Sprayed Universal Clear on headlights and it's starting to peel...

[VB]

Hi guys,

I sprayed some Universal Clear on some headlights about 2 years ago and it's starting to peel on the edges. I would like to understand what I did wrong. I took my time to prep the headlights well and made sure they were nice and clean before clearing them.

I had used a red scotchbrite pad to sand them.

I didn't use an adhesion promoter. Is it safe to assume this was my mistake?

Thanks.

 

[Bob Hollinshead]

Where it's peeling can you still see the scotchbrite scratches? Post up a picture. The only failures I've had was on a third brake light, I think it was polycarbonate of some type, couldn't get anything to stick to it.

 

[rebeldart]

Where it's peeling can you still see the scotchbrite scratches? Post up a picture. The only failures I've had was on a third brake light, I think it was polycarbonate of some type, couldn't get anything to stick to it.

I'm out of touch on this topic - didn't know it was done (clearcoating headlights) I'll do a search for more info ........... longevity ?

 

[VB]

Where it's peeling can you still see the scotchbrite scratches? Post up a picture. The only failures I've had was on a third brake light, I think it was polycarbonate of some type, couldn't get anything to stick to it.

It's not my car so I can't get a pic of them right now unfortunately. I looked at it closely and it feels very smooth in the area where the clear coat peeled off. It does seem like the scratches are showing from the sanding. The headlights are from a 2005 Honda Civic, not sure if that helps or not.

I'm out of touch on this topic - didn't know it was done (clearcoating headlights) I'll do a search for more info ........... longevity ?

I've heard of it being done before instead of wetsanding and polishing the lights when they start to fade or yellow. Aside from the peeling the rest of the lights are still really clear.

 

[Bob Hollinshead]

I've never had a problem with adhesion on headlights, if you can see the scuff marks then improper scuffing wasn't the problem, could be a cleaning problem? I know I avoid using solvent wax and grease remover and only use the waterborne cleaner on plastics.

 

[crashtech]

Some headlights have an optical coating over them that is solvent resistant and can affect appearance and adhesion. We've been sanding lenses pretty far down even around the edges starting with 400 wet and working up through 1200 to get to "virgin" plastic. Sometimes you can detect the presence of an optical coating by the fact that once cleared, it will be slightly less transparent compared to areas where the coating was removed or had degraded to the point where it was gone.

 

[Panelwagon62]

I always sand that coating off, you can see it feather away as you sand. Never had adhesion proems that way.

 

[VB]

I've never had a problem with adhesion on headlights, if you can see the scuff marks then improper scuffing wasn't the problem, could be a cleaning problem? I know I avoid using solvent wax and grease remover and only use the waterborne cleaner on plastics.

I had used the SPI Waterborne Wax & Grease remover to clean them.

Some headlights have an optical coating over them that is solvent resistant and can affect appearance and adhesion. We've been sanding lenses pretty far down even around the edges starting with 400 wet and working up through 1200 to get to "virgin" plastic. Sometimes you can detect the presence of an optical coating by the fact that once cleared, it will be slightly less transparent compared to areas where the coating was removed or had degraded to the point where it was gone.

I had sanded the headlights with P800 grit wet. Maybe I didn't completely remove the optical coating. I have a 3" DA sander which would make my job a lot easier. If I do P320, P500, P800 and P1000 do you think I would be OK? Should I still use adhesion promoter?

 

[Barry]

Excuse the lateness but I wanted to check with a guy that has been doing this full time for around 10 years.
He said he has had three come back in last 5 years and what is funny, they are all done the same way and on each car only one light peeled and only in a spot and then could be feathered out.
He suspects, there were perhaps contaminates on the one light that were imbedded and just did not have max adhesion.

Does make sense as the headlights would pick up all the silicone's and oils from the road and some plastics will soak more then others.
He said he is still cleaning, sanding with 800 cleaning and shooting, as the ratio is so small he is not worried about it enough to change his prep.

 

[VB]

Excuse the lateness but I wanted to check with a guy that has been doing this full time for around 10 years.
He said he has had three come back in last 5 years and what is funny, they are all done the same way and on each car only one light peeled and only in a spot and then could be feathered out.
He suspects, there were perhaps contaminates on the one light that were imbedded and just did not have max adhesion.

Does make sense as the headlights would pick up all the silicone's and oils from the road and some plastics will soak more then others.
He said he is still cleaning, sanding with 800 cleaning and shooting, as the ratio is so small he is not worried about it enough to change his prep.

No worries at all Barry, I really appreciate your feedback on it.

Maybe part of my problem is that the original factory coating was already damaged at some point. I may have not sanded all of it off when I prepped the headlights. I could have possibly cleared onto part of the already failed coating.

I think what I will do is hit it with P320 and P500 with the DA, then finish by hand with P800 wet.

Would you recommend using the adhesion promoter first before spraying the clear? I want to do everything I can to make sure they last a really long time.

 

[Barry]

On the front lights, Brian told me that he found the adpro will weaken and he never uses it, he did say like bob said there are "some rears" and "certain mirror lights" (must be turn sigs???) he does use it.

 

[crashtech]

I know that adpro can reduce transparency, but don't know what its effect is on adhesion. We don't use it and have literally never had a comeback.

 

[NYTrainer]

I have two cars that need the headlight assemblies cleared. I only have the Euro clear. Anything special about Universal that can't be duplicated with the Euro as far as clearing headlight assemblies?
Thanks
NYT

 

[Barry]

I have two cars that need the headlight assemblies cleared. I only have the Euro clear. Anything special about Universal that can't be duplicated with the Euro as far as clearing headlight assemblies?
Thanks
NYT

Any of the clears will work just great!

 

[Paul]

I have done 4 sets of lights sanding from 400;600;800 grit and universal clear and they look fantastic.

 

[Dub]

I've sprayed Euro after 400 and 600 and 800. If the lights are not the clear glass like type 400 seems to work ok. The Clear glass like lights I have done in 600 and 800. I can't tell the difference side by side.

 

[Jim C]

no adhesion promoter is needed. always get the coating completely off then leave them with a 600-800 grit finish and you wont have a problem. dont go higher than 800.