It's interesting that gun manufacturers want 10 PSI at the cap but realize there is a drop in pressure inside the gun. So with air inlet set to 25-28 PSI, by the time in flows thru the internal passages drilled and perhaps some cast that resistance drops the air pressure down by the time it passes thru the air cap. This is easily overcome but why some still like siphon guns as the have less resistance and fewer passages. I have both but I don't spray all of time. I am retire mechanic and bought a cheaper Astro gravity high efficiency gun w/ PPG 2.0 cup system for it. It sprays nice and with a 75% overlap, I get great mil thickness. Pattern, pressure, fan, overlap and speed and I can spray upside down. ASE master since 78.
It's interesting that gun manufacturers want 10 PSI at the cap but realize there is a drop in pressure inside the gun. So with air inlet set to 25-28 PSI, by the time in flows thru the internal passages drilled and perhaps some cast that resistance drops the air pressure down by the time it passes thru the air cap. This is easily overcome but why some still like siphon guns as the have less resistance and fewer passages. I have both but I don't spray all of time. I am retire mechanic and bought a cheaper Astro gravity high efficiency gun w/ PPG 2.0 cup system for it. It sprays nice and with a 75% overlap, I get great mil thickness. Pattern, pressure, fan, overlap and speed and I can spray upside down. ASE master since 78.
The slower the reducer the better base lays out.