They do different nozzles for this, I'd suggest trying to get a 'High Flow Nozzle'
http://www.mikes-models.co.uk/index....?filter_id=139
This is a guide to what nozzles you should use for what
http://homepage.mac.com/srogers4/hob...h/nozzles.html
Thinning the paint with AutoAir Reducer
http://www.everythingairbrush.com/ac...0ml__4oz_.html ( it's the medium one you want 2nd from bottom on this page ).
Then combine this with a better compressor and 40 - 60 psi and you'll be getting on much better.