Cleaning headlights

[Snipe Hunter]

If you have a spray gun:

First, if any of the damage to the headlamp is on the inside of the lens... you're toast. But you'll never now till you fix the outside. The inside damage isn't too common but I do see it. Mostly on the Mitsubishi and Chrysler products.

OEM headlamp lenses are coated with a clear UV resistant topcoat. When the topcoat fails, the sun eats away the poly-carbonate and it oxidize. So to really fix them, you need to sand off the oxidization, sand out the damage to the poly and apply a new topcoat.

First, I clean the lens with a solution of ammonia and water. I use the cheap yellow ammonia. Never use solvents on poly lenses or you'll never get it right. It will soften the lens making it near impossible to sand and it will push the stained yellow mess from sanding into any fissures and you can't get it out.

Then I tape off around the lens to insure I don't scratch the paint with my sand paper. Depending on how deep the damage is dictates which grit I start with. WET-SAND every step. If 600 grit doesn't cut it, I'll go to 400 and if it still doesn't cut it, I'll go to 240 grit. It's rare that I have to use 240.Sometimes I can get away with starting with 600 grit if the lens isn't eaten away too badly.  ALWAYS use a sanding block, fingertips aren't flat and you'll only have a few small points of sand paper contact. I use the black side of the Motor-Guard soft block for all my wet-sanding.

Not only are you sanding off the failed topcoat, you are sanding down to the bottom of any pitting in the poly. So I work my way down from the coarse grits to the finer grits. 400-600-800- and then finish off with 1500. I've stopped at 800 before and it will do in a pinch but still doesn't look like a new lens when done. 1000 or 1200 would probably do just fine but I don't stock it. 

Then I clean again with the ammonia solution and wash it off with water and a tiny little bit of dish soap, maybe 2 drops of dish soap in a quart of water. Then I rinse it off with clean water.

Once dry, I mask off around the lenses and shoot a 2 part automotive clear-coat over the lens. Looks like new and will last a lifetime. It's a better topcoat than what's applied by the manufacturer.

[R Clark]

I've been following this thread with interest so obviously my headlights could use some help. My question is how much of an improvement does it make to how bright the lights shine? Is it a major improvement, or should I just get some "off road" replacement bulbs to compete with oncoming blue tinted ones that are blinding and somewhat aggravating when in all three mirrors?

Like AgGEM said, it will be a huge improvement.

Replacing bulbs without cleaning the lenses will do nothing for you.

You can replace the headlight assemblies if you want absolutely clear lenses, but that's expensive and a surprising amount of work to get installed and adjusted correctly.

[R Clark]

...

Once dry, I mask off around the lenses and shoot a 2 part automotive clear-coat over the lens. ...

Snipe:  I presume that the topcoat you apply is a professional-grade product.  Is that true, and if so, is there a rattle-can product that is a reasonable substitute?  I don't have spray equipment...

[Snipe Hunter]

BTW, there are aerosol 2k clear coats on the market. It will save you a good bit of cash. I can send you a care package of the sand paper. Might even have an old sanding block around. Shoot me a PM if you need help with this. I've done hundreds of these things.

Rattle can 2k clear-coat

Another source for the sanding block

PAck of assorted wet/dry sand paper

[Snipe Hunter]

Wear a respirator (or hold your breath like I do ) when shooting this clear.

This 2 part clear is mixed inside the can so once activated it won't last long before it hardens. So do all your prep work and shoot this clear on a practice piece.

You should only need one coat. The key is to lay down a wet coat without running it. Don't try to dust on light coats, it will look like crap. One wet coat.

If you do run it, wait a couple days and sand out the runs with the block and 1500 grit and buff it. Or just live with the run, it will still lok better than it does now.

[Snipe Hunter]

I did one recently for a friend and he took some picks. Just texted him and he's sending them to me and I'll post them.

[Snipe Hunter]

Here you go

Hold your sand paper like this. If you cut it right, you'll get 8 pieces of sand paper from a 9x11 sheet.

[Snipe Hunter]

Not exactly step by step but these pics are sanded, masked and clear coated.

[R Clark]

Thanks, Snipe.

I've got plenty of wet/dry abrasives; thanks for the offer.  The source on the rattle can of 2K is a great help. 

Of course, I don't have a need for this right now.  My truck is still new enough and it's good.  Is there enough benefit to doing this on a newer vehicle before the headlights go funky?

The wife's SUV has brand new headlights, along with the rest of it as we had to replace the totaled Highlander. 

[MstrCarpenter]

From AAA

Research revealed that deteriorated headlights, when used on low beam, provided just 22 percent of the amount of light a new headlight does when operating at full capacity. AAA also examined the effects that replacing or restoring a headlight can have on improving the amount of light produced. Replacing  headlights with original equipment manufacturer parts is the most effective method to restore light output back to 100 percent.

Aftermarket parts also performed well, restoring light output between 83 and 90 percent, however these did fail to meet certain requirements for light intensity and were found to be more likely to produce glare for oncoming traffic. Restoring headlights, while the most cost effective option, offered less of an improvement in light output than replacement. Professional and DIY restoration returned light output back to approximately 70 percent. Both restoration methods, however, produced more glare than is acceptable according DOT criteria.

Thanks for this enlightening information.
I know new cars have brighter lights, that my lights were getting dimmer, and my eyesight is getting worse. This info. helps take some of the blame off my eyesight. I'll restore the lenses today, as I have the supplies in the shop. I think I'll get an upgrade to the OEM 9007 halogen bulbs too. Any suggestions for an '07 E350?