View Full Version : filling in headlight washer holes..

04-28-2008, 05:27 PM
I wanna try to fill in the headlight washer holes on my s4 front before I get it painted, what's the best way to do this? I've got a few ideas, but I know some of you guys are real good with body work and what materials to use.. So, whats the right way to do it? Thanks

04-28-2008, 06:43 PM
You can glue a piece of plastic on the back and then fill it.

04-28-2008, 07:30 PM
You can glue a piece of plastic on the back and then fill it.

fiber glassing the back would be alot better. Its really easy

04-28-2008, 07:32 PM
I have read that fiberglass and the plastic do not go so well together? Also, wouldn't that be prone to cracking? fiberglass is pretty stiff.

04-28-2008, 08:17 PM
I know nothing about body work on cars, but I know from working with fiberglass for boats, that polyester resin is more brittle and stronger (what u get for cars normally I believe) where as Epoxy resin is more flexible but it is considerably more expensive and much more difficult to mix right.

04-28-2008, 09:14 PM
I have read that fiberglass and the plastic do not go so well together? Also, wouldn't that be prone to cracking? fiberglass is pretty stiff.

Nope, fiberglass can be used to repair many things. Rocker panels, Hoods, Shaving door handles, lawnmower decks, etc.
NTM it's really easy. Just don't put too much MEKP(liquid hardener) in it. Shit can hit the fan really quickly if you over do it.

04-28-2008, 09:37 PM
Here is what I did.

I cut out some lexan that was slightly longer then the opening. Put a screw thru the center so I had something to hold it up while the epoxy set. Once it was set I just filled in the rest of the area with a fiber glass product like Kitty Hair. Used that to fill in the rest of the opening and then sanded it flat with the surface of the bumper skin.





04-28-2008, 11:15 PM
while all the responses above might work, none is really correct

I'd use a donor bumper to source some TPO material, use a plastic welder to take the patch in from the top, then I'd reinforce the patch on the bottom with a TPO adhesive, then I'd fully plastic weld the top , and sand/ paint

fiberglass in the conventional form of resin and hardener will not adhere properly to you bumper and will fail at some point

04-29-2008, 11:07 AM
yea, that's probably true, But I'll stick with the homebrew techniques.

04-29-2008, 01:10 PM
Mike, tripping for your car big time, looks fantastic! [up]

Talk to me about a CF bonnet. Problem is, I'm in the UK.

I still want one though. [cool]

04-29-2008, 01:19 PM
Plastic welding is messy and a pain in the butt. Fiberglass, or Duraglass, or Kitty Hair is the way to go here. Don't worry about flexibility since this portion of the bumper is not flexible due to it's proximity to curves and the bumper beam.

There are a couple ways to do it depending on what you have on hand. You can superglue or epoxy a piece of plastic, mesh, or screen behind the opening and then use the Duraglass or Kitty Hair to fill it in. Wait for it to set and then sand it smooth. Be sure it is fully cured before painting otherwise the painter's curing oven may shrink it and put a hairline crack in the paint. Be sure to put a layer of glass on the backside too to make it all stronger.

Even though I knew better, I used body filler and it cracked in the paint curing oven. It isn't bad and could easily be touched up so that it was invisible.


You can't see the hairline crack from more than a foot or two away. You can, however, see where a mountain bike frame fell from the garage rafters and nailed the bumper...

It has held up through some pretty crazy weather. This was after getting run off the road, biffing a huge snowdrift, and spinning across two lanes before pulling a nice 20mph Rockford (J-turn) and casually carrying on.