Air Brush PSI Setting

12 psi is kind of low to get good atomization with a siphon airbrush like the 150, especially if you are feeding from a bottle.  I generally use 15 to 25psi.  The best bet is to experiment on some scrap and see what works best for you.

Don

I use 15 lbs of pressure for my Paasche H air brush I spray Tamyia, Model Master and Poly Scale works great         ACESES5                ON BENCH M50A1 ONTOS

Thx guys for your help -- i will look into increasing my air pressure a tad

--Brian

I find increasing pressure may actually increase roughness.  I usually use 15 psi, but I don't think 2 or 3 pounds will make much difference. If you go very high- 20 or so, the paint will tend to dry out more before it hits the surface.  Also, increasing the pressure may make you back off aways from the surface, which also lets it dry more before it hits, increasing roughness again.  Also, too thin a coat promotes roughness.  The wetter the coat, the smoother and glossier it will get.  Also, more thinner creates a smoother surface- try thinning a bit more.

I own a badger 155 anthem and I spray very  low for the fine detail work like camo lines and patches.  If the paint comes out a little rough at that setting you may need to thin it out a tad bit more and spray a little closer to the model.  Rough paint usually means that the paint is drying before it hits the model's surface  I use either 90% alcohol or odorless mineral spirits to thin with.  

pressure also depends on how thin your paint is. since your finish is coming out rough, you might be spraying from to far a distance. try spraying a little closer. some paints will come out a little rough though because they are very flat. a gloss coat will level it out. and also, MM acrylics are easy to over thin since they pretty thin from the bottle.