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The headlight lenses on my vehicle (a 2001 Ford F-150) are cloudy, and presumably as a result, the headlights are not terribly effective. (I could post a photo if you want.)

I bought a polishing kit (Mother NuLens) and used it as directed. The cloudiness improved slightly but is still pretty bad.

From other questions on this site, the next step appears to be attacking the lenses with various grades of sandpaper and finishing with a final polish. Given my general level of automotive incompetence, I'm guessing this will take me at least a couple of hours (including the return trip to the store when I inevitably discover I've bought the wrong kind of sandpaper, or not enough). The materials will also cost something, and I don't discount the possibility that I'll massively screw up and irreparably scratch or crack the lenses, damage the paint, or perhaps just burn the truck down to the chassis.

So before I get started, I'm hoping to get a sense of what kind of results I can expect for my trouble. If I do things properly (far from a safe assumption), should I end up with glistening, showroom-new headlight lenses, and finally be able to start blinding drivers in the opposing lane? Or is the best case a marginal improvement in clarity and brightness?

Cause unless I can really expect the polishing to make a pretty significant difference, I'd rather save myself the carpal tunnel and just get a new set of lenses (even if that means replacing the whole headlight assembly), possibly from a junkyard.

Something like before-and-after pictures would be great, provided they come from a real person and not a polishing-kit vendor.

(This is somewhat related to New headlight lenses? but a bit different.)

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3 Answers 3

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That process you're describing is VERY familiar to me - I do that for people from time to time. The difference is REALLY SIGNIFICANT... and at most it should take you five minutes of actual work per headlight - it's really pretty minimal, with diminishing returns VERY quickly.

ALWAYS WET-SAND. Do NOT dry-sand. Start with nothing less than #600 sandpaper, stop at no less than #2000. You can step 600-1000-1500-2000. Let the lenses dry. If they're not pretty spectacular yet, give them a dose of automotive "swirl remover" for good measure. Finish up with good silicone-free, 100% carnauba, paste wax (Butcher's or Johnson's or certain types of Turtle). Let THAT set up, buff off. Looks wet. :)

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I just went through a process much like this. My last step was a sort of clearcoat spray to give the lenses some UV protection (rather than wax). All in all, headlights that are 150K miles old suddenly looked brand new. –  Bob Cross Aug 18 at 0:35
    
Thanks very much. By "wet-sand" do you mean to use water or some other liquid? –  Nate Eldredge Aug 18 at 0:37
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Yes, the UV protection like @BobCross is talking about will last much longer than a wax will, though both protect from UV light. Do not overlook this final step of coating your headlight as it will fog up again. To wet sand, use wet/dry sand paper (usually a black/grey sheet) and water. As you sand with it, the water will become milky. –  Paulster2 Aug 18 at 0:39
    
Thanks again for the answer - I tried it and it worked quite well. I added another answer with the details. –  Nate Eldredge Sep 8 at 3:48

I followed TDHofstetter's advice (partly) and I can now report that it is indeed quite effective. I wet-sanded with 600, 1200 and 2000 grit sandpaper (my local hardware store had nothing in between or finer). That removed the yellow discoloration and left the lenses smooth to the touch, but still a little cloudy. I then applied the Mother NuLens polish, using their sponge tool on an electric drill, and then buffed with a microfiber towel. That left them considerably clearer. I didn't try any additional wax or finish.

I wouldn't go so far as to say they are "good as new", but the light output is much improved. They have gone from "marginal for night driving" to "perfectly acceptable", by my personal standards.

I took it rather slow and tentative, since I have little automotive experience, but I was still done in under an hour, including setup, taping around the lenses, cleanup, etc. The sandpaper cost $15 and I have lots of it left over.

The Mother polish claims to provide UV protection. We shall see. However, even if this has to be redone once in a while, it's a simple enough job that I think it still makes more sense for me than replacing the lenses, especially on an older vehicle like this one.

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The most realistic answer to this increasingly common fogging is to fit new headlamps, or lenses if they are available seperately for your vehicle. Problems can and do arise with the headlamps beam pattern and glare. It is just unrealistic to expect a polished up lens made from modern plastic to afford the same performance as a new one. In the UK 'fogged' vehicle headlamps end up in the bin if they do not pass their annual inspection. The cost of replacement can be reduced by a great amount by after-market replacements.

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Are you kidding me? You'd charge customers upwards of $500 (or more) to replace head lamps when the wet-sand method is COMPLETELY viable? It only takes 15 minutes worth of work (maximum) per side to get these results. Last time I checked, charges on 1/2 hour labor is much cheaper than replacement. Sounds like how mechanics treat unknowing women when they want to take advantage of the situation, or the shop is just plain lazy. –  Paulster2 Aug 18 at 22:25
    
After market headlamps for, say, a Mercedes would be around £65 each, fitting 1/2 hr each side at £90 ph, + 20% tax. Converted to USD, $500 sounds about right. In the UK to pass its annual test an headlamp must give a defined beam pattern. Differant companies have tried all sorts of remedies with very poor results. (There are just as many unknowing men in the world as women and it would be suicide for a shop to have a rip off reputation.) –  Allan Osborne Aug 19 at 21:05
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Thanks for your answer. I decided to take the polishing route after all, and as I posted in my answer, it was cheap and relatively easy to do myself, and the results seem pretty good to me. (Around here there is no official inspection requirement.) For this truck, it appears aftermarket headlight assemblies can be had for US$70 the pair, but installation cost could be significant. Given the age of the vehicle the repair seemed more appropriate than replacement, even if the results are not quite as good. –  Nate Eldredge Sep 8 at 3:58

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