Compressor Oil Leak

Tips for keeping oil in the hose, caused by a compressor problem, from contaminating guns and finishes. July 24, 2005

Question
I have a sixty gallon porter cable Devilbiss compressor that suddenly started blowing oil out the air hose while blowing dust off of some stock. I have a new ring kit, valve kit, and gasket kit on order (hopefully it’s one of these, as I could see nothing wrong when I tore it down). How do I get the oil out of the tank, filters, hose, etc.? I spray water bourne and am nervous of contamination. Any help is appreciated.

Forum Responses
(Finishing Forum)
From contributor D:
I would suggest letting the compressor build up in pressure several times and then release it trying to blow as much oil through the lines as possible. Then I would place an inline water/oil filter and replace the hose from the filter to the gun. It will be a lot cheaper than fighting with the possible contaminated pieces you finish.

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From contributor R:
I had a Grainger sixty gallon that started letting a little oil pass through - never so much that I saw it coming out the air gun. I found that my air and oil filters, plus a desiccant dryer stopped any contaminants from getting to my spray gun.

Contributor D has the right idea, though. Fill and bleed the compressor tank several times and replace any flexible lines that go to your gun. Air and oil filters are a must, and if you don't have a refrigerated dryer, the desiccant dryer works well for me.

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From the original questioner:
That’s pretty much what I thought I would do, and just wanted that second opinion. I am considering getting a second sixty gallon unit to alternate with to help keep the first unit cool (less condensation) and have as a back up. I am a cabinet maker and only finish my own work, so finishing is a lesser part of what I do.

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From contributor S:
There is no real good way to remove all the oil from your lines. What you need to do is put a coalescing filter down-line from your compressor. Depending on the make (Devilbiss, Graco, Sharpe), they will remove contaminates down to 0.01 microns. This will get rid of nearly all the oil.

Of course though, the best suggestion is a 3 stage desiccant system. The first stage is a water trap (mostly around 1-5 microns), the second is the coalescor (0.1-0.01 microns), and the last stage is a chemical desiccant system. They are a bead that absorbs the moisture. That would be the best way to go.