New research from Polyvance shows that the strength of some plastic welds can be compromised if they weren’t welded at the recommended temperature.

It’s important to weld plastics at the appropriate temperature according to the type, Polyvance said. The melting points, which shouldn’t be surpassed when welding, are:

Polyvance recently performed instrumented peel tests to demonstrate that the strength of some plastic welds will weaken if welded at temperatures that are too high.

For example, the testing proves that PVC samples welded at 1,300 degrees Fahrenheit were 35% weaker than samples welded at 850 degrees, Polyvance said. The welds performed at 850 degrees were 55% stronger, on average, than those welded at 1,300 degrees.

In a YouTube video about the testing, Polyvance says “hotter is not always better.”

A complete list of plastics melting points available through Polyvance with recommended nitrogen welder temperature and airflow settings can be found here.

Database Enhancement Gateway Administrator Danny Gredinberg told Repairer Driven News that melting points, welder settings, and plastic repair procedures depends on the OEM; some say it can’t be done.

“It’s not always in terms of plastic welding but overall the process of repairing plastic bumpers depends on the type of damage,” he said. “There are also OEMs that specifically say no repairs are allowed to bumpers/plastic with ADAS systems (Nissan, BMW, Subaru, Ford, GM etc.).”

I-CAR, along with Polyvance, has also shared guidance on plastic repair as part of I-CAR’s Repairers Realm web series.