Initially, I started priming my empenage with SW-988 and enamel top coat. Then I thought about painting my empennage pieces while waiting for my wing kit to arrive. When I had problems getting information for PPG and SW paints, I found the AFS website. Since they have actual instructions and information on how to apply their paints, along with an on-line color chart, I ordered 3 quarts of two-part poly urethane and a gallon of primer. Before my wing kit came in, I managed to do a little expeimentation with the primer and painting my fiberglass parts using the two-part polyurethane.
The primer is extremely easy to work with and has the added convenience of being able to pour the unused paint back into the bottle. There's no mixing, and water cleanup is a big bonus. It does not dry as fast as the SW-988, but it dries fast enough (something like 15-30 minutes here in Texas, as opposed to 2 minutes with the SW-988). After six months, it was possible to remove the primer with MEK and a little elbow grease. I could wipe the parts with Lacquer thinner without removing the primer. However, if I used enough Lacquer thinner and rubbed long enough, it would come off. It does not chip easily, and is fairly scratch resistant.
When I tried to paint the fiberglass parts with the two-part polyuretuane, I had a few problems. I had small circles (probably due to a contamination problem in my air tank), and severe runs. After sanding off the first attempt, my next attempt was much better, but I still had problems with the paint running. Where I did not have runs, the red metal flake was absolutely beautiful. At that time, I also painted my trim tab (several times), with mixed results. One note, if you let the two-part polyurethane dry overnight, it is very, very hard to sand off. The AFS polyurethane produces a very hard surface with a nice glass finish, when applied properly.
After these experiments, I was convinced that I could paint my own airplane, but it would take a bit of practice to get it right. After finishing my wings, I managed to paint the horizontal stabilizor before starting on the fuselage. I got a few tips from Andy Karmy, and another builder who painted his whole plane using AFS. I got pretty good results on the HS, but I still had a little orange peel. I should note, that by this time, the paint was beyond its shelf-life, but it still seemed to work.
I think the key with the AFS two-part polyurethane is to get a light fog coat that you let almost dry, then apply a little heavier second coat, followed by a fairly heavy third coat. Try to keep the surface horizontal after applying each coat to avoid runs. I think this advice would probably apply to just about any polyurethane, but the AFS does take some practice.
I am into the fourth year on my RV-7A, and I still have nearly a quart of the original gallon of primer. I primed everyting except for the skins on my wings, I primed the bulkheads and the centersection ribs on the fuselage, but not much else. This is way past its shelf life, but still seems to be working, I just have to breakup the stuff on the bottom before using it. Don't worry, I'll buy a new gallon before painting the outside.
In summary, I really like the AFS paint. The primer is easy to deal with, and is fairly durable. The two-part polyurethane takes a little practice (ok, maybe a lot) to get right, but produces very good results. It is supposed to be better for you (or less harmful) than most of the other paints, but who really knows. My calibrated nose says the primer is definitely less harmful than the SW-988, but that's just my opinion, I'm not a chemist.
I should note, that I have not had any coagulation problems with the AFS paints.
Tracy.