How/where does one measure the PSI for your spray gun?

I have 100 psi coming in from the compressor. This pipes off through a pressure regulator (not a flow regulator). Let's say I set that at 35psi.

Then I have a pressure gauge at the spray gun. Do I adjust so that it's 35 PSI when the gun is spraying or when it's not spraying?

  • 2
    If it's a good pressure regulator, spraying or not spraying makes no difference. That's the whole point of a regulator.
    – Ecnerwal
    Aug 28, 2023 at 2:22
  • So there's a regulator at the compressor (set at 100 psi, as it's a multi-use regulator), and a simple turn valve (not a regulator) at the gun, with a pressure gauge. Should I put a 2nd regulator at the gun.
    – LarryBud
    Sep 1, 2023 at 15:44

1 Answer 1


You set your regulator. Then you spray.

If the spray pattern is not to your liking, then adjustment are made to the fan size and density. You may then need to adjust the pressure as well.

You did not indicate what gun you are using, so it is impossible to be more specific.

  • Are you suggesting one not look at the actual PSI at the gun and only the result?
    – LarryBud
    Sep 1, 2023 at 15:45
  • You set the PSI to the recommendations for what you are spraying, but that is not the ONLY adjustment. The final determining factor of where the pressure should be is determined by the end result. You said you have a pressure gauge at the spray gun . Set that at the desired pressure without spraying. Test spray and adjust pattern and density AND if needed the pressure. Hopefully you have a pressure regulator with gauge at the air inlet of the gun.
    – RMDman
    Sep 1, 2023 at 16:19

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