can you use enamels in an airbrush and if you can hoe much do you have to thin the paint

Yes you can. I would thin it so it looks like milk. I usually thinn my paint to 60% paint to 40% thinner and set the air pressure at about 30 PSI.

ok thanks

Howdy 'Nick,

animal's correct. The only other thing I can add (and I'm searching ) is, the pressure setting.
If you're generally spraying your model, approx. 30psi. sounds great. If you're 'walking' a camo separation line for example, I would adjust your pressure downward a tad. The same for any 'fine work' you might be considering, like interior, cockpit, engine compartment, rain lines, rust streaks, etc.
And just to throw it out there......I've also turned the pressure up a tad and not thinned down my paint and 'splattered' either a dark brown, or a buff colour on the lower half of my chassis instead of using an old tooth brush. Works good, as long as you don't get impatient, or, you have fine eye-hand coordination.
It sounds a little more complicated than it is.

Tread.