Replies

1. 
   Westchester | Jun 25, 2003 03:46am | #1

   Hey Bird,

   I might think about not applying a top coat of finish.  Is it possible to leave it as is or is finish an absolute requirement?

   SA

2. 
   Paul_Snyder | Jun 25, 2003 03:57am | #2

   Ronan paints has some clear exterior sign paints. A search at google.com should turn up some suppliers.

   Paul

3. 
   Kevin | Jun 25, 2003 04:19am | #3

   Is the existing paint acrylic latex, acrylic lacquer or acrylic enamel? If one of the later two... I'd ditto SA and suggest you leave it as-is. Cars and trucks were factory painted with acrylic lacquer for years. I'm assuming that the existing paint is a pigmented color rather than a clear acrylic finish. If that's the case... I'll further assume that by "yellowing" the concern is with color fade over time? If that's the underlying concern than it won't matter much what you put over it. Certain pigments fade faster than others. Color fade is a fact of life with virtually any exterior paint. That's why bodyshops typically charge extra to custom fade the paint for repairs on an older vehicle. Pulling up an exact match to the color as it looked exiting the factory is easy. But, it won't match exactly on a vehicle that has been exposed to sunlight for a few years. Of course different colors do this worse than others because, as I said, certain pigments fade faster than others.

   Regards,

   Kevin

1. 
   ndege | Jun 25, 2003 05:53am | #4

   My friend is using artist's acrylics--I don't really know how they're made but I always thought they were some kind of latex. She has heard of products that protect the colors from UV, a marine polyurethane but it's oil-based and will yellow in time. I wonder if the paint won't fade first.

1. 
   Kevin | Jun 25, 2003 07:57am | #5

   I'm certainly open to being corrected on this... but, I believe that what UV resistant coatings do is to protect the chemistry of whatever coating it is protecting from breaking down under UV bombardment. But the pigments that are exposed are still subject to fading, albeit slowly.

   It does sound like your friend is using acrylic latex. As for an alternative to the marine polyurethane, perhaps an industrial or automotive polyurethane would work better without the yellowing? I've got a gallon of the newest IMRON (by DuPont) water-based clear polyurethane at work that my jobber gave me to test out. It doesn't require a catalyst and dries very quickly. It also has amazing adhesion properties. I tried it on both prepped and uprepped substraits from PVC to aluminum... plastic laminate to plexiglass and wood too. I couldn't get it to let loose from any of it regardless of whether I'd prepped or not. The only thing that it failed on, and it failed badly, was over an automotive metallic basecoat. I called DuPont and they suggested that I catalyze the basecoat and that did the trick. I couldn't even get a minor adhesion failure on the cat. base coat. I was quite frankly very impressed. It's expensive, though. And it was a pain to clean out of my Sharp HVLP cup gun. But, in terms of performance... especially adhesion, I've never seen anything like it.

   Regards,

   Kevin

2. 
   Paul_Snyder | Jun 26, 2003 01:28am | #6

   Something like Aqua Clear Lok UV (http://www.ronanpaints.com/clear.htm) has the properties you're looking for. It contains UV blockers and HALS to protect the underlying paint and the clear finish itself. It's water-clear and non-yellowing.

   I always thought acrylic paints and finishes were based on acrylic resins - no latex involved. But I'm not that deep into the chemistry.

   Paul

   Edited 6/25/2003 6:30:40 PM ET by Paul S

1. 
   ndege | Jun 26, 2003 02:52am | #7

   Will pass along your ideas and thanks for the tips!