POR15 SUCKS for UV exposure, but they say that in their instructions.
I left my black POR15 coated frames in the sun for 3 weeks last August, and they got chalky. Lesson learned.
POR makes a HardNose paint that is appropriate as a top coat with UV inhibitors. They also make a GlistenPC clear coat.
Some auto paint stores carry the HardNose paint, but you'll probably have to buy it through summitracing.com or their full line of colors through their own website POR15.com. I went with Light Yellow, which was only available from POR.
I also bought some gold pearl from Custom Paints | Candy Paint - Metal Flake - Temperature Change Paint - Chameleon Paint - Pearl Paint - Clear Coat
. It worked very well mixed with the GlistenPC clear coat. Pearl needs some contrast to give it that wonderful iridescent look. Next time, I think I'll go with an orange pearl...or with a bigger metalflake or candy pearl....but the chameleon and temperature change powders are tempting!
They recommend xylene when brushing the 2nd coat. These 2-parts are slightly thicker than POR15. I would recommend 10-20% xylene for the first coat as well, to get it to flow as well as the POR15 does.
Both HardNose and Glisten are catalyzed urethanes. You mix 4 parts of paint to 1 part catalyst. I then added 1 part xylene and brushed it on with a harbor freight boar hair bristle disposable brush. Vacuum the brush well before using so it doesn't drop bristles in your paint!
This was 2 coats of HardNose paint and 1 coat of Glisten clearcoat.
POR15 is about $50 a quart, and usually available locally.
HardNose and Glisten are $60 a quart, and you have to order from http:/www.por15.com.
A local powder coater will do an NRS Bighorn frame in a solid color for $200, so this is about 1/2 the cost, I got sparkles, and did one 4-bay, one 2-bay, and one stern frame for that ~$170, and still have enough paint left over for touchups and ammo cans.
It takes about a pint to do one coat on 110lf of tubing.
2nd coat, with xylene mixed in will do 110' with about 12oz of paint (2oz xylene).
Thanks Salmonjammer for the POR15 suggestion. I hope I've added to the knowledge pool.