How to polish headlights so it lasts (re-adding UV protection)

[deejaaa]

used 3M on mine once. looked good for 1 month. replaced just the lens with glass/Lamin-X. have looked like new now for a year.

[Daox]

I'd try to use multiple coats of sealer if I were you worthrj. Mine is still holding up okay with a single coat, but another coat certainly would have helped I think.

[Baltothewolf]

At the shop I sand headlights with 800, 1000 then 1200, ad my co-worker sprays them with euro clear (300$ a gallon) . He has a couple cars that are going on 2 years that still look brand new.

[Daox]

Here is one more technique. He uses rustoleum clear coat that is UV resistant as a top coat. He claims its permanent... yeah right. But, still probably better than most other options.

https://www.youtube.com/watch?v=UEJbKLZ7RmM

[orange4boy]

I hate to be the bringer of bad news but varnish and most polyurethanes have notoriously poor UV protection. They are meant to go on thick and with many coats and they all yellow with age even if they have some UV protection.

The automotive clear coat solution is probably the best followed by automotive clear spray cans and then rustoleum spray can clear. Just don't use clear lacquer unless it's automotive acrylic lacquer. Lacquer meant for wood will attack the plastic.

These days you can get very good quality automotive spray can clears.

BTW, you don't need an expensive kit to do this job, just a fine polish, a cloth and elbow grease. Paint polish works as well, paint is basically plastic anyway, although, if you want to spray it after make sure you use a paint ready polish without wax or you will get fish eyes. It's a good idea to clean the lens with mild solvent before spraying in any event. A mix of 25% water to 75% rubbing alcohol (Isopropyl) can be used for plastic.

[oil pan 4]

I just replaced them on my wifes Hyundai.
$120 ($100 after I redeemed a $20 ebay coupon they randomly gave me) for both head light assemblies. 3 bolts hold each one in, had them changed in about 20 minutes.
I tried buffing them and coating them but the plastic was clouded all the way through, not just the top layer.

[Grant-53]

Any automotive acrylic clear used in a base coat/ clear coat system should be UV resistant.

[bikeprof]

Here is an EASY temporary "fix":
Toothpaste, ANYTHING that has some grit in it to clean teeth tartar does good, BEST one I've found is ARM & HAMMER.

Pad on cream, rub like MANY times and repeat a couple more...
Rinse; "voila', it's done!

[Xist]

I buffed mine and was amazed, but now I do not even remember which headlight it was, because it yellowed as bad as before.

You need to protect it, which I neglected to do, and I doubt that toothpaste does that.

[Daox]

Its been a year and 1 month now. I'll have to get another picture or two, but the Metro's driver side headlight is still holding up fairly well. The passenger one needs to be redone. Its not horrible, but its not good. I can tell a difference in light output when I pull up to my garage door. I'll see if I can get a picture of that for you too.