DIY options for headlight refinishing clearcoats?

[4xdog]

I refinished one of the headlights on my 2008 RX350 using the headlight restoration kit from Griot's Garage in September 2018. I was really pleased with the results. The 3200 grit Micro Mesh sanding pad does a fine job of prepping the weathered polycarbonate lenses, and the sunlight-cured UV coating went on perfectly and cured hard in a sunny afternoon.

I have a small spot beginning to weather off the center of the lens after 18 months. Griot's talks about two years life, so I'm probably in the window. Perhaps my coating wet film thickness was too thin in that area.

Buying another Griot's kit is probably my first choice, but it's an expensive item for the small amount of UV coating that's included. There's enough coating to do two lenses with little extra and the spray can doesn't like to be part used and stored (it seems to evaporate from the sealed can and doesn't spray well several months later).

I've tried SEM's UV clearcoat, and normal daylight doesn't seem to be enough to kick off the cure, whereas a sunny day is more than enough for Griot's. I've tried some other clearcoats and they're not as clear or as good at leveling as the Griot's stuff. It really is a good coating...

Any recommendations from the gang would be appreciated.

Here's a before-after comparison on my RX. The 1.5+ year old coating looks almost like when applied but for a spot smaller than a dime that seems to have weathered off.

 

[4xdog]

Griot's in fact appears to have a two year guarantee on their headlight kit, so my failure in 19 months gives me something to talk to them about. Five summer months of that time was with the car covered in a closed garage.

Ran some experiments on a cloudless, bright sunny day today and was able to get the SEM Solaray UV clearcoat spray to cure at least somewhat on a piece of glass. Not tacky (which is what I've had happen in the past). I'll see end of tomorrow how hard the coating seems to be.

The SEM product is supposed to be cured by a high-intensity portable UV light, which is the kind of thing a body shop would have (and I might have had in my lab in my old job). But all I have is our friend Sol.

 

[toplessHO]

any reason not to try a automotive clear like SPI that has real good UV resistance?
those turned out nice.
I m in the middle of doing my Escalade,hope they turn out as good.

 

[astroracer]

I use an automotive BC/CC clear. Dupont Nason was used on the tail lights of my truck nearly twenty years ago and they still look great.

I sanded them down with a soft pad 800 grit before spraying the border to match the truck. The clear paint made them totally clear again.
I have to do the head lights on my Envoy and will use the Nason clear.
Mark

 

[Daves69]

Cerakote has come out with a coating. Guaranteed for as long as you own the car.

https://www.cerakote.com/shop/cerakote-equipment/AH-CHLKIT00/cerakote-headlight-kit

 

[toplessHO]

they make good stuff
I may try a kit

Wondering if the sealer/coating can be bought separately

 

[4xdog]

I use an automotive BC/CC clear. Dupont Nason was used on the tail lights of my truck nearly twenty years ago and they still look great.

I sanded them down with a soft pad 800 grit before spraying the border to match the truck. The clear paint made them totally clear again.
I have to do the head lights on my Envoy and will use the Nason clear.
Mark

Your logic sounds fine, Mark, and worth a try. But note that automotive taillight lenses are made of acrylic (polymethyl methacrylate), a *highly* UV-resistant polymer. Headlights are made of polycarbonate (the basic polymer in Lexan) for its high impact strength. But PC is a lot more sensitive to environmental weathering than PMMA, especially in the presence of moisture, which tends to craze the polymer.

I wouldn't epect 20 years from a Nason clear coat over polycarbonate.

Still, a reasonable approach if it lasts a few years.

 

[4xdog]

Cerakote has come out with a coating. Guaranteed for as long as you own the car.

https://www.cerakote.com/shop/cerakote-equipment/AH-CHLKIT00/cerakote-headlight-kit

Good to see some other options -- thanks for that reference, Daves69. I'll see what I can find about the chemistry used. ("Ceramic" isn't enough for someone who's spent forty-plus years around chemistry and polymer technology...)

It was not encouraging to hear the announcer in their demo video refer to removing "oxidization" multiple times, an awkward way of adding more syllables to "oxidation".

 

[astroracer]

Your logic sounds fine, Mark, and worth a try. But note that automotive taillight lenses are made of acrylic (polymethyl methacrylate), a *highly* UV-resistant polymer. Headlights are made of polycarbonate (the basic polymer in Lexan) for its high impact strength. But PC is a lot more sensitive to environmental weathering than PMMA, especially in the presence of moisture, which tends to craze the polymer.

I wouldn't epect 20 years from a Nason clear coat over polycarbonate.

Still, a reasonable approach if it lasts a few years.

I had an '00 Monte Carlo SS and clear coated the headlights on that the same way I did the truck taillights. I did that in 2011 or 2012 and the headlights still looked great when I sold the car a couple of years ago. I just didn't have a pic of those lights that you could see well. The clear works great on any of the lights, just d/a them down with 800 grit to remove the "oxidization" and hit them with the clear... It will last for a long time.
Mark

 

[SteveH - CO]

Given the number of comments on Griot's site about the inadequate quantity of clear spray, I would contact them - maybe they'll send you a can. I would think Griots would have good product support.

 

[4xdog]

...I would think Griots would have good product support.

Surprisingly, that's not really my experience. I had a slightly-out-of-warranty issue on an unused product a couple of years ago and they took care of me but I sensed reluctance on their part (which I kinda bulled through).

I sent their customer service email a question on a product I'd bought several months ago and never got a FU back.

I sent a note with photo links to the clearcoat coming off my Lexus yesterday and haven't heard back yet. I'll call them on the phone before the week's out if no reply in the meantime.

Some of those comments about the too-small quantity in the can are probably mine -- it's a padiddle liddle bit to work with.

Here's my clearcoat coming off: