Is there a way to smooth out the bumper trim?

General conversations about BMW E28s and the people who own them.
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Etip
Posts: 56
Joined: Sep 05, 2021 2:06 AM
Location: Seattle

Is there a way to smooth out the bumper trim?

Post by Etip »

The bumper end plastic (that wraps the bumper around the side of the car (US car)) on my e28 is warped. I understand this is pretty common.
Is there a way to smooth it out?
Maybe heat it with a heat gun and put boards on it or something?
Thanks for any help.
Blue Shadow
Posts: 9662
Joined: Feb 12, 2006 12:00 PM
Location: SE PA

Re: Is there a way to smooth out the bumper trim?

Post by Blue Shadow »

Glue flat metal underneath
rochareels
Posts: 103
Joined: Sep 28, 2013 12:25 AM
Location: San Diego, CA

Re: Is there a way to smooth out the bumper trim?

Post by rochareels »

I have one that is pretty straight I could part with.
DM if interested… I was wondering the same thing for straightening. How to fix that.

Pablo
BenTomm17
Posts: 96
Joined: Apr 21, 2015 6:02 PM
Location: New Jersey

Re: Is there a way to smooth out the bumper trim?

Post by BenTomm17 »

A friend of mine did the heat gun trick on the top rear bumper surround. Worked for a while but then warped again in a few months.
Mike W.
Posts: 25676
Joined: Feb 12, 2006 12:00 PM
Location: California Whine Country

Re: Is there a way to smooth out the bumper trim?

Post by Mike W. »

I had the benefit of good fortune, finding what was surely a recent replacement, judging by the condition of the surface, let alone the lack of warping like mine was, but, I tried and succeeded in preserving it that way. I got to looking at it and while there wasn't much I could do about it having warped, I saw where it appeared that the attachment screws contributed to things. Tightened down as any sound mechanic would, it inhibited movement, so when it shrunk, it warped. I left the screws loose. Barely snugged enough to stay on. I don't know how long it was before I sold it afterwards, 6-7-8 years, but it stayed flat. Maybe I just got lucky, but it appeared to me giving it room to move helped prevent it from warping. YMMV.
Etip
Posts: 56
Joined: Sep 05, 2021 2:06 AM
Location: Seattle

Re: Is there a way to smooth out the bumper trim?

Post by Etip »

Hey. Thanks for all the replies. Since mine are already warped, I think I'll hit him with the heat gun to smooth them out, glue some metal supports underneath, and then loosely refasting them. I'll take everyone's advice and roll it all into one to see how it turns out.
demetk
Posts: 8429
Joined: Aug 09, 2007 8:58 AM
Location: CT, USA

Re: Is there a way to smooth out the bumper trim?

Post by demetk »

The thin top surface is very susceptible to bubbling if you apply to much heat.
Etip
Posts: 56
Joined: Sep 05, 2021 2:06 AM
Location: Seattle

Re: Is there a way to smooth out the bumper trim?

Post by Etip »

demetk wrote: Jan 24, 2022 10:19 AM The thin top surface is very susceptible to bubbling if you apply to much heat.
Thanks for that info!
vinceg101
Posts: 4485
Joined: Jun 20, 2007 2:40 AM
Location: Los Angeles, CA

Re: Is there a way to smooth out the bumper trim?

Post by vinceg101 »

Rod Paine has a good tip on how to keep it from warping in the future (as part of his page on refinishing US bumpers):
https://www.mye28.com/tech/rods_pages/id16.html
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