I humbly started my love affair with compressed air a few years ago when my wife gave me the ultimate Christmas present. A Sears oil-less air compressor. I vividly recall my emotions that day. I felt like I just passed the fastest guy on the track. I'm a contender and I ain't lookin' back.
Almost immediately, spare waking moments were spent learning about compressed O2 and the tools it powered. I also learned that a compressor holds a great deal social value. At a party, when conversation slows, I worked in a mention of the latest task I performed under air-power. They hung on my every word. Sure you could use electric tools but air power, now that's manly!
Early on, the compressor did all it was asked. The small displacement piston with short stroke and high RPM, made a deafening noise while it crawled its way to 125 psi. The 30-gallon tank looked big but plug in a high-speed cut-off tool and work time is limited to 15-second bursts between pressure build up. Not much capacity but it's tolerable.
Then catastrophe hit one weekend. Now I've painted several bike projects without incidence. But this time it was big project. Repainting the BMW R100 RS fairings with multiple coats of white, blue pearl and clear coat. As it turns out, the spraying produced a good amount of paint dust and the compressor was in the garage with the project. About 90% into the project, the minimal air filtering (fine enough to keep Raccoons from moving in) allowed the piston to ingest enough dust to seize. Its final death throw was subtle. The RPM increased and the earsplitting noise went down with the pressure. I had to borrow a compressor and finish the next day.
Undaunted, parts were acquired and the compressor unit rebuilt. Something wasn't quite right because at first turn-on the noise was 3 times worse than before. I counseled with a so-called technician and not able to find the problem, he thought it should bed-in, I let it go. After several hours of brain rattling, eye squinting noise, it died again. This time before departure from this world, the unit balked and missed. The entire 150-pound unit shook and shuddered like a mechanical Ricky Martin dancing the Macarena. At the end, the rod broke and sent shrapnel to ricochet off the floor.
I'd had enough with wimpy, noisy, oil-less compressors. With what was left of my hearing, I set out to find the last compressor I would own. I settled on a 2 stage, inter-cooled, 175 psi, belt driven, 60-gallon tank, 240volt, stand-up Ingersoll-Rand unit. These people have been squeezing for a long time and this bad boy has a compressor on top that looks like a '70s Ducati V-Twin. When it runs, it chuffs like a four stroke and when the pressure reaches cut-off, the relief sends out a hefty sigh of relief to let you know it's ready for work.
Now that I've got plenty of air, I needed to get it plumbed right. My intuition got me going but I had to know more. I had to tame the full power of 175-psi and get it moved to the right places in the garage. I realized the only solution was to get to a deep source of knowledge and wisdom. Meet with the Sage of the Shop, the Master of Milling, the Lord of the Lathe; Dr. Strangemotor, otherwise know as Daryl Bane. Because if the subject turns to bike restoration or shop machinery, an audience with the Doctor, is like an audience with the Dali Lama.
I was a bit intimidated when I walked through His shop door. For a moment I wondered if I would be met by a lackey informing me that the Doctor was too busy and I'd have to return another day. But it wasn't that way at all. The good Doctor emerged from the back of His pristine shop with a polished spanner in His hand. I was in awe.
He had me sit in front of him on a futon gently resting on a thick rug of exotic origin. He was perched on a mini-throne, wrapped in a shawl of worn but clean, soft shop rags. With legs crossed yoga style, His beaming smile put me at ease We talked about many shop things. The powerful metal cutters and sheet steel forming machines, the spray booth with its exotic filtration system. Everything.
Then I asked about air and He began a dissertation that made me glad to be an engineer. He pointed to the walls and piping overhead. There it was, beautiful polished 1 inch copper airlines. All the joints were perfect. No lead drips, only shinny fillets of just the right contour. He explained the necessity of sloping the lines for condensate drainage; judiciously placed ball valves for quick turn-on and off of airflow; He explained the drying / regulating system. Then He took me outside where the giant horizontal 2-stage compressor lived. Lying there on the concrete slab, like a Grizzly bear in hibernation, waiting to wake up when the line pressure dropped.
Too soon my time with the Doctor was exhausted. My head was full of Bernoulli's principle, flow charts and pressure vessels. I humbly left the shop, a wiser man about compressed air.
What happened to the old Red tanker? I rebuilt it again. I used the same procedure and care but this time I added a little Dr. Strangemotor mo-jo chant to excise any demons before turn-on. It worked, and now lives happily in my son Chris's garage. It's still as obnoxious as a Liberal Democrat, but like them, its only job is to pass air and it does that just fine.
Want to know more about compressed air? Check out the Sharpe Manufacturing Company web site for excellent information about compressed air systems and shop air piping layouts. http://www.sharpe1.com/dr-pipe.htm
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Revised: January 29, 2008 .