Water passing through the air filter

by Wayne Osborne
(Barrie, Ontario, Canada)

I am a hobbyist and use a Bostitch 6 gallon pancake air compressor for my airbrushes. I was using only an inline desiccant filter at the airbrush and was getting water in my paint and had to replace the desiccant beads every 2 to 3 weeks. I recently added a small 1/4" air filter at the air compressor assuming that this would cure my issues, but I was wrong. I continue to use the inline desiccant filter at the airbrush and my hose length is 25 feet, but, the desiccant beads are still only lasting 2 weeks and I am not seeing any water being filtered. The filter element is a 5 micron rated filter.

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Jan 21, 2016
Water passing through filter
by: Bill

What I think is happening Wayne is that your compressed air has a high water vapour content. Since that water is not in liquid form a typical general purpose compressed air filter won't remove much of, or in your case, any of that vapour.

Your air line is becoming the after air cooler. As the air cools, it condenses the vapour into free water in the air line, flooding your desiccant dryer.

Try putting the compressed air filter on a wall mount at the working end of the air line, then take air feed from the filter, in a shorter air line, into the desiccant dryer at your paint spray gun.

If that doesn't dry the air enough, then it's time for a bigger desiccant dryer.

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