What do I thin enamels with? What do I thin acrylics with.

You can thin enamels with paint thinner,mineral spirits,that's what I always used,and most acylics thin with distilled water.

Goodness: I use mineral spriets in Modelmaster enamels and Testors acrylic thinner and Liquitex in my Poly S colors the liquitex will slow the drying time and make the acrylic colors slide through your air brush eaiser.    ACESES5

Very nice thank you very much!!!!  NOw i just need to take the messed up paint off and re-prime!!!  Maybe i will attempt this tomarrow.

I use primarily enamels.  While I have used generic mineral spirits or turpentine, I find I get the best finish with the thinner from the paint mfg.  It isn't as expensive as it sounds. I clean up with hardware store turpentine, use the mfg thinner ONLY for actual thinning. I buy Testors airbrush thinner in half-pint cans and it is not unreasonable.  A can lasts me a number of models.  Considering the price of kits today, paint and thinner are not the major costs in model building.

I know several folks who do use generic thinner, and their paint jobs are okay, but I think they would be better yet if they used the right thinner.

Don't thin Tamiya acrylics with water, distilled or otherwise. It's the least effective of all the available options.

If you're starting out with Tamiya acrylics, start with their proprietary thinner before looking at alternatives. Tamiya X-20A acrylic thinner is most economical if you buy it in their 250ml jugs.

As alternatives, one can use Isopropyl alcohol, Denatured alcohol or even Tamiya's own lacquer thinner or Gunze's Mr Color thinner. However, the behaviour of the paint is different with each different thinner and only experience will guide you. Tamiya's acrylics are remarkably flexible in terms of what thinners can be used and how far you can push each type of thinner, but to an extent, the circumstances dictate the means.

On the other hand, do not attempt to thin Vallejo  acrylics with alcohol - only use their proprietary thinner or distilled water.

Goodness180

So the other day i went and shot some paint with it and it came out terrible.  Think i thinned it tooo much cause it now looks like a spiders web on my model and looks like it just didnt adhear to the primer.  I used just regular paint thinner and now im guessing i either used too much or i should not be using that. 

It could be a case of over-thinning, excessive paint flow, excessive air flow (ie. too high an air pressure), too slow a movement of your airbrush across the surface of the model, holding the airbrush too close to the surface of the model or any combination of the above.

One of the most often offered pieces of advice on this forum is to practice on something cheap and made of plastic (eg. empty milk jugs or even old kits) before working on a "live" project. Do not practice on paper or cardboard as they absorb moisture and the paint will behave differently on the surface.