Need to sand plastic lenses to bare plastic

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PostPosted: Sat May 14, 2016 6:49 pm
I really need to sand my headlights all the way through some krylon clearcoat and through the OEM UV sealant to the bare plastic so that I can reclear them properly.

I have previously wetsanded them, but it takes a huge amount of time and it's hard for me to see where any patches remain. Is there a faster way to get them prepped, and maybe some kind of light I can use to differentiate between naked plastic and the UV coat?

I'm considering getting an air sander, since I plan to also do various other painting projects and think it would be very nice to have.



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PostPosted: Sat May 14, 2016 10:10 pm
I have no idea how to see if youve sa.ded to plastic or uv but lemme offer another suggestion.

The reason headlights haze is because the old uv coat becomes ineffective and the plastic and coat start yetllowing/hazing. When you sand it, you remove all effected areas and then you throw a new protector on top and smooth it out and your done.

It seems your issue is that you have trouble telling if you have removed all the haze and yellow in an area while you are sanding. This happens(at least in my exp) because the water while wetsanding makes your lights appear to be perfect when there are still imperfections because it fills everything. So what i do is take a dry microfiber cloth and pour in some 90% rubbing alcohol and then i wipe off the lights. I find this gets rid off the water and dries them up very quickly. Then you can look at the light to see if youve missed any spots. You can tell youve got everything when your headlights have a nice even haze from your horizontal sanding(only do horizontal if rattle can coating to help pr3vent runs) and there are no wavy lines which are a sign of r3maining imperf3ctions. I usually go 600 then 1k grit and then rattle clear with rustoleum uv resistant clear for plastics. Then i sqnd with 2k sandpaper and then with rubbing compound. Then i have new lights.

As for a quick way to get through your krylon, i would grab an orbital sander.

Also, you dont need to get all the uv layer off to restore the lights. Just the hazed/yellow.

I know i didnt really answer your actual q so well but i hope my advice helps when you get that krylon off.

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PostPosted: Sun May 15, 2016 12:35 am
Yeah a orbital sander would be the way to go. Or to step up your grits till you can polish.
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PostPosted: Sun May 15, 2016 7:50 pm
Thankyou. Is there a specific one I should order, so that I can more easily acquire different grits of paper? I'd prefer a cheap one until I can save up and get a nicer one. I have a second set of lenses I can practice on, and am really gentle on tools.

EDIT: I just saw your post, rahat123. The old UV coat reacted to the Krylon and crazed underneath it in some spots, so I think I need to take it all off. Thanks for the advice with the alcohol. I was using just plain microfiber to wipe them dry and then trying to look at them.

I've had good luck with Krylon, but am considering giving them a professional clear coat. I have some paint guns and have access to someone who used to paint planes and cars for a living (he paints control panel boxes now, and he does a really nice job).

You guys will probably be hearing from me again, if not about my car, then about my BF's car:
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