Some plastic welds can be destroyed at temperatures that are too high, according to recent instrumented peel tests performed by Polyvance.
Different thermoplastics can melt at different temperatures as a result of different molecule chains. While ABS and low-density polyethylene both melt at the “relatively low temperatures” of 221 degrees Fahrenheit, nylon in comparison will melt at a much higher temperature of 516.
The findings affirm how critical it is to set a plastic welder to the correct setting depending on the type of plastic being worked on. PVC plastic welded at 1,300 degrees Fahrenheit became scorched and discolored in the test. When it was welded at 850 degrees, it showed no signs of discoloration and proved to be 35% stronger.
The strength was tested by “pulling up on the free end of the welding rod and using a tension tester” on two sets of nine samples: one group welded at 850 degrees and the other nine welded at 1,300 degrees, all welded with nitrogen gas.
The 850-degree welds proved to be 55% stronger on average. The average peak load for the 850-degree samples was 60.6 pounds, compared with 39.1 pounds for the 1,300-degree samples.
