Saturday, April 15, 2006





Hello
I'm going to come off the soapbox and wander into my workshop. I really have other things supposedly more
important to do but this home project isn't without value.

Last fall my air compressor died. It was a 20 gallon, belt-driven unit with a one-piston pump and a 1hp motor. I bought it out of a surplus yard and paid 100.00 for it. This was in 1998. Of course air compressors have gone down in price.

I hated the idea of spending so much money. I also had a 13 gallon air brake tank someone gave my dad for use as an air tank. This translated into trips to the gas station for air as it leaked slowly. I dreamed for years of having an air compressor to inflate tires and perhaps operate air sprayers and other tools.

For 50.00 I could get an air pump and motor off Ebay. So all I had to do is buy a regulator and the framework and piping would not cost much. So I thought. I sanded the tank and flushed trash from it. Paint remover and a RotoZip's sander attachment took most of the tank down to bare metal. I had to use Liquid Wrench and elbow grease to pull out the plugs inserted over 30 years ago.

My secret to painting it was to hang it like an animal being skinned. I painted the tank with primer and two coats of paint. I painted it red since I had that color available. I had fixed the PowerPainter so I was in good shape for doing this quickly.

I almost had the compressor ready when I found a leak in the gasket of the pump. I was dumb enough to pull the piston out of the channel rather than remove the arm from the rocker. Thus I ruined the piston gasket. By this time I decided on either a new compressor or a belt-driven pump.

I saw several candidates for the pump on Ebay but they were either too costly or required a 5hp motor. New compressors ran 130.00 for units that would run my paint sprayer (yes I know about the Power Painter; I already had a spray gun). So I referred back to a Mother Earth News article from 1978 that the magazine graciously archived on their web site. I also read some web sites about off-road vehicle air compressors tethered to the drive belts on off-road trucks.

The heart of these units is a York vehicle air conditioner compressor. Ford and Chrysler used these in the Sixties and Seventies for vehicle air conditioners. Gas- be it air or Freon- must be compressed to achieve its function. In air conditioners it is to create a cool coil for a fan to blow cool air. I found a York-type compressor from a late-Sixties model Mustang on Ebay. It was from somebody in Georgia so shipping wasn't too hideously expensive.

There are two caveats to using such units. One is to have the clutch engaged at all times. Off-roaders have electrical connnections engage the clutch as if the air conditioning compressor were still compressing refrigerant. Another issue, especially important for painters, concerns lubrication. You can fill the compressor with 30W oil up to the shaft but some oil will emerge from the discharge.

I dealt with the clutch first. The clutch would have to be welded onto the pulley. With cast iron this is easier said than done. My machinist, a customer at my store, proposed another idea. He had milling equipment to take the lip of the shaft on the clutch assembly down to where no air gap existed between pulley and shaft. Visualize this; the clutch assembly has a shaft onto which the pulley slides and engages if there is electrical activity to grab the shaft. This slides onto a beveled shaft running the pistons on the compressor.

This wouldn't happen because the electrical connectors on the clutch were gone. So the machinist lathed the lip down to where tightening the clutch shaft onto the beveled inner shaft would eliminate movement. He said for me to try it out.

I went home that night and tried it. Voila! I turned the pulley and air came out. I had to modify my frame to hold the belt-driven assembly. The previous pump was a small motor and piston that lay at a slant. So I had to rebuild the frame. I had to drill- using a 1966 vintage drill- some large holes in an axle holders I fashioned. I need to make a few minor adjustments, find the axle I lost in the shop, and put the motor and compressor
mounts onto the unit before the frame is complete.

For my next trick I put one more coat of paint on the tank/frame assembly. There is a Square-D pressure switch I had left over from the previous completion of the task. It is still connected and plumbed. I have the regulator on the rear of the tank. The compressor will go on the front and the motor goes on the rear.

To be continued.