Pressure drop while spaying HVLP gun

by Robert Matthews

I am running a Craftsman Single Cylinder Oil Free 6hp 30 gal compressor (8.6 scfm at 40 psi 6.4 scfm at 90 psi.)

My gun is rated at 9 scfm at 35 psi, 12 cfm at 43 psi. I have used this set up for over a year with no problems. In the middle of spraying the other day the pressure of my gun started to drop while i was spraying. I released the trigger. When I pulled it again the pressure was there but only for a sec or two. Then it would drop to almost nothing and paint would barely come out of the gun. Every time I released the trigger for a few seconds and then pulled it again the same would happen. I hooked another gun up and the same. My blow nozzle does the same but not as drastically. Why is this happening.
Robert, it seems that something is blocking the orderly flow of compressed air to your HVLP paint gun.

That, or, the ability of the compressor to maintain flow has been compromised... something is failing.

You may have a regulator problem, but since I don't know what else you have in the discharge manifold of your compressor, that's only a guess. I would remove the regulator from the circuit and see if that made any difference to the flow to the gun. If you have another regulator, replace the existing one as a test, perhaps?


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Can i run hvlp paint sprayer?

by elda
(dawson pa)

can i use a hvlp paint sprayer with central pneumatic 2hp 8 gal air compressor
The answer is yes, of course you can, but you may not be happy with the result.

A HVLP paint sprayer uses low pressure air, and it has a minimum compressed air supply flow rate to operate properly, and that is the info that you have not supplied.

What is the pressure requirement of your HVLP paint sprayer, and what is the flow requirement in CFM?

Knowing this information, and also the output of your air compressor, will help you determine if you can run your HVLP paint sprayer.

Without that info, your question cannot be answered accurately.



Comments for Can i run hvlp paint sprayer?

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Jul 26, 2011
using hvlp with small compressors
by: Joe H

yea you can spray with smaller compressors but you'll end up with a shitty orange peel textured finish,so I really don't recomend it.Unless its base/clear u can always block the clear to a smooth finish with 800-1000 grit sand paper using water,then polish then OK. But if using metallic or pearl colors you will need more air to evenly lay out the pearls and metallics.

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Filters and plumbing air tools

by Herb Frye
(Hopewell Township, PA)

I bought a used compressor that I want to use for some painting and also run air tools.

It dose not have any kind of filters. I looked at a filter that was dual for removing water dirt etc. but also added oil for air tools.

I don’t want oil in my paint. Do I need separate filters and a separate lubricator? Do I need to use separate air hoses etc.?

Hello Herb. Thanks for visiting.

Plumb the discharge line from your compressor into a manifold.

Take one feed from the manifold through a general purpose air filter to your air tools.

Take another feed to your spray paint equipment. Upstream from the spray gun, install a coalescent air filter to remove any transient oil that's coming from the air compressor.

You might consider an in-line compressed air drier next, and then plug that into your air tool lubricator, which should be installed right before your air tool.

Hope this helps.



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Need impact gun for wheel lug nuts.

by Ron
(London, Ont, Canada)

Using an air impact gun to remove/install wheel lugs on passenger cars

Want to purchase appropriate compressor and impact gun to change wheels on 2 or 3 vehicles twice a year (exchanging snow tires and regular tires).

Some impact guns produce approx. 275 psi torque while others are rated much higher (approx. 450 psi) but both appear able to remove/install lug nuts.

Those that I have looked at all appear to need just under 6 cfm at 90 psi which means I would need a 2 hp compressor.

1. Am I correct in assuming that a 2 HP with a 30 gal tank would be less costly to run than a 20 gal as it would cycle less often?
2. Are oil filled compressors better than oil-less?
3. How much torque is typically required to install/remove passenger car tires - using only the impact gun?
4. Will electric impact guns install/remove wheel lugs using only the gun?
I will have other applications such as inflating tires, etc. which will require less air that the impact gun.
If you are getting 6 CFM of flow from your compressor, and your impact wrench needs that flow, then theoretically, the air being generated by your compressor should power the wrench.

If you have xx amount of air in a tank that's already pressurized in excess of that 90 PSI, then your gun will run for a few seconds before the compressor comes on, as the pressure in the tank drops.

I question the ability of your 2 HP compressor, running on 110 Volts, to generate the flow you need.

Re: #1) that depends on how much air you are using over what period. I'd default to the larger tank to be able to run my tools better.

#2) Depends. As I note on this website, with the developments in oil less compressors in the last few years, and the fact that their price is now commensurate with oil lubricated compressors, when I buy my next one it will be oil less.

#3) No idea.

#4) Possible. I don't know. I've never seen an electric lug nut wrench in a tire shop. That should tell you something.

There is much more info on the Sizing your air compressor page on this site.

Be aware too that you can only get so much power out of a 110 Volt circuit, regardless of how big your air compressor is. Your compressor size is limited by the power supply.

Cheers Ron, and thank you for writing in.


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