When working with plastics they are very sensitive to the proper temperature and proper matching of the base material. The best way to determine the base material is to purchase our RTK Rod Test Kit that has a small sampling of the most common materials. This materials include ABS PVC HDPE LDPE PP and PLA.
The best way to determine the proper temperature is to refer to our temperature chart. The material should flow like a very viscous fluid or oil similar to wax. If you see black and burning you are too hot and need to reduce temperature by 20-50c.
Happy Welding!