My firm has a 6 bay garage behind our main building. It used to house a car mechanic. I went out and poked around and found some old 1/2" galvanized piping that was used for supplying air to all the repair bays. I like to be as green as I can be at work and in life... I am also always on the lookout to save money if at all possible, so I asked if I could salvage the old pipe. My boss said I could have it if I was willing to do the work to remove it. In all I removed about 40' of piping and a handful of elbows, a "T" connector and a union.
I saw this diagram referenced on a few other websites http://www.tptools.com/StaticText/airline-piping-diagram.pdf and followed the concepts. I installed a 6" riser at the tool end and sloped the main pipe back toward the compressor. At the compressor, I upgraded the connection at the ball valve from a 1/4" nipple and adapter bushings to a larger 3/8" nipple. Then I ran a 3/8" lead-in hose line (from Harbor Freight) to a 1/2"-3/8" adapter bushing. I installed a union where the hose connects to the hard line so I can break everything apart from that point without having to mess with twisting up the hose. At the other end of the line I installed a 6" riser on a "T" connector out to the dryer/regulator. On the bottom of the "T" I installed a 6" nipple and a drain cock at the bottom. All of this added together should force the water in the line back toward the compressor, or at the least, it should drain into the 6" drain at the bottom of the "T" connector.
My father came over and helped me assemble the piping in the driveway, then we put a few mineracs on the wall and clipped the piping in place. After the piping was up, I connected the union and the lead-in hose from the tank.
I wound up purchasing just a few items: the drain cock, yellow (gas) tape, a bushing, 2 elbows and 4 nipples 5" long. I needed 1 piece of pipe cut and threaded. The man in the plumbing dept at Lowes was nice enough to do it for free since I had a handful of other plumbing supplies.
I tested the system out tonight with about 90 minutes of constant grinding. I saw some water about an hour and 20 minutes into the operation. The compressor ran almost the whole time. Once I drained out the dryer and drain cock the air was totally dry again. With my old setup the water would show up in about 20-30 minutes. I suspect if I drain the cocks every hour or so I should be dry all the time. I could also probably use a new dryer as mine is 15 years old and just a cheapo craftsman. A Sata or other paint-specific dryer would probably be much better.
I test fit the headlight bucket to see how much grinding/bodywork I could do on the back side of the headlight area AFTER I get the bucket installed