PSA: Stop using body filler on plastic bumper covers

Had a guy bring in a 2017 Civic last week where someone slathered 1/4 inch of filler on a cracked rear bumper. It was already chipping off after 3 months. You cant just fill plastic like metal, it flexes too much and the filler pops right off. I see this at least twice a month from backyard jobs that come into my shop. How do you guys handle repairs on flexible plastic parts?

2 comments

2 Comments

veram991mo ago

2014 Accord here. Saw a guy use house paint on a front bumper once. Looked okay for a week then peeled like a sunburn. The problem is people think all paints bond the same. Plastic needs flex additives. That Civic guy probably used regular bondo from an auto store. Tell him to try 3M flexible repair or at least a plastic welding kit. Cheaper in the long run than redoing it every few months.

violamurray1mo ago

Yeah, you nailed it. People think paint is paint. It's not. Plastic moves and flexes with temperature changes and regular bondo just cracks right off. I've seen guys use spray cans meant for metal bumpers and wonder why it's flaking after a month. The 3M stuff is solid but even just using a proper plastic primer makes a huge difference. Honestly, if you're too cheap for the right materials, just leave the bumper scratched. It'll look better than a peeling mess.