I just finished some test strips of a product I've recently found and the results are promising. It's called GAC 200. It increases adhesionand reduces the tack of artist paints for the application to rigid and smooth surfaces. The test strips have a good finish, with no tack and the same gloss that the paints usually have. The instructions say to mix 50% to 75% into the paint, and thin with water. I tried both mixes with Golden heavy body artist acrylics thinned and sprayed through an airbrush. 10 mins. and they were dry to touch, no tack whatsoever. The 50% mix does have more opacity. My previous attempts to use Golden paints on styrene, thinned with Golden airbrush medium, left a tacky finish. I will be playing with this product more, and will try to follow this post with more info as it accumulates. If anyone decides to experiment, please read all warnings on the paints as some are not suitable for airbrushing due to health risks.