tamiya acrylic paint mix ?

I find using ratios hard to do as each can of paint seems to be different. I always try to thin it to a skim milk like consistency.  I usually pull a little paint up the side of the cup and if it runs pretty freely it works about right. Sorry I can’t be more specific.

I'm using Tamiya acrylics for the airbrush now too, and I've got to agree with Hercmech; very hard to keep a set ratio.  You've just got to thin until it's right. Go for that milky thickness & try it with your airbrush setup, on a piece of cardboard or scrap plastic, make adjustments from there if needed. It's a dark art that just needs a little practice!

Tamiya isn't my main paint, but it definitely has its place in my arsenal.

Ratios vary due to preference, airbrush, and environment.

Personally, I prefer to thin Tamiya with their lacquer thinner or Gunze-Sangyo Mr. Color Thinner or Mr. Leveling Thinner. I've just found that they spray better through my Iwata than with acrylic thinners or alcohols.

My default ratio is 2:1 thinner:paint. The beauty of Tamiya paints is that you can thin the heck out of them and they still spray well. When I do post-shading, I take it as far as 9 or 10 parts thinner to 1 part paint without problems. Can't say the same about other acrylics.

 Practice makes perfect. The 2-1 is a good place to start but checking the consistancy on the side of your mixing cup for that SKIM MILK consistancy mentioned above is the best way. You will get the hang of it just by playing with it. Try to find the Tamiya thinner with the yellow cap -or- Mr.Hobby 250 for the best results.

As mentioned above, there's no exact ratio for thinning Tamiya acrylics  (or indeed any type of paint). How much you thin it will depend on your airbrush setup and the type of painting you're doing. In my experience, Tamiya's acrylics are very flexible in terms of how much you can thin them and what type of thinner you use.

DoogsATX

The beauty of Tamiya paints is that you can thin the heck out of them and they still spray well. When I do post-shading, I take it as far as 9 or 10 parts thinner to 1 part paint without problems. Can't say the same about other acrylics.

I concur, though if you thin with Tamiya X-20A thinner, you will not be able to thin much more than about 4:1 (thinner to paint) without the paint tending to bead/run and lose adhesion. If you thin with denatured alcohol or Tamiya's or Gunze's lacquer thinners, you can achieve the highe thinning ratios, as they seem to "wet" better than Tamiya's proprietary X-20A thinner. 

One thing that you do want to do is spray from a close distance when using Tamiya's X-20A thinner, (or Isopropyl or denatured alcohol). When using these thinners, you want to maintain a distance of about 4-6 inches from your airbrush to the subject otherwise you may encounter problems with the paint drying in mid-air between your airbrush and the surface, resulting in a dusty/grainy finish.