On Friday, March 16, 2018 at 2:38:34 PM UTC-7, Tony wrote:
One of our club members fabricated a nifty water quencher. He had a coil of copper tubing made that fit nicely in the bottom of a 5 gallon bucket. Compressed air was routed through this tubing, which sat in the 5 gallon bucket, buried in ICE. At the end of the copper tube was a big water trap and then the line going to the paint gun. All that hot humid air coming out of the air compressor was cooled down, any moisture condensed and then trapped.. We also put an inline trap at the gun. Same philosophy as the refrigerator water trap mentioned.

Stewart Systems does not recommend Turbine systems, this was tested and found to be true by another club member. It is also a water borne paint system, and as such is incredibly sensitive to moisture in the line. We have learned that the hard way on the three gliders (So far) that i've been involved in refinishing with the system.

A refrigerated air dryer will cool the air to about 40 F, lowering the dew point to at least that by condensing the moisture out. The air is then passed through the condenser, elevating it back to room temp or so, now relative humidity will be quite low. The bucket of ice will do the same thing (for awhile) but you want keep from having a low spot in the coil of tube, a bit of a problem to work out. The reason is that water will condense and puddle in the low point at low air flow, they blow through in a slug when air flow increases. This is the same reason you want the air lines overhead, rather than under the floor. I've had to abandon the air lines under the floor of my shop for this reason.

If you look for a little while, you can get a refrigerated air dryer on ebay for about $200.