" thinning other types of acrylic paints with a combination water, alcohol and a drop or two of liquid dish detergent. This dish detergent helps break up the surface tension of the water, that otherwise might cause your acrylic paint to bead up on the surface of your model."

Ok, everyone share your ideas of how to thin acrylics so I can start playing with a badger 350 I bought to learn how to airbrush.. I've got a few tanks that are going to need ambush camo on and I need to practice. ;p

I hear very odd combos on how to thin acrylics. I use tamiya color and vallejo paints currently. I noticed that vallejo have a "air" line that are supposed to be used for airbrushing. Not sure if these still need thinning, but based on the results I get with their standard paint, I want to try these.

GlasPlus is terrific for thinning acrylics. It does the same thing as dishwashing detergent without the suds. :-)

Cody

I only use isoproynol for thinning tamiya paints for airbrushing. It gives me the results I want, never had a problem, so i just stick with it.
I use "ajax" or "windolene" window cleaner for cleaning out the brush afterwards, but I know a lot of guys actually use this for thinning tamiya paints. Make sure its the clear stuff and not the version with a blue tint. This tint cold affect lighter colours.

I've found that the type of thinner required depends on whether the acrylic paint in question is truly water-based, or only water soluble. For example, Tamiya is the latter. It is alcohol based, but water soluble. What this means is that you shouldn't try to use water to thin it. In my own personal experience with Tamiya, I have found that I get better results using their thinner than isopropyl alchohol. This is because the paint seems to dry quicker with alcohol than their thinner. In fact, it can sometimes dry in mid-air before it hits the surface. This creates the very rough orange-peel effect many complain about with Tamiya. Tip drying can be a problem as well. I've not had these problems with their thinner. Windshield fluid is preferred by many with Tamiya, but I've no experience with it.
Vallejo and Polly Scale, my two favorite paints, are truly water-based. This means that distilled water works fine as a thinner. In fact, because a water-thinned mix is "wetter" than an alcohol mix, I get none of the aforementioned Tamiya problems (except perhaps a little tip-drying, but nothing serious). A drop of detergent does seem to help the flow and perhaps it slows the drying a bit (not sure about this, though). Personally, I don't recommend the Vallejo air line. This is because it is pre-thinned with their thinner which means that if you have to thin it any further, you can't use water (or at least I've had no luck doing so). Plus, it is much less versatile than their model color line. Model color brushes wonderfully and in my opinion is easier to work with in terms of airbrushing than their model air line. So, what's the point of the latter?
One of the nice things about acrylics is they are much easier to clean than enamels, so experimentation is easier. Plus, the water based paints are truly non-toxic (Tamiya may not be as bad as enamels, but I still think it demands ventilation to a greater extent than paints like Vallejo and Polly Scale). Once you get the hang of acrylics, you probably won't go back to airbrushing enamels on a frequent basis.