Tamiya XF7 (red) drying with white residue?

Try less thinner.  I've never thinned Tamiya that much.  I usually mix 2:1 plus a drop of Liquitex retarder.

It's hard to say, as you don't seem to have achieved much depth of coverage. The oversprayed area on the surface behind is very translucent, and XF-7 is quite a strong red.

1:1 should be ok. You can usually go more thinner than that without any problems.

Did you stir the paint thoroughly before adding thinner?

Another possibility is contamination. Even plain water in the brush may cause "tide marks" like those in the second pic.

@ Watchmann, can't be the paint to thinner ratio, this is what most people use...

@ Phil, Yeah, stirred, shaked. Don't think it's contamination, as it's a newly opened bottle, looked like this from the beginning.

My question would be did you clean the airbrush before you used it? Maybe there is some contamination from the manufacture in there. Also it looks like your not using a primer, I know why would you on a piece of sprue! Try tesing on some card to get your mix and pressure right, I use the inside of cereal boxes. While your pressure guage may show 17psi that is at the compressor a long hose can drop that a bit so you may need to up it a little. Other than that my only othre idea would be mould release agent on the sprue.

Once your past that its down to the basics of airbrushing, distance from the peice, speed over the area and repeated runs. You didnt say which airbrush you have either, is it a named one or a generic

Phil

Hey Phil, I've cleaned the airbrush before use. It's a Badger Patriot. I've also tested on a cleaned plastic model, after putting down primer, that's when I saw the problem. Black comes out perfect, no problems at all... it's a really strange problem.

I've done a bit of digging and emailed a couple of people and found out that Tamiya's XF-7 can be a bit of an issue. From the ideas I've been given try a couple of very light layers given a lot of time to dry then a heavyer coat. I've been told this helps a lot.

Its looks like its just one of those paints which can take some work. If you can change paints try Mr Color or Testors if you can get them as I hear they are better reds. What are you painting? Does it need a gloss finish?

Phil

Thanks Mitch, good to know that it's not only me. A gloss finish would be perfect for this, I'm doing an Angel Interceptor in 1:72 (Airfix). It's a really cheap kit, I want to practice my airbrush techniques on it.

I'll try the multiple coat method this weekend, but will probably try Mr Color's one too if it's too stubborn of an issue. Thank you very very much for looking into it!