Changed my mind about using filler primer on plastic bumpers

I used to swear by using regular primer on plastic bumper repairs because it was cheaper and I figured it'd bond fine. Last month I was fixing a 2017 Civic front bumper at my shop in Toledo, sprayed my usual stuff, and three days later the customer came back with peeling paint all along the edge. I had to redo the whole job for free, lost like $150 in materials and a full Saturday. That mistake convinced me to finally try that adhesion promoter and flexible filler primer I'd been ignoring. The second time around the paint stuck hard, no lifting at all, even on the flex points. Now I won't touch a plastic bumper without that stuff, it's just not worth the risk. Has anyone else had a similar fail that made them switch up their process?

2 comments

2 Comments

charles_coleman23d agoMost Upvoted

I hear you on the adhesion promoter working better, but I see it a little different. I've been doing bumpers for years and I still use regular primer most of the time, just gotta rough up the plastic real good with 80 grit and clean it with the right solvent. I had a job where the flexible filler primer actually cracked on me in cold weather, so now I'm pretty picky about when I use it. I think a lot of the peeling problems come from skipping the prep steps or not letting the primer cure long enough. If your system works for you that's great, but I'm not convinced you have to switch for every plastic job.

briancampbell23d ago

Rubber content varies a lot between different plastic parts too.