# Air Compressor Project



## Tinker2 (Sep 3, 2019)

I recently purchased a used SpeedAire ‘Cast Iron Series’ air compressor off the local CL, for a decent price. It is a 5 HP, 2 Stage, 240 volt, with an 80 gallon tank, and a magnetic switch. It was in good condition visually and ran well. It appears to be in original configuration. Upon returning home with it, I only intended to scrub it with a little degreaser to clean it up a bit and then put it into service. However, to my surprise, the industrial strength degreaser that I had on hand, acted like paint remover instead, and bubbled a large area of paint off the side of the tank. There was no indication that the compressor/tank had come from the manufacturer with anything but a single color coat. There was no evidence of a primer coat under the color coat.

I ended up having my local industrial paint supplier color match the green paint. I removed the motor, mag switch, and belt cage. The pump was masked off, as were the original decals on the tank. The tank and mounting plate was sanded and scuffed, then primed and painted with an epoxy primer sealer, and several color coats of single stage urethane paint. The belt/pulley cage was sandblasted, primed and painted black.

I replaced the non-on/off pressure switch with a new one that did have on/off switching capability. I also replaced the tank pressure gauge and I welded a flat plate to the back side of the mag switch frame, to mount the line regulator and filter on. I also built a dolly to mount the compressor on. The dolly is built from 2 in. square, x .125 in. wall steel tube, and painted gloss black. The oil was drained and replaced with a synthetic compressor oil, and a new air filter element was installed. The few galvanized pipe fittings were replaced with brass fittings and new hoses were also installed.

I was curious as to the condition of the pump. I did not get a manual with this but from researching online, I believe this pump is rated at 17.1 ‘Delivery CFM’ at 175 psi, to 18.5 ‘Delivery CFM' at 100 psi.

I located an online ‘Compressed Air Flow Calculator’ for determining air flow [CFM] in to or out of a tank at http://www.egnergy.com/calculator.html .  There is also a calculator for determining ‘Air Pressure at Altitude’ at https://www.mide.com/pages/air-pressure-at-altitude-calculator , should you want to plug that information into the CFM calculator.

I’ve set the compressor cut out pressure to 125 PSI and conducted several timed tests from 0 tank pressure to 125 psi. Using the mentioned calculators, this compressor is operating at 20-21 PSI. I am happy with that.

The next part of this project will be an air dryer from copper tubing.

Some before and after photos-


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## westerner (Sep 3, 2019)

Very Nice!
	

		
			
		

		
	



	

		
			
		

		
	
Here is mine, from 1948. First owner was the gas station where the kid (my cousin) would check your oil and wash your windows while he pumped your gas. Tank was drained EVERY DAY, or you found other work!

It has finally rusted thru, at 71 years of age. The motor you see under the full size WD-40 can had a tag that called it a 2 hp motor!
Belgians, or Clydesdales no doubt. Certainly not the Chinese ponys listed on the tag today. 

I am piecing together its replacement, but it aint gonna be the same.


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## Ulma Doctor (Sep 3, 2019)

Nice work!
i worked on my share of speedair compressors, but never repainted one or made it look nice.
we had one exactly like you have here for the shop air about 20 years ago.
they are good compressors.
you'll have plenty of air to run most anything you need to.


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## Tinker2 (Sep 6, 2019)

I appreciate the comments and thumbs up. Thank you.


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## Janderso (Sep 20, 2019)

Isn’t it amazing how long these pumps run.
1948, that’s incredible.
I recently replaced the compressors at work. We run two shops with 4 techs in each shop plus a detail dept.
They run from 6:30 to 5:00 five days a week. For decades!
We change the oil every year and replace or clean the air filters.
Ingersol Rand 8 hp pumps, pretty fast recovery. I don’t know all the specs but they have coolers and weren’t cheap.
One of the ones replaced was there when I started in 1986. It started sounding like the African Queen about ten years ago.


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