Expert: Michael Kakuk - 9/27/2009

Question
I am experienced welding plastic (canoe and kayak repair). The front bumper on our 06 toyota corolla is cracked below the air intake hole.  Is it a weldable plastic and if so what is it? thanks

Answer
David......Bumper covers are made of several plastics, all of which fall into two categories: thermoset and thermoplastic. It’s important to know which type you have to determine how to proceed with the repair. Thermoset plastics can be thought of as a chemically catalyzed process. Part A and Part B are mixed together and injected into a mold. Once set, the part won’t melt with heat...it’s set.

Thermoplastics are dumped into a hopper in pellet form, melted by a heat source and then injected into a mold. Once cooled and set, the part can be melted by a heat source like a plastic welder.

You can do this in most cases by a float test. Most olefin bumper covers are lighter than water. Cut a sliver of plastic from the backside of the cover and make sure it’s free of dirt, paint and undercoater. Place it in a cup of water. If it floats, it’s olefin or TPO, TEO, PP + EPDM . This covers 80 percent of the bumper covers you’ll repair.

If the crack is small you can use Fusor plastics repair epoxy.

Good Luck