Steve, believe it or not this $15.00 Harbor Frieght gun works pretty good.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=47016
I picked up a couple for the machine painters at work and I tried one out spraying Polane (similar to Imron) and it work just as good as some of my guns I use at home for painting cars, airplanes, motorcycles etc. These cheap knockoffs are a lot better than they used to be. FWIW, I prefer these gravity fed new fangled guns over my older suction feed guns. To get the best finish out of most guns, it is usually best to crank the pressure up to at least 50 psi even though the directions on the paint or gun may suggest lower. You will get better atomization of the paint for a better finish, but will waste a bit more paint. (good for the finish, bad for the EPA nazis
)