Headlight Restoration-new UV sealant idea

[ray6]

When you say fogginess are you talking about being cloudy or from sandpaper scratches? No direct experience with spar/MS method, but I would assume it would fill in any sanding scratches at 3000 unless mixed too thinly.

If it's internal, there's not much you can do about it. I'm not wild about the spar method, but your process seems good. Would stay away from cordless drill and stick with D/A Groit. I'm assuming you're using 3" disks?

I would also eliminate final clean with MS if you're using alcohol wipe as final step. Just wipe off sanding residue then scrub with alcohol.

Also might suggest using a good sanding aid such as Speedokote during all sanding operations. Gives you a finer surface and minimizes possibility of paper balling. Also increases abrasive lifetime.

Would also try to increase spar to ms ratio. The more spar, the thicker the coating and longer lifetime. Will also cover sanding scratches better.

Depending on temperature and humidity, try 70/30 or 80/20 (spar vs. MS). Apply just a small patch and see how it flows. If it's too thick to apply, just wipe it off with MS, add additional MS and try again. After awhile, I've heard it's easy to judge conditions and mix accordingly.

Make sure you are using a quality paper like Mirka, 3M, Norton, etc. Paper quality does matter and will last longer. May be more expensive to buy, but cheaper overall because it will lower sanding efforts and last longer. Sanding aid also helps.
Ray6

[GP49]

It MIGHT be fogginess deep in the plastic itself, or on the inside of the headlight.

Or, has it been humid up your way lately, so that moisture is getting to the sealant as it cures?

[Always Learning]

All of my papers are Norton except the last step 3M trizec. All 3" on the Girot DA.

I've always used just water for a sanding aid. I didn't realize a special aid would help that much. Do you recommend wet sanding all the way up or doing some dry sanding at first?

Is there a way to rule out the humidity factor?

I'll also try thickening the mix as well.

Thanks.
Doug

[GP49]

Could try turning the headlights on high beam for a few minutes to drive off humidity. Also, as Ray said, the alcohol wipe might be the better choice for the final cleaning before coating, as alcohol is miscible with water and could draw out more moisture, if you allow it to dry thoroughly before applying the urethane (another reason to turn the headlights on).

[ray6]

I recommend using sanding aid for all steps.
Eliminates dust.
Lubricates abrasive and keeps headlight cooler.
Makes removed particles float on the surface instead of clogging up abrasive.
Lower evaporation rate than water.
Speedokote is also a foam so it sticks well to the surface.

Downside is that if you're not careful, it will throw slurry on paint that will have to be wiped off when done.

Although Speedokote is great, if you don't have it, add Dawn dishwashing soap to your water. Wipe your disk frequently.

High humidity or moisture on the headlight when applying coating will generally show itself as white streaking.

If humidity/temperature is a constant problem, I would consider going to a 2K water based coating. More expensive than solvent based, but much easier to work with and longer lifetime. Would probably add 75 cents cost per headlight.
ray6

[ray6]

There's been so much talk about using the spar/MS method we were able to get a sample from one of our out of state dealers (can't buy it in California) and run some tests. Was actually surprised how well it did, but still am concerned with it's projected lifetime.
Will follow up with the same test sequance using other coating products.
Left photo
http://www.autogeekonline.net/forum/...1&d=1346259508
This is what the headlight surface looks like before restoration. The UV protective layer has broken down and is no longer cross-linked.
next
http://www.autogeekonline.net/forum/...1&d=1346259508
This is what the surface looks like after sanding with 500 grit.
next
http://www.autogeekonline.net/forum/...1&d=1346259508
Here's 1000 grit.
next
http://www.autogeekonline.net/forum/...1&d=1346259508
Here's 1500 grit, minimum for most solvent based coatings.
Far right
http://www.autogeekonline.net/forum/attachment.php
attachmentid=13354&stc=1&d=1346259508
Here's the surface after 1 coat of spar/MS at 50:50. Notice how it fills in most of the sanding scratches.
ray6

[Always Learning]

I did a pair last night, modifying slightly. Unfortunately I didn't read your post about the speedcoat / dawn, so used water as a lube from 800 up. If neither is available, would Optimum No Rinse / water combination be ok?

400, 600 dry
800, 1500, 3000 wet

Cleaned everything with Odorless Mineral Spirits, had the lights put on for a few minutes. Cleaned again twice with Proponol then sealed. Once again, they looked great till the lights were turned on and then you could see some cloudiness. It didn't seem humid at the time.

Do the rest of you get no noticeable haziness / cloudiness even with the lights on?

Thanks

[jrs1418]

All i gotta say is WOW! Tried this today on one of my headlights for a sample. Last week I resurfaced my headlights as they were starting to oxidize and had some deeper scratches in them. My normal process is 800,1500,2000 wet sand, then polish & UV protect with meguiars, but last week I sealed with this new PTFE/Acrylic sealant I have.

So today I wanted to do one headlight with the 50/50 Mineral spirits and spar urethane. SO i cleaned the headlights with 70% Ipa, sanded with 2000, IPA again, then the 50/50 mixture.

I had to do my light 2 times because i found that the more you try and level out the lines while it's drying, the more lines you get and it doesn't look even. So i cleaned with mineral spirits and then IPA again and went back with the mixture. I soakd the shop towel good and in straight and flowing motion coated the headlights and only went over 2-3 times and left it. The lines evened themselves out and it dried to perfection. This method is noticeably better than polishing. the headlight really looks brand new now. WOW!

[Part-timer]

I did a pair last night, modifying slightly. Unfortunately I didn't read your post about the speedcoat / dawn, so used water as a lube from 800 up. If neither is available, would Optimum No Rinse / water combination be ok?

400, 600 dry
800, 1500, 3000 wet

Cleaned everything with Odorless Mineral Spirits, had the lights put on for a few minutes. Cleaned again twice with Proponol then sealed. Once again, they looked great till the lights were turned on and then you could see some cloudiness. It didn't seem humid at the time.

Do the rest of you get no noticeable haziness / cloudiness even with the lights on?

Thanks

You may have a problem simply with the inside of the lens. If the lens is not sealed properly from the factory dirt and moisture can get in (also if the bulbs seal is no good), or if there are cracks somewhere.....you can get cloudiness/fog on the inside. There is no way to fix that...unless you have a way to seperate the two halves....clean the inside...and reassemble with a sealer so that it is air-tight.
Also, some lenses simply have damage to the polycarbonite itself and this will show up when you turn the headlights on. Nothing that I know of can fix this condition.

[ray6]

I would suggest not using 70% IPA for your final clean. 70% contains 30% water. Water is your enemy. You're better off just using the MS as a final clean.

100% alcohol will clean slightly better than MS and will dry faster, but MS is better than 70% IPA since moisture can give you real problems.
ray6