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Wavy paint on fiberglass bumper


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Howdy,

Back in May I got rear ended by someone and I just got the car back last Friday (don't even get me started.....). I wanted to post to see if anyone could give me some insight into a discussion I had with the body shop about my aftermarket bumpers. I actually replaced the stock bumpers a few years back with a fiberglass kit from Better Bodies Motorsport out in CA. Back then the body shop (a different one than the one I used for this job) also took forever to get the car put together but when I got it back I was pretty happy with the results.

Unfortunately, this time around I'm not as happy. Don't get me wrong, in general the car looks fantastic (especially after not having it for 3 months), but the paint job on the aftermarket bumpers is a bit wavy. What the body shop is telling me is that due to the nature of fiberglass when the parts go into the oven to bake it causes the air pockets in the product to move and create the "wavy" look. He said the only real thing to do is put on tons of clearcoat and even that will not solve the issue 100%.

I'm no paint expert nor am I a fiberglass expert. All I know is that the last time someone painted these bumpers there did not seem to be as many waves in the paint. If anyone can provide me with insight I would appreciate it. I just want to know if I'm unintentionally busting the balls of the body shop on something that nobody can really make perfect, or if they are trying to pull one over on me because the insurance company only paid them a certain amount and they don't want to put in more time, or if it is something in between. Thanks!

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The whole story is BS IMO! First, the bumper covers are not made of fiberglass but a semi-rigid thermoplastic made of polyolefin-type (TPO). Most likely the wavy marks are from poor sanding techniques that leave the suface uneven. This is very easy to do when you consider the soft nature of the plastics and is a direct result of poor training and knowledge of repairing Thermoplastics. Once the damage is done it will be very difficult to restore the original surfacce of the bumper. The major issues with aftermarket products is not the surface finish but the accurate fit of the parts. My advice would be to contact your insurance company and tell them the servie is unacceptable. I went through this when someone ran into my Honda Civic and I forced them to use OEM parts AFTER they used the non-OEM and it looked like A$$.

Hope this helps, Tom

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The whole story is BS IMO! First, the bumper covers are not made of fiberglass but a semi-rigid thermoplastic made of polyolefin-type (TPO). Most likely the wavy marks are from poor sanding techniques that leave the suface uneven. This is very easy to do when you consider the soft nature of the plastics and is a direct result of poor training and knowledge of repairing Thermoplastics. Once the damage is done it will be very difficult to restore the original surfacce of the bumper. The major issues with aftermarket products is not the surface finish but the accurate fit of the parts. My advice would be to contact your insurance company and tell them the servie is unacceptable. I went through this when someone ran into my Honda Civic and I forced them to use OEM parts AFTER they used the non-OEM and it looked like A$.

Hope this helps, Tom

Hey Tom,

Thanks for the reply! Actually, I made the decision a few years back to swap out the OEM bumper covers with aftermarket covers. I understand that the OEM is a urethane but the aftermarkets that I chose are fiberglass. The questions is with that situation should I expect wavy effects on the paint? It's not something most people walking by the car would notice (you can't even tell when you take pictures of it), but when you look at the reflection of a sign in the paint job it is perfectly smooth on the body panels and turns wavy when it hits the bumper. With that additional clarity, does that change your option about the situation?

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Ah, that explains the FG part! Most high end shops will wet sand the clear coat with 2500 grit to remove all the imperfections and then buff out with mirror glaze or similar polish compound. If done correctly, the relections from a stop sign etc should be wave free with crisp clean edges. It takes some time but the end results are well worth it. The average person wouldnt note the difference but if you have an eye for detail you will pick it right up.

Regards /Tom

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