First-Timer trying to learn how to paint.

Hi ferni5 !

What you want to look for when thinning paint for airbrushing is to attain a consistency similar to that of 2% milk.
Dip the tip of your finger in 2% milk and observe the drop that hangs from the tip of your finger, observe how it reacts when you wiggle your finger slightly...taht will give you a feel for the needed consistency for airbrushing and you then try to attain the same consistency when thinning your paint. You will develop a feel for it as you gain practice time. It's a starting point. Then with experience you will learn the subtleties of thinning different paint brands, types, and even colors within a given brand.
It all comes with practice and experience.
Happy modeling !

Thanks for the help. Really, thanks Mike and Music City.

Mike's right (of course he's right, he's Mike!). You can certainly paint straight from the bottle, but you'll have to use a lot of pressure to get it to spray properly. Thinning will allow you to use a much lower pressure.

I've had good luck with either Tamiya or Textors Model Master acrylic thinning them 3 parts paint, 1 part isopropyl alcohol. It will dry to the touch in just a few minutes (especially if it's flat paint) but it still needs to cure. I normally leave mine about 24 hours before I do anything with it, just to be safe.

Also, don't cut your single-action brush short. There is nothing wrong with a single action, and you will get great results from it. Just remember that it's more the guy behind the airbrush than it is the airbrush itself. Practice and enjoy!

Some paints are thin enough right out of the bottle but they may require higher pressure to atomize well enough. If it comes out grainy looking then it may be too thick and you may want to try thinning it 2:1 for starters with either isopropyl alcohol or a 50/50 mix of alcohol/filtered.

Mike