My fiberglass bumper has cracks and is white.

This cars value is not much and I don't need it to be perfect. I'm quite happy to just get it back to black with all the cracks and leave it at that.

However was also wanting to know:

a) If I did just paint this black can I just leave it at that or might it cause any problems later?

b) Is there a better easy and cheap diy way of repairing this? Is it different from plastic e.g. Do I need to\can I use a filler etc to fill in gaps as its fiberglass?

pic 1

enter image description here

Also what about those little circle paint chips, do I just apply a blob of black paint over them and that's the end of it?

  • I cannot see the image, but are you sure it's fiberglass? There are very few cars today which use fiberglass for any type of body panel. Are you wondering about flexible, non-metal bumper covers? If so, there is a question about it already on here. So you know, there is a different way to refinish flexible bumpers as they need a flexible paint (or flexible ingredients within the paint). If it cures hard like regular paint does, it will soon crack and flake off of a flexible bumper. I'll see if I can find the duplicate question for you. Commented Apr 16, 2018 at 15:25
  • @Pᴀᴜʟsᴛᴇʀ2 There's an exposed area in the bottom photo, which looks like GRP to me?
    – Nick C
    Commented Apr 16, 2018 at 15:27
  • @NickC It's an aftermarket bumper and I was told its fiberglass but yeah, as you can see from the exposed bits they like it has been constructed from lots of straw/fibers. Commented Apr 16, 2018 at 15:39
  • @JamesWilson GRP and fibreglass are the same thing, the fibres you see are the glass, which is bonded together with resin. The repair kits I mentioned contain mats of glass-fibre and a bottle of resin and hardener
    – Nick C
    Commented Apr 16, 2018 at 18:30
  • I'd agree ... those are fiberglass bumpers :o) Sorry for any confusion. Commented Apr 16, 2018 at 20:16

1 Answer 1


You can buy GRP repair kits, which include the resin, hardener, etc from most automotive supply shops - I wouldn't recommend just leaving it as the cracks will weaken the structure of the area. As @Paulster2 says though, check that it is indeed GRP (Fibreglass is a brand name...) - but it looks like it to me from the exposed area in the bottom photo.

  • what about the little white spots, do I just put a blob of paint there? thanks. Commented Apr 16, 2018 at 15:41
  • I'd spray over the whole area, it'll look neater.
    – Nick C
    Commented Apr 16, 2018 at 18:26
  • not that it matters here but "fiberglass" is not a brand name. "fiberglas" (one s ) is trademarked by owens corning though.
    – agentp
    Commented Apr 17, 2018 at 22:59
  • @agentp - thanks, I was misinformed! GRP is still the correct term though ;)
    – Nick C
    Commented Apr 18, 2018 at 8:42

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