Chemical reactions to the plastic lens.

 

The cost of a decent clear coat is prohibitive.You might as well buy a new set of headlights.I am all for using a good clearcoat but my point is it is not necessary if easy once a month maintenance is done by spraying a good UV protectant.Like I stated even if you forget or neglect them it takes a few minutes to buff them back out provided you don't let them get really bad.I have kept my headlights clear for many years doing this.I just finished removing a failing clearcoat on a friends car headlights and it was a pita.He was broke so I donated my time but if I had to do it again I would have bought him new headlights....

 

There’s that. Polycarbonate is notoriously sensitive to rapid attack by many chemicals. A urethane would not likely attack it once cured, but when it first goes on wet…

I wonder what’s on a brand new headlight. Doubt if it’s bare polycarbonate.

 

Yes, the manufacturers put a PU or other type clearcoat on headlamp lenses to protect the polycarbonate from UV and chemicals, etc.

is reasonable enough to not be cost prohibitive. I think it's pretty much the same as the product they recommended in the restoration video just made by somebody else.

It's basically one use only product so it only makes sense to have a bunch of headlights all ready to be sprayed so you can get as many as you can clear coated and restored with the one can. I would do my HHR's and my 4Runner's headlights with it and maybe a friend or two's as well if they could get theirs sanded and ready to coat at the same time.

 

I seen in post #25 that you used "UV 2X". Can you tell us what this was exactly?
I am going to wet sand and spray mine and did not want to use what you did if it went foggy.

Thanks

 

This was the product , I used it in October, so possibly not within the temperature range the instructions suggest