Thread: Hazing Headlight Lens
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Old Jul 14, 2010 | 11:18 AM
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onehundred80
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From: Ontario
Unhappy Re: Hazing Headlight Lens
Originally Posted by maxcichon
Very interesting.

You wouldn't happen to have an actual NAME for this product, perhaps?

And BTW-I spoke with a good friend (plant manager in the automotive injection molding business. A pretty knowledgeable guy) a while back about this. He said the UV protective layer is applied (sprayed) into the mold immediately after the release agent and immediately before the hot polycarbonate is injected. It is not an after-manufacture treatment.
I worked in the injection molding industry (mold design) and the plastics have an agent in the material to delay damage from the suns rays. Without this the plastic would discolour through out and the lens could not be refinished. This damage will eventually occur as it is just a matter of time, plastic is poor in this regard, it will basically break down and get discoloured and brittle.
Any spray on agent with any depth would be subject to delamination and be obvious to the eye. Remember that the surface of these molds are polished to a mirror finish and any spray would have a lesser finish.
A frequent hand buff with a proper lens polish would keep the oxidation in check by removing the microscopic layer as it appears.
There are treatments for plastics that involve spraying on a volatile liquid that liquefies a very thin surface layer, the layer flattens out and the liquid evaporates leaving a better than molded surface. Expensive, as it requires a dust free environment, maybe even a near vacuum.
To keep the lenses in top shape keep them out of the sun. It is possible that some lenses were made using off grade plastic, or a poor molding process, these would be hard to prove and its too late now anyway.
 
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