Restricted air flow

OJ86

Promoted Users
Do you guys feel that these cheaper regulators restrict air flow?

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So I've been battling with SPI clears for a few years now. I started spraying them about 10 years ago, but the last 5 have been a nightmare with running them all the time. Its really hard to explain, but when I spray it just looks like the clear is not atomized enough and I then end up piling it on......So out of pure frustration this past weekend I finally sat down and realized its not me, it cant be. and I started looking to when the problems occurred. From what i can tell from all of the old pictures I have been searching, the problem showed up when my air regulator broke on the wall and I was in a pinch and i ran to home depot and picked this husky one up.

Now Im not certain, but I will be painting again later this week and Ill see what its like with this regulator removed.

This is how it is now:
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But that motoguard M30 will be replaced with a M60 in a few days. as the m60 has 1/2" NPT and flows way more.

I will say, when I had the husky regulator on, the pressure at my gun would drop 5psi on average from the compressor tank full to the compressor kicking on. After I removed the regulator, the pressure at the gun would change .5-1psi. so that right there is a nice sign..

I was super reluctant on even making this thread as these types of things can fill up with ideas fast, but just to be clear, I have enough compressor, I have good guns, I just cant shake these runs! I've had luck on some of the past jobs, but man oh man was it a battle.. one wrong move and boom, a run.

I just remember first shooting SPI 10 years ago and thinking, wow this stuff sprays so nice....Now I dread it.

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The only thing I can think of is that when I replaced that regulator it just didnt allow enough air by to atomize these higher solid clears. maybe im completly out of my lind,, who knows...
 
I tend to think you will see a difference. Small things like this seem important when you look at all the info posted with at the wall settings and just things in general to an air system.

I feel like I was in kind of the same boat as you, but I lack alot of experience. I always felt like I got good results but sometimes it was a struggle and I always felt like I was missing some kind adjustment.

There was a thread on here a few months ago that made me rethink my air system. I wanted to make a couple changes in my case, but I no longer have my paint booth so it might be awhile before I see if my changes help. I'm very interested to see what you find out.
 
I can't speak as to that specific regulator, but I would have very serious doubts about it.
This is a high quality diaphragm (the only type you should use) regulator that is used by thousands of shops.


Also if your coalescers and desiccant filters are working properly there is no need for the Motorguard filter on the end. That alone is causing you some restriction.
Put a proper diaphragm regulator on it and loose the Motorguard filter and I think you'll be very pleasantly surprised. Also depending on how restrictive your regulator at the gun is, this can cause issues as well. One of the reasons I started setting my pressure at the wall regulator and eliminating the at the gun regulator. Try it that way as way you may be surprised.
 
What would you say would be the loss in air pressure from the regulator on the wall to the gun with 25 feet of hose?

I run a diaphragm style regulator on my gun. The motoguard was just some cheap insurance. I was nervous ditching the ball filters years ago. and my filter system is an older unit.
 
While I agree with Chris on the Motorguard filter, It is my feelings that the regulator should be the last thing in the line before the air hose. That way, you take all the big restrictions out of the line after the regulator except for the gun, and the Motorguard filter can be a pretty large pressure drop. Move the regulator to the outlet of the filter, and the gauge reading will be more correct.

As to whether the regulator is the problem, the gauge is on the outlet of the regulator, so if the regulator is the issue, the gauge should drop substantially when the trigger is pulled on the gun. If you do not see this large drop, then the regulator is not the problem. One thing worth thinking about is the gauge. These little gauges are notorious for going bad and reading incorrectly. I would think that a gauge right at the inlet of the gun would be a more reliable indicator of what the gun was really seeing when the trigger is pulled. I am lucky that I have a SATA RP digital gun that has an electronic readout in the handle for pressure at the air cap, so I always know what my real pressure is. I will tell you that my regulator has to be set at pretty close to 40 PSI with the trigger pulled in order to get 28 PSI at my air cap, and this is where I shoot most of my work at. My little mini-jet gun requires a 35-36 PSI regulator pressure for correct fan.

The first thing I would do is get another gauge and mount it near the gun long enough to see what is actually making it to the gun. It really does not matter what the gauge at the regulator says, as long as you know where it has to be set to get the right pressure to your gun. All regulators will drop between static pressure and flow pressure, so always set the pressure only with the trigger pulled on the gun. A 4-5 psi difference between no flow and full flow, is not at all unusual. I would strongly doubt that the regulator is the source of the problem.


Regards, John McGraw
 
One of the reasons I started setting my pressure at the wall regulator and eliminating the at the gun regulator. Try it that way as way you may be surprised.

