Headlight Refurbishment

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  • November 11, 2013 at 1:14 am #45367

    I did a quickish restoration on a friends Nissan Micra mk3 headlights today, he had failed MOT test for them being clouded. They were pretty bad and I hit them first with a P220 thin foam sanding pad (wet). Then went on to paper P400, P600 then P1200 (all wet). Finished off with G3 on a rotary.

    I got the light output much improved and with a quick passing glance they looked a lot clearer, but up close there were still lots of sanding marks, possibly from the P220 pad. So I’m just wondering how you guys find headlights to work on – do you spend hours on them and are they harder to sand up than paint?

    November 11, 2013 at 1:23 am #45368

    They aren’t hard to remove scratches from.

    I think the problem is you jumped too far between grits. 220 may be a little coarse to start with, but workable if necessary. You probably should have gone: 220-320-400-500-600-800-1000-1200-1500.

    Otherwise you could have stopped in the 600-800 range and clear coated them.

    November 11, 2013 at 2:52 am #45369

    ive found they look a lil clearer if ya really work em hard with 1000 b4 ya clear em i always check there clarity with pre cleano b4 i clear em if they still look a lil milky i keep buzzing em with the 1000 on the interface pad with my da dry 800 for some reason doesnt seem ta be enuff on the plastic lenses for some reason ive found :blush:
    also try an get all the factory coating off first with 320 or 400 then step out with the finer grits hope this helps i also polish first b4 i start sanding ta get all the grime off some lights are easier ta do than others dont be afraid ta sand the living shit outta em but remember if ya dont step all the grits all the way out it will show when ya clear em

    November 11, 2013 at 11:00 am #45370

    Hi mate, hand sanded or DA?

    I recently did a set of Passat ones as parts of a How-to for an Audi forum. They were sanded with DA using my regular steps of 180 – 240 – 500 – 1000 – 2000, before polishing. If I were hand sanding I’d work through more intermediate grades as Ben suggests, plus as you switch to each new grade sand at a slightly different angle so you can see for sure that all the scratches from the previous grade have been removed.

    [url=http://audisrs.com/about49266.html]The full article is here[/url], scroll down to see comments about hand sanding.

    And this is a before and after. You can see how bad they were, an instant MOT fail!

    [img]http://i321.photobucket.com/albums/nn385/Duluxdude/Paint%20Correction/Passat%20B5%20Headlamps/2013-10-12112727-1Large_zpsd1cbfe33.jpg[/img]

    November 12, 2013 at 3:32 pm #45372

    Thanks for the replies. Andy, the ones I did were at least as bad as that. I did all the sanding by hand and tried to sand up and down then left and right – but on each grit rather than alternating (is that bad?). Reading what you said in that thread, I started too coarse for hand sanding. I didn’t want to DA them as they have a bulge in the top like a frogs head, and I wanted to wet sand them. My DA sander is electric.

    I guess the issue now is how to remove the P220 scratches? I did work quite hard with P400, is skipping one grade really going to make that much difference? I do have a mini (2 inch) air DA sander – if I could get a foam backed velcro pad for this maybe I could tackle the bulge?

    edit: something like this but with the screw thread to suit my tool [url=http://www.powertoolsdirect.com/flexipads-spindle-pad-50mm-conical-soft-face-velcro]foam backing pad[/url]

    November 12, 2013 at 6:27 pm #45384

    I do a ton of headlamps. First, stay away from any solvent stronger than your wax remover. If the lamps have any tiny cracks “fissures”, solvent will soak into them and make them look worse. I use PreCleno or RM 900 to clean them.

    Depending on how bad they are, I usually start with 400/wet using a soft block. I have had to use 240 on some really bad ones. Then 600, 800 and sometimes 1500 if I have nothing else to do but 800 usually looks pretty good. 1500 really makes them “pop”. Then I clear coat them. If I leave the lamps in the car, I can do a set in about 40 minutes. I charge around $100 for a set.

    It’s almost always an “add on”, the car was in the shop for another reason for another repair or it is to get a car through Maryland State Inspection.

    November 12, 2013 at 8:24 pm #45387

    I know the type of headlamp you mean. Rather than buy a backing plate just for the one job I’d probably hand sand around that raised area but machine as much of the rest as possible.

    You could still do it by hand though, it’ll just take a little longer. I’d try going back to the 400 or 600 for a bit and just check really closely that the deep scratches have gone before moving on. Clearly this is where a guide coat comes in handy, but I’ve never tried using one on a lamp.

    November 12, 2013 at 11:39 pm #45388

    I said I’d redo them after winter as I wanted to clear over them. What would your recommendation be regarding using my electric 125mm DA, or my mini 50mm air DA, or hand? I’m kind of leaning towards the mini DA as I can get around the bulge and generally it’s easier to control? I’m working with the lights on the car. I never thought that a machined grit would work differently to the same grit by hand.

    One comment, I know the US grits are different to European P rated grits so it can be confusing.

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