what am i doing wrong?

There are a lot of pros and cons for both kinds of paint in the the acrylic vs. enamel debate.  Whichever side one takes, I think one would be hard pressed to find any advantage to having your paint, be it acrylic or enamel, drying as soon as it leaves the tip.  For proper adhesion, strength, and quality of finish you want the paint, be it acrylic or enamel to still be wet when it hits the model so that it can bind to the model and to itself. 

Another good reason to use acrylic paint. It dries as soon as it leaves the nozzle of the airbrush.This can be corrected by using the correct thinner for the brand of acrylic--for example Tamiya thinner for Tamiya acrylic & Model Master thinner for Model Master etc. These thinners also have a retarder to slow the drying when the paint leaves the airbrush nozzle.  Others here will disagree. This is my opinion.

Ant wrote:

im finding that as i get back into it different paints need different ratio's. so i might start thicker and go down

I use ModelMaster enamels extensively, and I find so much variation in the paint consistency out of the bottle, that it is useless to think of paint/thinner ratios.  I have had the occaisional bottle that sprayed perfectly straight from the bottle while another bottle of the same exact color needed thinning.  Other times, the paint was so thick, that I had to thin with probably 1 part paint to 2 or 3 parts thinner.  Basically, you need to thin the paint until it sprays right, regardless of any specific thinning ratio.

About your paint fragility problem, I wonder if the paint might not be drying before it hits the model.  A painting distance of four to six inches seems a little far for an AB pressure of 10-15 PSI.  When I am doing camo at those pressures, I am probably within half an inch of the surface of the model.

Between paint thinning, air pressure, distance from the model, needle position, one key thing that I would look for is how does the the paint look when it hits the model?  When I paint and things are going right, the paint has slightly wet look on the model for at least a few seconds before the majority of the solvent evaporates away, afterwhich it looks flat and dry. 

 

How about using a packet of silica gel?

thanks Mikev, the room is warm, always is, but not humid. yes with this kit i washed it twice just to be sure. i actually went back and put a thicker coat on, re-mixed paint 2:1/2 and then gave it a blow dry with the hair dryer. seems to have fixed it. im finding that as i get back into it different paints need different ratio's. so i might start thicker and go down

How warm is the area the paint is drying in?

I suggest you get a cardboard box and line it with aluminum foil and make a hole in it and install a 100 watt light bulb in the top. Put your model inside it and turn the light on and put a towel over the front of the box to keep the heat in.

An hour or so in there and most paints are completely dry.

 

 

Did you clean the model before painting?