Setting Up Shop #3: Resurrecting a Dead Air Compressor

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Blog entry by DylanC posted 02-07-2011 04:29 AM 4166 reads 0 times favorited 2 comments Add to Favorites Watch
« Part 2: Three Phase Power...My Way Part 3 of Setting Up Shop series Part 4: The difference between static phase converters »

A friend of mine is a salesman for commercial-industrial air compressors and often, when he sells a new compressor to a shop, they have an older one that is being replaced. Sometimes the units being replaced actually work, so I asked him to keep an eye open for a decent compressor for my shop. One day late last fall he called me up and told me he found an older 60 gallon vertical compressor in a local shop that wanted to get rid of it. Fifty bucks later it was mine. It was a bit of a gamble, but for $50 I would at least have a good tank.

As it turns out, it had a bad pump. But 2 weeks ago my friend came through again with a spare compressor that he had laying around. It is an older model Quincy 210QRB-301 (late 1990s model) with hydraulic unloaders and full pressure lubrication. Output at 800 rpm is 5.5 SCFM, 90 psi peak pressure. The peak pressure is a bit low, but its a special purpose compressor designed for lower pressure applications. Overall, higher quality but lower capacity than the OEM pump. It would take a bit of re-plumbing, but I was pretty sure it would work.

A trip to the local home improvement store for some copper tubing, compression fittings and some other odds and ends and I was ready to get to work. First I drilled some new holes and mounted the pump. The inlet and outlet ports of my new pump were reversed from the original, so my next job was to run some 1/2” OD copper from the tank to the opposite side of the compressor. It turned out pretty well (just one slight kink), but not too bad for my first time bending copper. The final step was to run 1/4” OD tubing to the pressure switch and to the unloaders on the compressor. I tightened up the fittings, adjusted the belt tension and plugged it in (again). I was happy to see the pressure climb steadily until the pressure switch disengaged the motor at 90 psi. I’m now the proud owner of a custom Quincy compressor.

The good: A good quality 60 gallon compressor for under $100.
The bad: Low peak and average supply pressure. The maximum pressure of the compressor is 90 psi and my pressure switch has a 30 psi deadband, which means my system’s is really only to consistently deliver 60 psi air. I’ll also need to shell out a few bucks for a new motor pulley to lower the drive ratio. Right now the pump is running just a bit over its max rated speed.

A few pics for those interested:

-- Dylan C ...Seems like all ever I make is sawdust...

2 comments so far

View David175's profile


101 posts in 2710 days

#1 posted 02-07-2011 04:41 AM

looks like a pretty good deal… can get a presure switch that has a closer differential… should be able to ajust the valve unloader to get more presure

-- Dave..Pensacola Fl.........In GOD we trust

View lilredweldingrod's profile


2496 posts in 3128 days

#2 posted 02-07-2011 04:51 AM

Look at all the money saved for more clamps. lol Nice job. Works for me.

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