Chemical to cut headlight oxidation?

[cragar]

My friend needs to clean his head light lenses and they are plastic , does anyone know a chemical that will dissolve plastic or clean the lens to cut the oxidation , i could buff the lens but i would rather use a chemical, I was thinking along the lines of lacquer thinner.

 

[Borek]

You mean plastic got oxidized? If its surface is chemically changed cleaning them won't probably help.

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[MATLABdude]

It's either road grime, or the lenses are scratched to hell. For the first, go to a car wash, or get a bucket of soapy water and apply some elbow grease. For the second, either live with it, or buy new lenses.

 

[alxm]

Plastic won't be transparent if the surface isn't smooth, and solvents won't help that. In fact, rubbing a bit of plastic with some acetone or other solvent might just be the quickest way to turn it opaque.

I guess it's not impossible to 'buff' plastic/polycarbonate. But it's so soft, it's probably very hard. There are those companies that rescue scratched CDs for people by resurfacing them, but I think they use some fairly refined equipment for that.

 

[cragar]

ok thanks , we already cleaned it with soapy water and other stuff and scrubbed really hard.

 

[DaveC426913]

Toothpaste, especially with baking soda, is a favourite technque for reducing scratches in plastic.

 

[Borek]

Toothpaste, especially with baking soda, is a favourite technque for reducing scratches in plastic.

There is some truth in it. I am reducing scratches in plastic with toothpaste every day.

 

[cragar]

kool , thanks 4 the answers

 

[chemisttree]

You can buy a kit from many auto parts supply stores. It consists of two pieces of sandpaper of varying grit size (one fine and one really fine), some wipes to prep the surface and a liquid polymer solution. I've done this to my car and it makes the headlights look absolutely new. The opaque appearance is due to an irregular surface on the plastic surface of the lens. This is likely due to UV damage. To use the kit, you sand off this damaged surface and produce a uniform surface. The surface will appear frosted when dry but looks absolutely clear when wet. The sanded surface is filled with a polymer film former which has a refractive index close to that of the base lens material.

Costs about $20 and the kit does both lenses (WalMart Automotive dept.)

 

[DaveC426913]

You can buy a kit from many auto parts supply stores. It consists of two pieces of sandpaper of varying grit size (one fine and one really fine), some wipes to prep the surface and a liquid polymer solution. I've done this to my car and it makes the headlights look absolutely new. The opaque appearance is due to an irregular surface on the plastic surface of the lens. This is likely due to UV damage. To use the kit, you sand off this damaged surface and produce a uniform surface. The surface will appear frosted when dry but looks absolutely clear when wet. The sanded surface is filled with a polymer film former which has a refractive index close to that of the base lens material.

Costs about $20 and the kit does both lenses (WalMart Automotive dept.)

Hm. Would that work on Lexan? I wonder if that would be an easy way to clear up the windows on my boat. (We don't need curtains because the windows are so fogged.)

 

[chemisttree]

The lenses on a car are likely polycarbonate while lexan is likely methylmethacrylate. I don't know if the solvents used in the product or the polymer solution would work but at $20/ft² of treated area it sounds expensive. You might want to experiment with some fine sandpaper and floorwax!

 

[Borek]

http://en.wikipedia.org/wiki/Lexan

Seems like polycarbonate (although my first idea was plexiglas too).

 

[chemisttree]

I'm always getting Lexan and Lucite confused.