These days, we’re all looking for ways to expand our services. For those who want to include plastic welding into their repertoire, know that many of the principles are the same as welding metal. To start, you need a good joint prep. You’ll also need the right heat and air pressure, plus the right filler (although some forms of plastic welding such as ultrasonic welding may not need any fillers). Lastly, as in metal welding, plastic welding requires that you have the right tip. Just like many kinds of metal exist, it’s the same with plastics. By the way, the word “plastic” is rooted in the Greek termplastikos, which means “fit for molding.”
Plastic falls into two main groups: thermoset and thermoplastic. Thermoset plastics are not conducive to welding because no matter how much heat is applied, they do not soften or melt. A prime example of this is polyester. On the other hand, thermoplastics will melt with heat. Thermoplastics include polytetrafluoroethylene, polyethylene and polystyrene. Polystyrene is used widely in packaging, notably the plastic shopping bag. Polytetrafluoroethylene, or PTFE, is frequently used as a non-stick coating for cookware. Resistant to corrosion, PTFE is also used to make laboratory containers, tubings and plumbing thread seal tapes. Lastly, polystyrene is used to make plastic models, DVD cases and smoke detectors.
Each thermoplastic requires specific heat and pressure to melt. It will be necessary to know what type of plastic you’re welding and its requirements. In general, the best filler is the same material you’re welding. Along with the proper tip, consider also if the plastics being welded together are of different thickness. If they differ, then this will be a factor in whether the final product will be compromised.