it sinks then the plastic is likely to be PVC, ABS or Polycarbonate.

2. We can then use the adhesion test with welding rod. By heating up the welding rod, and the plastic sample to be repaired, press the welding rod onto the plastic part by applying hot air. Push the welding rod onto the plastic part to begin plastic weld. If the cooled down rod stays firmly in place or can only be pulled off with difficulty, both plastic materials are the same.