Using HVLP paint guns

[James Mills]

I'm not sure if I have enough compressor to use one of these guns.  On the side of the compressor it shows 4.8 CFM, 3.7 SCFM @ 40 PSI, 2.6 SCFM @ 90 PSI.  Will this do the job or do I have a good excuse to get a new compressor?

Thanks,


James

[Bob Zambelli]

James - depends which gun you have. I run a supply pressure of 55 PSI to my small gun. As I recall, the flow rate is around 2.2CFM. I bought the smallest gun available.

But, the best thing to do is experiment to see how it works.

If you go for a new compressor, check out some of the deals at Harbor Freight. I would suggest getting the largest 110 volt compressor that you can fit in your shop. The larger tank just means less cycling.

A new compressor, or any tool for that matter, is totally justifiable - it sure beats squandering money on useless stuff like food, clothing, furniture, etc. 

Bob Z.

[HemiGTX]

I concur wholeheartedly with Bob Z.  There is almost never a need to rationalize a new/better tool purchase.  For shooting a model airplane, you may be okay with your compressor, but I would use a siphon gun rather than HVLP.  I really don't know why people are so sold on the HVLP stuff.  To get it to atomize as well as a high quality siphon gun, you need a $300 Sharpe HVLP or, better still, a $450 Satajet (especially for metallics!).  People don't seem to realize that HVLP was foisted on us by the EPA as a way to reduce overspray/VOCs.  Professional shops use them because they are MANDATED, not because they shoot better. 

I know many people will disagree with me, but one of the WORST guns on the market is the Harbor Freight 'purple' HVLP.  Worst of all worlds.   I say this from the perspective of shooting cars, not airplanes.   

But back to your question:  a larger compressor will maintain a constant pressure at the regulator, and do it without constant running.  This reduces the temp of the compressed air and reduces the moisture in the air.  Both of these things will help ensure a good paint job. 

I would suggest nothing smaller than the Campbell-Hausfield 5 hp 60 gallon 220/1 phase compressor for painting or running air tools.  It will keep up with most tools and is very inexpensive.  I had one for several years before buying a Snap-On 5 hp 80 gallon compressor (big difference between a US 5 hp motor and a chinese 5hp motor......).  My next compressor will be even bigger.  Maybe 3 phase...

Good luck with your project!

[proparc]

5 hp 60 gallon whoa! 5 HP 20 gallon will do a car!  I just finished doing a pine bench with my 5 hp 20 gallon.  Micro Mark has a Delta brand 2 gallon compressor for $110.  A Campbell Hausfeld 5 gallon 20 gallon Extreme Duty cast iron compressor will set you back about $400. 
Marshall Palmer, who is a professional painter and stunt flyer here in Socal gave a great tip.  Don't buy hvlp spray guns for hobby use.  They use too much air, and our model airplanes are too small.

[James Mills]

I concur wholeheartedly with Bob Z.  There is almost never a need to rationalize a new/better tool purchase.  For shooting a model airplane, you may be okay with your compressor, but I would use a siphon gun rather than HVLP.  I really don't know why people are so sold on the HVLP stuff.  To get it to atomize as well as a high quality siphon gun, you need a $300 Sharpe HVLP or, better still, a $450 Satajet (especially for metallics!).  People don't seem to realize that HVLP was foisted on us by the EPA as a way to reduce overspray/VOCs.  Professional shops use them because they are MANDATED, not because they shoot better. 

I know many people will disagree with me, but one of the WORST guns on the market is the Harbor Freight 'purple' HVLP.  Worst of all worlds.   I say this from the perspective of shooting cars, not airplanes.   

But back to your question:  a larger compressor will maintain a constant pressure at the regulator, and do it without constant running.  This reduces the temp of the compressed air and reduces the moisture in the air.  Both of these things will help ensure a good paint job. 

I would suggest nothing smaller than the Campbell-Hausfield 5 hp 60 gallon 220/1 phase compressor for painting or running air tools.  It will keep up with most tools and is very inexpensive.  I had one for several years before buying a Snap-On 5 hp 80 gallon compressor (big difference between a US 5 hp motor and a chinese 5hp motor......).  My next compressor will be even bigger.  Maybe 3 phase...

Good luck with your project!

Have you used the automotive clear with the siphon gun?

James

[john e. holliday]

I have used the two part auto clear in an airbrush for the top coat.  My touch up gun puts out too much material with the clear.    DOC Holliday

[HemiGTX]

James, the answer is a qualified 'yes.'  I have shot 2 part clears with a siphon gun, but not the latest ones (I've only used HVLP with them due to compliance issues where I was shooting).  I can't foresee any problems using the new clears with a siphon gun.  In fact, you'll probably encounter more problems with a cheaper HVLP gun, in my experience...
A few years ago I bought my 5 hp 60 gal Campbell-Hausfield from Harbor Freight for $399.  Last time I checked (maybe a year ago?) they'd only gone up a couple of dollars since then.