Colleague said I should stop using filler on plastic bumpers and I'm torn

Ran into a guy at the NAPA in Phoenix last week who told me he never uses filler on plastic bumper repairs, says it always cracks after 6 months no matter what you do. He swears by using plastic welding rods and flexible primers only, but I've been using filler on bumpers for 8 years with maybe 1 call back the whole time. Who's right here or does it depend on the type of damage?

2 comments

2 Comments

felix987d ago

Honestly that guy at NAPA was right about one thing but wrong about the other. Plastic filler cracking usually happens because people don't use the right flex agent mixed in, not because filler itself is bad. Tbh I've been doing this for a while too and the trick is getting the right 2-part flexible filler made specifically for bumpers, not just any body filler you have laying around. Ngl though he's spot on about the plastic welding rods being better for big structural damage like tears or cracks that go all the way through. Filler works fine for shallow scratches and gouges where you're just leveling out the surface, but for anything deep you gotta weld it first then fill over that if needed.

wren_jackson7d ago

Wait, does that flex agent work the same across different types of plastic like TPO vs. polypropylene? I've seen guys swearing by specific fillers for each but never got a straight answer on whether it matters. Seems like half the problem is people just grab whatever flex additive off the shelf.