How do you guys remove rock chips?
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I got a new (to me)2002 530i, the front bumper has lots of rock chips.
What is the best and easiest way to remove rock chips? Would it help to use use SEM bumper stripper? :blush:
So far I’m thinking:
> 400 grit and lots of sanding
> Adhesion promoter over bare plastic
> 2K primer (is it OK to spray 2K primer over 400 grit scratches?)
> Sand smooth using 800 grit
> BC & CC.Thanks.
I would P180-P220 them out. Prime, sand with P400 d/a or P800 wet and paint.
Make sure to use adpro on bare plastic.
After sanding with P180 or P220 if you want to get the hairness out of the plastic before priming you can wetsand it with some P400 wet.
just did one today on a vw. totally agree with ryan. i did it the exact same way.
Thanks for reply Ryan.
So:
220 grit to remove rock chips
400 wet-sanding bare plastic to remove the hairness
R-M adhesion promoter
2K primer, 800 grit, BC and CC…Is it ok to spray 2k primer over P400 grit? Is that enough for 2K to “bite” into?
Yes the P400 wet should be enough tooth for the primer to bite into. P400 wet is a little rougher than P400 d/a. The wet sanding just knocks out the hairiness you can get when you prime.
You don’t have to get super carried away with the wet sanding, just enough to knock off the top. You can even skip this step, it will just make the primer rougher and may need an extra coat. Not all plastics get hairy either. Usually the PP, PO, TPO, EPMD type plastics.
I do a bumper on youtube….
It might help…its not very technical but shows me working on it…
thats a GREAT vid serge :cheers i really enjoyed it
Thanks Ryan.
Not sure what material the bumper is, but bumper guard trims are ABS+PC.
Thanks again for the reply! I’ll sand with 400 anyway to leave a smoother surface for adhesion promoter and primer. The less coat build up the better!
Thanks again. :cheers
Serge: Great video! It actually motivated me to start the bumper already! (Especially spraying BC & CC part! My favorite part :pcorn: ).
I’ve been telling myself to do it next year, now I’m gonna get to it next week! :cheersThanks…We are still working on the website which we hope will be informative.
The idea is to educate the customers on the steps that are required to repair their cars. It helps understand why its so expensive sometimes. Its not just scratch and shoot…there is a method to this madness… :woohoo:
Websites are alot of work…so are videos…man, you can sink so much time into them…but I enjoy it alot…
Very similar to Ryan’s method, but I’ll P180 the chips out, then finish with P320 to remove the fur. Yes you can go a little finer, but I find a decent 2K primer will cover it 🙂
If its real bad,,,I would replace the bumper with a aftermarket one. Sometimes its faster, cheaper, and a lot less trouble………………..
Hi ODG! :cheers
Its not that bad, but IMO it can be sanded and refinished.
I don’t really want an aftermarket bumper on a BMW. Most of them have crappy fitment. :huntI know of a few companies that sell PP M5 bumpers with decent quality and fitment, but they are in US and I like the face-lifted non-M bumper better (for 5-series).
there actually is a compy here that sells the aftermarket m5 cover complete with fog lights and bumper trim for 280 shiped.
honestly, a aftermarket cover wouldn’t be all that bad on a 5 series, and most likely a faster to paint a new one then dealing with rock chip repair.
I have such a bad taste in my mouth left by bad fitting aftermarket parts – plastic or steel parts. Drives me nuts. Personally I would rather fix the stock than buy new.
I do lots of fiberglass and plastic work as it is, so a little plastic repair on a few holes or cracks in a mangled stock bumper isn’t that bad to me – compared to a few hundred for a new part that probably won’t fit. if you can get a stock bumper from the manufacturer that’s a different story, but I’m sure the bumper cover on a BMW is $1000 or something insane.
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