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Old 01-10-2011, 05:06 PM
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[QUOTE=cjperotti]You may be right, although, I’m not totally convinced.

Here’s my problem. All single stage automotive paint regardless of whether its enamel, urethane or acrylic lacquer is labeled as UV protected.
As simple as possible, ALL SS paints have UV inhibitors added.
SS paints are nothing more then clear with a dispersion additive to keep the pigment from settling out.

Urethane clear however, unless labeled otherwise is not. Meaning no additive has been added obviously.

ALL Urethane clears have UV inhibitors added, there is a 30 year old saying, the most expensive thing in a gallon of clear is the UV inhibitors.
Most automotive clears have two different UV's added.
UV additives can range from $10 a lb to the high side for a 479 of $179 a lb.

The reason this is a problem is that I find it hard to believe that any of these corporations would spend the money to add an additional additive when it is notoriously known they chinch on everything they produce. Therefore, If they’re not adding a UV protectant as I seriously suspect then I can only assume the pigmentation in the colors is the reason for the protection they claim.
If I can defend all of the accused, if UV inhibitors were not added and lets take a silver base as not to be extreme, like a red or black and also assume the base color of silver is a 7-8 fastness rating, that is considered the best and most expensive pigment. Fastness is a rating of heat and color hold out and another example would be say a 5-6 rating, industrial grades that are normally used for items that stay inside, such as phones, computers, lamps, in other words not exposed to the suns UV rays, remember UV's do not bend, you cannot get a sun tan laying under your car or in the house.

We spray this base with the best clear money can buy but it has no UV inhibitors, here is what we know.
Silver, in the SW or SE with full sunlight every day, the color will be dead inside of 2-4 weeks, up north might go a month.

The resin plays more of a role in this then the UV inhibitors, the more clarity the core resin has the more it costs, it is very expensive to go with the best but still not as expensive as UV's.
Can UVs cause yellow cast, sure but unlikely a company is going to over do the UV as one they are very expensive and two you get to a point of no payback.
Ciba recommends a percentage of both kinds by weight of solids and of course the higher the solids the more uv's are used if it is a good grade clear, games do get played in this area for sure.


Hope this helps.
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