Headlight UV layer is as thin as food wrap. Is it safe use sandpaper to clean it?

Question

Do people who suggest using sandpaper to remove oxidation on headlights even realize how thin the UV layer is and how important it is to the clarity of your headlight lens?

Or do they even understand plastic headlight lens are a composite of two layers and why they are made that way?

Answer 1

If the outer layer of your headlight lens has oxidized, you are pretty much going to lose whatever is in that outer layer. The light transmissive qualities of the 'UV layer' are probably the lowest on your level of important considerations.

I would NOT use sandpaper like this.

Possible alternatives - lens polish.

you can get stuff specifically for headlights at a specialty detailer's. It's something like diamond polish or similar. Get the three-step one and check the grit. Some are 5-step, but only contain 3 steps of actual polishing.

You need something finer than 4000 grit sandpaper. I would suggest trying whatever you want to try on a dead CD before moving to your headlights. Make sure that it gives the quality of polish that you are satisfied with.

Take care as to how you apply the polish too. Don't press too hard...

On the other hand, you are not likely to ever get that 'factory gleam' back.

Don't forget to apply a decent quality wax to protect plastic headlight covers... it will dramatically extend the life.

Incidentally, I do photography and own a handful of Canon Pro 'L' lenses and I wouldn't say that a UV filter is really as important as you seem to think. The headlight reflector plate shaping, as well as the general transmissive qualities of the headlight lensing material as well as the cut patterns are going to have much more of an effect.

Answer 2

People do not realize how headlights are constructed. They remind me of the mechanic who rebuilds an engine and is left with a bunch of extra parts.

Headlights have made three major changes in the last 20 years or so.

They went from one piece refractive glass sealed beam to the composite refractive plastic lens.

Now they are still plastic composite but no longer refractive.

You cannot apply ancient science to todays high tech problems.

The automobile manufactures wound not have put a UV layer on headlights if it was not a necessary expense.

Its plastic so it does not degrade as fast as other materials and unless physically removed it will remain a party of the lens as one piece.

Once the UV layer is removed the lens begins to yellow and show signs of age.

Ignorance of headlight construction is the reason so many people will say use sandpaper. They mean well but they just don't understand what is at risk.

Answer 3

Most people do not have knowledge of how a headlamp is constructed glass or plastic.