Hi guys, I've been airbrushing on and off for a few years but suddenly I am now getting a strange "mottled" sheen on the surface of the paint. It is only visible when the light hits the surface at certain angles and the surface itself seems smooth enough.

I tried airbrushing matt varnish over it but the matt varnish has the same thing. Any ideas on what's causing it? I've not had this before and I'm not doing anything diferent with the airbrush or paint mix that I can think of that would cause it.

I've got that a couple of times when I applied too much paint in one coat or pressure was too high. Just a guess.

It's fairly common if you get too close with "rattle can" paint application.

P.S. If you have a Dremel/Moto tool you can try buffing it to a gloss finish then reaply the top coat.

Looks like the grainy effect you get with over pressure. I seem to get this a lot with tamiya but no problems with humbrols. As you´ve obviously been airbrushing for some time, and not had this problem, you would know how your set up works best. Check it to be sure. Maybe could be something to do with humidity??? Maybe the paint is drying quicker in the air??? Did you wash the kit first? Maybe it could be some release agent still on the surface. Maybe if you go over your normal routine and see what circumstances/subject has changed, it might lead to the answer

Air pressure, I bet that's it! My airbrush was playing up and I found a leak in the airpipe. I recently taped over the hole as a quick fix so now the air pressure to the airbrush will have gone up. DOH!
Thanks for the quick replies and help guys.