On Sunday, January 24, 2016 at 12:32:25 PM UTC-5, wrote:

For acrylic urethane I use a turbine HVLP system which gives a big pattern and has no water in the air. I can't make myself use my $400 gun for polyester topcoat so I do get a few fish eyes in that.
FWIW
UH

I know guys that are serious about painting are particular about
what goes through their guns -- never put primer through their
favorite gun and so on. But what's the rationale for this? It
seems to me that the paint follows such a short path through
the gun that it can't cause any serious wear. At least for
gravity feed guns. Are there other issues?

Jim Beckman