What size compressor for spray gun

[joesquid]

Hey guys and gals,
I've got a Craftsman 4hp, 13 gallon, 125 psi air compressor and intend to paint my coke machine with a small automotive detail spray gun.  Will my compressor provide enough air volume to properly atomize the paint?  What pressure should I maintain?

Thanks!!

[loman4ec]

I am sorry joe but the air tank is way too small. I have a 32 gallon and it isn't enough to do the job. You are going to need a compressor that will be able to deliver constant air flow over a long enough period to paint the machine.

[joesquid]

Josh,
Thanks for the info.  Very disappointing but glad I found out before buying paint.  I was really psyched about doing my own paint too.  So what size compressor do I need, one of those 60 gallon 240vac bohemoths?

[loman4ec]

Yes you will need something large like that. Now I have heard of some of the really expensive HVLP guns having less air consumption but I don't know if yours is enough for that. The problem is lack of air supply. In mine I can only run my DA sander for less than a min or two before it needs to fill the tank up.

[BryanH]

Eric, I have a 33gal / 6HP from Sears.  So far, its has been capable of keeping up with consumption of my HVLP gun.  The compressor is rated for 8.6 SCFM at 40psi and the gun only needs 7.0 SCFM.  The compressor does run short on air when using the sander.

[joesquid]

What about the 9 gallon RIDGID compressor I found at Home Depot?  11.8/10.3 SCFM @ 40/90 psi, gas operated.  I like it because it's portable and doesn't require a 240 VAC power source.  Yeah, $750 price tag but I just bought a $1000 dining room table for my wife AND my birthday coincides with Father's Day this year soooooo.....

[joesquid]

Here's a link to this compressor
RIDGID GP90135

[loman4ec]

I am not an expert at this but I think the problen lies with supply of air. An air gun would use up the air in those tiny tanks in a matter of seconds. As stated above even our 33 gallon tanks can barly keep up. So if ours work for painting why not get a craftsman like ours. They are 110v and cost under $400 from sears and are on wheels.

[BryanH]

Eric - despite the fact that the volume #'s say that compressor should work, a 9 gallon tank seems small. I'd have to agree with Josh, but I'm no expert.  If you've got the bills to drop on the Rigid, then I'd try to find someone knowledgeable about painting with these things and ask them.  Then cross reference it with an unbiased decision.  I've found this DIY forum or this ask the expert site to be helpful for these kinds of opinions.

[MoonDawg]

Eric. Ask around, sometimes body shops will rent their spray booth by the hour.  You normally would spray on a Saturday afternoon, and pick up your stuff Monday AM

       That way you could decide how much equipment you want to buy after your first paint job.

[joesquid]

Glen,
Great idea!!  I hadn't thought of that!  I'll ask around!

Josh,
Perhaps i'm too far in the weeds.  I guess my question is, What portable compressors are you guys using for paint?  The 60+ gallon units are not an option for me as I live in military housing and cannot add another 240VAC line to the garage or house.  Also, as I move around alot (gotta love the military life) portability is a must.

Thanks for all the help guys, it is appreciated more than you know!!!

[BryanH]

Eric - we're using 33 gallon Craftsmans that are portable 120V machines (see this thread on compressors).  Anything larger than these from sears is 240V and hardwired.  The manual says that you should/might be able to run it off of a 15A circuit.  I couldn't find any 15A in my house that didn't cause the breaker to throw so I did end up running a new 20A circuit into the garage.

Personally, I've used mine with a HVLP gun to paint hammerite and primer with pretty good results (given that I've never painted anything before).  I plan to try and paint the outside finish with it also...  but I think I'm going to get a gravity feed HVLP first (I think they use even less pressure and less paint than siphon feed).  

Have also used it for sander but it does run out air and need some catch-up spells for heavy sanding.

[Skeleton Man]

I see a few people here use air powered sanders..  is this simply coz you own a compressor, or because they work better than electric ?

[joesquid]

Honestly I think DA sanders are more efficient at sanding than regular electric sanders.  I love my DA sander......there are many like it but this one is mine and it's name is "Charlene."

[joesquid]

I finally got a chance to review one of the DIY websites listed by Bryan a few posts back and stumbled across some interesting information.  Has anyone ever used an electric HVLP paint system?  Check this out, I wonder if it can be used for automotive paint?
electric hvlp sprayer system