Agreed, I started this recently and very happy I did. Put two different gauges on my gun and then with full open trigger adjusted at the wall to get proper PSI at the gun. Both gauges gave the same reading which for me show about a 40 psi drop from wall regulator to the gun. In other words, I will have the wall regulator set at 60 psi with the gun trigger full open to get 23 psi at the gun. This is using going through a filter and 35' Flexzilla 3/8" air hose.
 
I never even looked at the gauge on the regulator. that wall regulator was always wide open anyways. I think this is where I dont like making these types of threads. Things get lost in the wordings.

I will say that when I had the regulator on the wall, I had to still monitor the regulator on my gun when painting for a decent amount of time and make adjustments, like 5psi or more and then back it down when the compressor filled up. Now when I took that POS off the wall I set my gun at 30psi last night and with a full compressor to when the pump kicked on until the pump kicked off(full tank) it fluctuated maybe .5-1psi with the trigger fully squeezed. Thats what lead me to believe that maybe, just maybe that cheapo regulator had been causing me all my headaches these past few years.
 
As a follow-up to my earlier post, when comparing the gun mounted gauge to the regulator gauge, you have to have your atomizing air adjustment on the gun turned wide open. If the air adjustment is closed at all, it will artificially raise the pressure near the gun when compared to what is actually at the air cap. I would think that you should have a minimum of 30 PSI at the gauge on the inlet of the gun to assure that you have enough atomizing air.


Regards, John McGraw
 
I never even looked at the gauge on the regulator. that wall regulator was always wide open anyways. I think this is where I dont like making these types of threads. Things get lost in the wordings.

I will say that when I had the regulator on the wall, I had to still monitor the regulator on my gun when painting for a decent amount of time and make adjustments, like 5psi or more and then back it down when the compressor filled up. Now when I took that POS off the wall I set my gun at 30psi last night and with a full compressor to when the pump kicked on until the pump kicked off(full tank) it fluctuated maybe .5-1psi with the trigger fully squeezed. Thats what lead me to believe that maybe, just maybe that cheapo regulator had been causing me all my headaches these past few years.

Ok, I see now. After I went back and read it, it now makes more sense. If you are only using the regulator on the gun, then my advice on the gauge is even more important, The smaller the gauge, the more likely it can go bad. these little gauges get banged around and get out of calibration pretty quick. Put a fresh gauge on the gun regulator and see if the pressure changes. I am with Chris and others, I only use the regulator on the wall. After you know where it needs to be set, there is really no need for a regulator at the gun, and it just gets in the way. See if the HD regulator fluctuates when the trigger is pulled as well. If it does not go down substantially, then is is not undersized.


Regards, John McGraw
 
It would take me a long time to get used to not having a gauge on the gun. 15 years I've been like that, lol
 
Nothing to get used to OJ. Just set it at the wall like you do at the gun. Adjust your pressure till it sprays how you want. Forget about the numbers. I love not having a bulky regulator at the end of my gun.

Read this article I posted and it may clarify some of what we are saying here.

 
i have that same husky regulator in my booth. been using that 14 years now. no issues with it BUT who knows the real origins of our 2 regulators. they could look the same but be made in 2 completely different plants in china somewhere. also i dont think mine does much regulating. i keep it wide open and just regulate at the gun.
 
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I only spray my own cars & do exactly what jc does. Other pros here will swear opposite & do beautiful work.
Changing fan width though (for me) ain't as good as when you have reg on gun & tweak it as u go vs wall.
Oj- just remove filter from motogaurd for quick bypass test.
 
I did some tests last night out of pure bordem......

Test #1 - Gun at 30Psi(RTI gauge), trigger fully fulled and let the compressor cycle all the way around with out releasing the trigger. 1psi change on the gun gauge.. Now that was NEVER the case with that husky regulator on the wall..

Test #2 - Put a brand new Digital devilbiss gauge on the same gun regulator....it read 30psi.

This picture, both of these gauges read 30 dead on.
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I tried both of these, and these were both at 40psi! I suspect because they are higher reading gauges, that down low they are inaccurate.
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Test #3, removed the motoguard filter....results 30psi. Zero change whether there was a filter in or out.


I have some parts to paint tonight and Ill update tomorrow on how the gun sprays.
 
I have not. I got the replacement desiccant yesterday along with the larger motoguard filter. I had to do some repairs on this hood since I really phuckered it up when spraying it the other day. I sprayed on 1:1 epoxy on the area I blocked out and I gotta say it sprayed really nice. Along with the clear Ive been having a real hang up with epoxy also. Today when I get home im gonna base and clear it.

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