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Restoring plastic headlamps

8K views 22 replies 6 participants last post by  Marcwithac 
#1 ·
Hi all,

Just started sorting the headlights on my puma. Have wet sanded them back, finishing with 2500 grit.
In order to polish them I'm having to use a backing plate on a corded drill and a combo of white/yellow rupes pads and Megs 105/205.
Problem is that although the sand marks are coming out I seem to have swirl marks that I can't remove. Am I causing them??

Have now also done several passes with my DA using an orange hex logic with some 205. It's removed almost all the marks now but the swirls still remain. Am stumped!
 
#4 ·
If you're absolutely sure you took all the pitting out, then you just need to step up to a harder pad with the same polish, or a more aggressive polish with the same pad. I know 205 is usually enough, but I use it on rotary.

Polish a small area again, and use your swirl spotter to see if it's any better, if it's not, you may have to resand again, or the swirls may be on the inside!

I've had this before when I didn't sand down the last step properly (2500) - I probably spent 40 mins on one side, and 30 mins on the other, and the 30 min side still shows swirls no matter how much I polish it. It was my first car, so didn't make that mistake again.

Keep at it - you're nearly there!

If you're going to coat them with something afterwards (Nanolex Si3D Headlight, or Sonax Headlight), you'll probably get some slight filling to your swirls as well.
 
#5 ·
Thanks Tosh. Have also just tried another small section with a wet sand of 2500 with very light pressure, in a cross hatch, then a couple of passes with PlastX on an orange hex pad. It's removed the sand marks but the swirls remain...
Either I've not sanded enough (which I struggle to believe), I've induced more swirls or, as you say they are on the inside. Am honestly stumped.

As far as sealing goes, assuming I get that far, was hoping to use some Gtechniq C4- is that suitable?

Thanks for your help.
 
#6 · (Edited)
Personally, if you have C4 already it will work (it's the same as C1 and GTechniq have confirmed that's ok).

Don't use Si3D, as that doesn't work well with polished headlights; the headlight version is ok.

If you're going to buy something specifically, Sonax Profiline headlight is good (50ml aerosol), meguiars headlight g17710 is about 12 quid a bottle (only lasts 1-2 months though), or you can get a sachet of stuff for a tenner (lots of them out there, I used Twenty20 Crystalite)

You get these sachets in 3M and AutoGlym kits for UV protection.

Saying that, I did a 10yr old 1 Series, didn't seal it and still hasn't yellowed after 2 years.

I haven't bought the Si 3D headlight yet, but I will do at some point to complete my Nanolex collection.



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#10 ·
Am I expecting too much to be able to remove theses swirls before refining?
Could I be causing them with the wrong pad/compound choices? It's taken a bloody long time to get to where I am now- these are only plastic! I'd imagined it would be a relatively quick process, compared to a rick hard paint, for example.
 
#11 ·
All I can say is if you've sanded at 800, 1200, 2000, 2500 then there aren't any swirls left!

Thinking about it; got to be your pad/polish combination. I used to use PlastX on a white pad; when I ran out of that, Menz IP on an orange and white pad.

I was left with sparkly lights which were stone chips because I didn't go deep enough with the sanding. But no swirls. Again I was on a rotary.

Bet you'll never do these lights ever again!


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#12 ·
That's what I'm thinking- having wet sanded as you've said, how can there be swirls? Admittedly I may have caused then by initially using a power drill/backing plate/pad combo bit how have I not polished then out yet?? I've literally spent 30-40 mins every night this week and still they remain!!
I'm either dealing with the worlds toughest plastic (granted they are 16 years old) or I'm causing them as I go, with a DA.
Am thinking that I'll wet sand again at 2500 then try PlastX on a soft pad, if that doesn't sort it then I quit!!
 
#14 ·
Fair point. I didn't use a sanding disc, did it by hand and worked as clean as possible. I think my mistake was to start the compounding with a pad fitted to a corded power drill, as I've only got a DAS6 pro plus that can't run any smaller than a 5" pad. I figured this would be too big on my headlamp, bit have had to resort to using it anyway, although I have discovered that you can put a 4" pad on a 5" plate- you just need to be incredibly careful!!
 
#17 ·
Right, so I started on the other headlight, to try and work out where ive gone wrong.
Wet sanded by hand from 800-2500. Have got rid of all the sanding marks without too much problem and it looks fantastic- until you introduce some light. Bloody swirls are evident again!!?
I've tried every combination of pad/compound/speed I can think of and nothing is working. Honestly at a complete loss and thoroughly fed up with it.
Anyone got any idea what the hell I'm doing wrong? It seems I'm causing them but I've no idea why...
 
#18 ·
I would try and hand polish at this stage, don't use the machine.

Alternatively, either borrow a rotary or drill mounted backing pad and try again with a new 4" pad and the lightest polish you have. The throw on your polisher may be the culprit.


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#19 ·
Thanks Tosh. I have got a backing plate for a drill, that's how I started polishing the first lamp, and what I thought was the culprit for the dreaded swirls.
Lightest compound I've got is M205, either that or PlastX, which I'm told is fairly light.
Had thought the plastic would be hard, but am now thinking maybe it's very soft. Watched an Ammo vid on YouTube about polishing with just water for very soft surfaces- might give that a go too. Thanks for your help and I'll let you know...
 
#20 ·
Me again! Still fighting!! Was making zero progress so admitted defeat and went to my local professional. They suggest a very light compound and a soft pad should be sufficient, just experiment with amount of time spent on each pass. Bought some Rupes white compound and used a rupes white pad..
Well, I've done that and, guess what- zero difference!!?
Genuinely at a loss now ss to what I'm
Doing wrong. May have to admit defeat and just seal the bloody things.
 
#21 ·
Can i suggest again that you give the AutoGlym kit a go. It has all stages of wet and dry paper and a final cutting compound and pad to use which when i used it finished off my lights beautifully and left no swirls.

If you're anywhere near Rugby you're welcome to borrow my kit to see if it works for you.
 
#22 ·
Can you post up some pics so we can see the difference you've made already and the swirls you're talking about?
I did mine recently using a similar combination as you. Mine were very heavily damaged and I used 800, 1200, 2000 by hand, 3000 by da, then HD Heavy Cut on a mf pad, Menz PF2500 on a hard orange Scholl pad, Rupes Keramik on a blue medium Scholl pad then finally sealed with Werkstat Prime on a AF soft yellow pad. Potentially people may say that's overkill for the amount of steps but I'm more than happy with the result and have an absolutely flawless finish even under the sun gun or metal halide light. DA was a DAS6 Pro with the 3in backing plate, rather than a drill like you. Took around 5 hours in total to do both headlights (and I split them in half rather than doing the whole thing in one go).

Where are you based? Happy to lend you my DA with smaller backing plate if you're anywhere close to Maidstone mate.
 
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