I've got a 100 gallon tank running off a 15hp or so motor, approx 25ft of copper line twisted around going into a standard water/oil separator, a standard paint filter right before the gun (35psi running through the lines) and I'm getting a fish eye effect in the paint. What are the main reasons for this to be happening? Thanks!

 

Main reason is because you've contamination in the paint. Grease,oil,greasy fingers,also certain deodorants can cause this.Did you clean the surface with a wax and grease remover follow by a pre paint cleaner??

 

yeah, I cleaned the hell out of it. Do you suppose I could still be getting some crap seeping through the water/oil separator? Is there a heavy duty one you're supposed to use for painting or anything?

 

silicones are a main reason for fish eyes. Commonly found in armor all and a bunch of cleaning materials for cars. If you use these cleaners on the car quite a bit especially when it's close to what you are painting you will get fish eyes. Also, if you are using a wax/grease remover cleaner make sure you do panel by panel wiping on and right back off. I have found letting the cleaner soak in without getting wiped off right away and spraying right after that causes a sort of fish eye effect. There are products you can put in the paint to reduce/remove fish eyes but I don't use them. On the first round is where you will mainly see if it's going to fish eye or not. If it does let the paint sit longer than normal before shooting next round. I usually wait 20-30 min. between rounds if it is doing it really bad. when you go to shoot on the 2nd round and so on do not put the paint on wet. kind of fan over it kind of dry and after a few rounds of doing it that way you will notice the fish eyes are gone.