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Main => Woodworking => Topic started by: fa001 on November 23, 2007, 02:13:20 pm

Title: air compressor ?????
Post by: fa001 on November 23, 2007, 02:13:20 pm
I just finished spraying a cab with a Wagner HVLP sprayer. I used oil based paint and it had to be thinned a lot to go through this sprayer.

So I am thinking about getting an air compressor and sprayer. Question is how big do I need? Not going to do this a lot. Would a 1 HP 125PSI 1 gallon compressor be enough?

Recommendations?

- Fred
Title: Re: air compressor ?????
Post by: BobA on November 23, 2007, 09:34:17 pm
If it was a standard type HPLV gun you need 6 or 7 scfm at about 50 psi.  A smaller touchup HPLV uses about 4 or 5 scfm at 50 psi.   Both of these sprayers are probably best served with a 5 HP  compressor with a 20 gal tank.    Only a hobby type HPLV unit for painting pictures and models could be used on a small compressor like you are mentioning.   It is all about the scfm required by the paint sprayer you choose.

You can also get self contained HPLV setups that have their own multi stage compressor and do not need the large tank an high hp motor.  The disadvantage of these units is the price.

Title: Re: air compressor ?????
Post by: sstorkel on November 24, 2007, 03:19:47 pm
BobA has hit the nail on the head: if you're going with a compressor-based HVLP gun, you need to look at the gun's air requirements and then size your compressor accordingly. Be prepared for sticker shock: most HVLP guns want a lot of air! You're probably talking a 20-25 gallon tank minimum, along with a compressor that can keep it filled. You could buy a smaller compressor, but it will run continuously which isn't a good thing. And you definitely don't want to run out of air in the middle of spraying! If you do decide to go this route, I'd suggest getting an oil-lubricated compressor. My oil-free pancake compressor makes more noise that just about any other tool I own!

The other alternative is to buy a better turbine-based HVLP system. The Wagner you were using is probably a 2-stage turbine. A 3- or 4-stage turbine will provide better atomization, though it may still have problems with some finishes. In theory, a 4-stage system is supposed to be better than a 3-stage system, but a recent Fine Woodworking test claimed that they didn't see much difference in finish quality between 3- and 4-stage units from Apollo and Turbinaire (two of the better turbine manufacturers) when spraying water-based clear coats. YMMV.

Unfortunately, if you want a good setup you'll probably have to spend $700+ for either type of system.
Title: Re: air compressor ?????
Post by: fa001 on November 24, 2007, 09:21:13 pm
Well I guess my lack of knowledge showed up in my description. The HVLP sprayer I used did not connect to a compressor. I thought that that was how HVLP was.  :P

So I am not necessarily looking for HVLP but just a standard paint sprayer that will push oil based paint.
Title: Re: air compressor ?????
Post by: sstorkel on November 24, 2007, 11:48:59 pm
Well I guess my lack of knowledge showed up in my description. The HVLP sprayer I used did not connect to a compressor. I thought that that was how HVLP was.  :P

You have a turbine-based HVLP system. There are also HVLP "conversion guns" that use a compressor.

Quote
So I am not necessarily looking for HVLP but just a standard paint sprayer that will push oil based paint.

HVLP is really the only thing that makes sense, in my opinion. Anything that isn't low-pressure will have most of your paint floating around in the air, and landing on everything it can get to, rather than on the object you're painting.

Of course, if you're not making a living building cabinets you can apply paint with a brush or roller pretty successfully...