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Thread: Best method to regulate air pressure at the gun?

  1. #1
    Join Date
    Apr 2014
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    94

    Default Best method to regulate air pressure at the gun?

    I have heard of two different methods of regulating the air pressure at the spray gun.

    Method one is to have a regulator at the wall turned up high and another regulator at the gun which is used to adjust the desired air pressure with the trigger pulled.

    Method two is to have only one regulator at the wall, have an air pressure gauge at the gun, adjust the regulator at the wall so that the desired air pressure is correct at the gun with the trigger pulled.

    Is one method better than the other and why?

  2. #2
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    Nov 2006
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    Both should work, but if you adjust the pressure at the wall you will need to go to the regulator and make any fan adjustment there because changing the fan will change gun pressure. I know, I don't change the fan much, but sometimes I like to close it off and just have a cone shape. It's easy when I adjust at the gun. Only takes a second to loose the fan and then get it back again and still have the right pressure at both settings. So I vote for regulated higher pressure on the hose and choked down to gun pressure at the gun.

    Bob K

  3. #3
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    Nov 2005
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    I normally set the pressure at the wall at around 60 to 80 psi then adjust it down at the gun. This gives me control in my hand while I'm spraying but some people like doing the adjusting at the wall so that the pressure at the gun doesn't pop when they pull the trigger but I haven't found that to be a problem.

  4. #4
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    Dec 2011
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    I regulate at the gun and the wall. I noticed that if I had the wall regulator over 90PSI I could get a hard trigger pull on my gun. But if I have the wall regulator under 90PSI I get easier trigger pulls. I always run a regulator on the gun to fine tune the pressure.
    Avid collector of rust!

  5. #5
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    Nov 2009
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    I did some reading on this once upon a time. Found something put out by Sata that said if you put too much pressure from the wall to the gun, when you close the regulator at the gun to choke it down it creates a turbulance inside it that can cause irregularities. Made sense when I read it, so I keep the wall about 10 psi over what I am using at the gun so im not cutting too much with my gun.

  6. #6
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    Nov 2005
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    Quote Originally Posted by gtome View Post
    I did some reading on this once upon a time. Found something put out by Sata that said if you put too much pressure from the wall to the gun, when you close the regulator at the gun to choke it down it creates a turbulance inside it that can cause irregularities. Made sense when I read it, so I keep the wall about 10 psi over what I am using at the gun so im not cutting too much with my gun.
    I think you'll find that having the pressure at the wall too close to the pressure needed at the gun can cause atomization problems depending on the length of the hose. If the hose is 25' long and you're using HV fittings you might get away with 10 PSI higher but if you're using a 50' hose with 1/4" fittings the pressure drop could have you well below what's needed at the gun.

  7. #7
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    Sep 2006
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    How far do you guys have your regulator from the compressor & what size air line is between them.

    I assume 25' or so of 3/8" line to the gun?

  8. #8
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    Apr 2006
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    I regulate my air at wall and keep the gauge on gun wide open this way I can adjust the wall according to gun pressure. I don't know how true it is but ppg wants you to adjust gun at wall they say adjusting it at gun can cause atomization issues. I've never actually seen it happen but that's their claim so I follow their directions

  9. #9
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    Sep 2006
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    This thread got me trying to get mine dialed in better. I moved the regulator within 15' of the compressor, changed the line between the compressor & regulator to 1/2" Also lowered my compressor operating range to 90-130 psi. Even with those changes my pressure still changes between compressor cycles, hi/low. My small SRI touch up gun is perfect. I set it at 30psi & it stays right at 30. Both My GTI & Plus will fluctuate 4-5 psi between compressor cycles. It obviously has something to do with air flow as the SRI doesn't use much air.

    I would love to have the pressures stay spot on so I can stop messing with the settings at the gun.... Once less thing to think about when spraying.

  10. #10
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    Just a guess but maybe a higher quality regulator on the wall will fix it. Your big guns may be causing the one you have to operate outside it's optimum cfm capacity. It may function at 6 cfm but not be able to maintain pressure at 12 cfm. Since I don't what regulator you have I'm just guessing.

    Bob K

  11. #11
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    Sep 2006
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    Quote Originally Posted by Bob K View Post
    Just a guess but maybe a higher quality regulator on the wall will fix it. Your big guns may be causing the one you have to operate outside it's optimum cfm capacity. It may function at 6 cfm but not be able to maintain pressure at 12 cfm. Since I don't what regulator you have I'm just guessing.

    Bob K

    Thanks Bob, Its a devilbiss, but not saying its a really good one. It came with a filter / water trap kit I bought at my LPS a while ago.

    I should probably tie it off the wall & pipe it right to the compressor & see what happens. My spray hose is just a plain 30' 3/8"
    hose.

  12. #12
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    If it's to close to the compressor water vapor will pass right through it in the summer time when it's more humid. Maybe the filter is plugging up or even getting wet and restricting air flow.

    Bob K

  13. #13
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    Sep 2006
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    I did pull the filter & it looks like new & not much moisture in it at all either. But, its winter & dry as heck in the shop.

    I do not have mine hard piped. I use a rubber line from the compressor as I only set it up when I am painting. Otherwise the line is coiled up & out of the way. I'm guessing thats a lot more restrictive that 1/2" NTP pipe.

  14. #14
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    Sep 2006
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    For those of you who have perfect pressure settings at all times, can you share how your air supply is set up?

    size of lines, hard pipe or rubber, distances, equipment, etc.

    I have never had perfectly controlled pressures & I always blamed it on the fact that I never had big enough lines to the regulator.
    That could still be the case, or maybe because I am using rubber lines the pressure expands the supply line to the regulator & that messes things up? Forever I have been tweaking pressures at the gun with a cheater, now I have become obsessed with doing away with that.....

  15. #15
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    Nov 2005
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    Quote Originally Posted by 68ragtop View Post
    For those of you who have perfect pressure settings at all times, can you share how your air supply is set up?

    size of lines, hard pipe or rubber, distances, equipment, etc.

    I have never had perfectly controlled pressures & I always blamed it on the fact that I never had big enough lines to the regulator.
    That could still be the case, or maybe because I am using rubber lines the pressure expands the supply line to the regulator & that messes things up? Forever I have been tweaking pressures at the gun with a cheater, now I have become obsessed with doing away with that.....
    I have a decent Sharpe regulator about 30' from the compressor with 1/2" pipe from the compressor. I set the regulator at about 60 to 80 PSI then set my gun's inlet regulator to the pressure recommended by the gun's manufacturer. I don't have issues with variations in pressure.

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