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Thu Aug 06, 2009 8:31 pm

I have a Devilbiss FLG 3 gravity fed gun. It reportedly uses 13 CFM. I've used it about 5 years ago when a professional allowed me to use his booth and compressor. Meanwhile, I've borrowed a friend's compressor to do some body work, and was hoping to use it for painting. Unfortunately, the borrowed compressor has a 25 Gallon capacity and is rated at 5.7 CFM.
Obviously, the compressor cannot keep up with the gun.
What happens if I use this setup anyhow?
Will the paint dry before the compressor catches up? Will the gun spatter? Will the paint run?
Or can I simply be patient and wait for the compressor to catch up every 2 minutes or so?
Thanks,

Fri Aug 07, 2009 2:55 pm

The compressor will overheat and not stop running, and after running non-stop for 10 minutes (after already filled and emptied) it will never catch up.

What I do to keep my compressor its fullest is:

1. I replaced the safety valve with a heaver 150 PSI (my compressor is 150 psi max). This gives me 25 more PSI.

2. I fill the compressor and let it get cold again. If it keeps running I aim a box fan at the motor and use the tools more sporadically.

3. Empty the water out of the tank and use the minimum pressure required. (you should always regulate the pressure at the spray gun anyway.)

You really need a 220 machine. The little oil-less units are handy but not really suited for autobody painting or sanding.

Wed Aug 12, 2009 1:10 pm

I used a brand new Craftsman 26 gallon oilless compressor and water filter with the Devilbiss Starting Line series guns. I set the line pressure around 60psi. Shot single stage 3 coats and it came out fine for a first timer.

The compressor held up like a champ and the 1.6 hp motor actually caught up without any issues. I ran the compressor outside of the garage so it wouldn't heat up or ignite the gases while I was spraying.

We'll see how well the paint holds up but as of right now, it was a success! :wink:

Wed Aug 19, 2009 3:59 pm

Heres a question some what related....

My Air compressor is rated at 11.3 cfm @ 90 psi. All the HVLP Spray guns I am looking to buy require 13 cfm's. Im just shy of the requirements by 1.7 cfm's. Could I get away with purchasing the HVLP guns that need the 13 cfm's if my compressor only puts out 11.3 cfm? Will it work? Will run into any problems, or should I just say the hell with it and stay within my limits?

Any one using an HVLP gun that requires more than their compressor offers?

Wed Aug 19, 2009 4:28 pm

My compressor is rated at 4.9 cfm @ 90 psi. Had no problems painting with an HVLP rated at 13. Guns sprayed fine. A little more orange peal than I wanted, but that's what wet sanding is for.

Wed Aug 19, 2009 5:18 pm

It will work, barely

Wed Aug 19, 2009 5:39 pm

Right. It barely works if you use the recommended pressure settings at 35-45 psi. I bumped it up to 70-80 and adjusted the gun. It sort of defeats the purpose of high volume low pressure but it got the job done.

Wed Aug 19, 2009 6:05 pm

What do you mean barely? 11.3 is not that far off from 13. Any one else care to chime in?

This is an HVLP gun set I was considering
http://www.tcpglobal.com/spraygundepot/tcpgate.aspx

Its not a name brand gun per say, but it fills the requirements of my compressor. And I dont paint cars every year either.

Thu Aug 20, 2009 8:43 am

you will have to bump up your line pressure as well as your gun pressure, and you will be waiting for it to catch up alot,
and by doing that your transfer rate will be less than optimal
it can be done, but it will not be a brezze

Thu Aug 20, 2009 9:30 am

so your advice would be to stay within my air compressor cfm rating when buying a spray gun, even if it means purchasing a lower quality gun?

Thu Aug 20, 2009 10:14 am

no, buy the better gun,

Thu Aug 20, 2009 12:23 pm

Well, it seems that all the 'Better' guns that I want or I think are good all require 13 cfm, like DeVilbiss, Finish line, Binks, etc.... What a good HVLP gun that is within the 11.3 rating of my compressor? Im laying Single stage Urethane. Im not saying you have to find the gun, but who makes a good affordable gun, for someone that paints every other year or so.

What do you think of this set up?
http://www.sharpe1.com/sharpe/sharpe.nsf/Page/Finex+Plus+HVLP+Spray+Gun+Kit

Any good?

Thu Aug 20, 2009 1:45 pm

for as often as you use it, that will be fine,
The better the gun,paint ect , the better the job will turn out,
with less fighting ....