Air-Line Drying Options

Advice on setups to extract water from your sprayer air supply system. September 10, 2007

Question
I posted earlier about the issue of spraying CV. What would be the best way to remove water from my air source? I have a large compressor outside with a Devilbiss extractor at the compressor. From the extractor I run a 25' air hose to my Kremlin pump. Suggestions on what I should change/add? Also, what parts on the extractor should I maintain/replace? I've had it for awhile and haven't done anything to it.

Forum Responses
(Finishing Forum)
From contributor J:
I'm just learning about this stuff myself, but what I've picked up is that typical extractors can only remove liquid water from the air, not vapor. Since your extractor is right at the compressor, a lot of the water is probably going right through it as vapor, then condensing into liquid further down the line. I've found more than one article indicating that the extractor should be at least 25 feet downstream from the compressor so that the vapor has time to condense before it gets there.

If that doesn't do the trick, there's additional equipment available. From cheapest to most expensive, you can add a desiccant dryer ($300), a membrane dryer ($700) or a refrigerated dryer ($1500+). I also saw a neat-looking product called an elliott-cycle dryer from a company called Air Options, but this is new technology and not much info seems to be available.


From contributor B:
Have your dryer as close to the gun as possible. I'm in Baltimore where it's very humid. I have mine about 10 ft. away and have no problems with moisture.

From contributor P:
Move the extractor away from the compressor as far as you can and put it as close as possible to your spray area. Check with the manufacturer for the serviceable parts on the extractor.

After the extractor you could place an inexpensive filter like the Motorguard M45 in the air line to clean up the air even more. One of those little filters that attach on the end of the spray gun will also work, but won't last as long.


From contributor A:
Another trick is to run a radiator looking zig zag line of air line down a wall next to the compressor. It acts kind of like a still and forces the water to condense long before it gets to the filter before your hose. With all that extra pipe it also acts like a bigger tank so the compressor will have less pressure drop. Make sure you put a couple of drain pipes in the zig zag section. You can find pictures of these setups in a few books.

From contributor B:
My 2 cents: Buy yourself an Arrow F-50-1 refrigerant air dryer. Best dang $1,500 I ever spent. Bone dry air on even the most humid days. No moisture at all in my finishes nor in my various (and expensive) cabinetmaking machines that use compressed air. Getting a good air dryer is one of those very good things that, once done, I wish I'd done years ago!
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