My Air compressor build is finally complete (Almost)

[TdK71]

I've had this old Sears compressor for the last three decades, my Dad didn't to take it with him when he moved to South Carolina so I've been using it since then and it's been very reliable but somewhat underwhelming as far some things are concerned.



So my brother and I kept an eye out on FB Marketplace and stumbled across a nice 60 gallon tank for $50. We picked it up and the it sat in the garage for a year or so until I figured out how I wanted to build it out.


Here it is in primer after I welded on the extension pad to better Mount the Harbor Freight 5hpcompressor pump.


I ran a hydrostatic test on it and it held pressure for 12 hours. This meant I could move onto the next steps in the project.


I built a bracket out of 3/16 plate, some 1 inch tube and angle iron to mount the Derale oil cooler that I'm using as an aftercooler for this project.


This is the extension that I welded onto the mounting pad so that the pump didn't overhang the centrally mounted pressure switch port and allowed me to center the entire assembly.


I bought a Vevor Motor off eBay to go with the Harbor Freight pump, and used Compressorsource.com to source the pulley for the motor and the pressure switch, as well as the new check valve for the tank. I utilized Amazon for the Derale oil cooler, and the moisture trap that I've installed between the cooler and the check valve.


This is how I ran the piping with 5/8" copper coming off the pump reduced down to 1/2" going into the cooler and 1/2" running down to the tank.


I moved it to its location yesterday and tested it out, after I ran it for 30 minutes with no load and then changed the oil. It took 4 minutes to go from 0 to 150 psi. The next step is to run my shop air piping and finish this project off so that I can get my blast cabinet setup for my restoration projects and for painting as well as air tool usage.


Overall I'm pretty happy how this is turning out so far.

 

[teknikfrog]

Very nice. Can you explain how you tested the tank?

 

[TdK71]

Very nice. Can you explain how you tested the tank?

Plugged all openings, filled with water, installed a pressure gauge and put a male pressure washer connector on the air outlet side of the tank, plugged my Pressure Washer into the fitting and hit the trigger until my desired pressure was achieved.

 

[GeoBruin]

Nice work. Compressors were like black magic to me back when I first needed one, so I bought a gently used, but still complete compressor. Knowing what I know now, I would definitely have pieced one together and would likely have wound up with a better performing overall compressor for less money.

Why did you cant the bottom of the aftercooler away from the fan shroud? I suspect it probably allows better cooling of the pump but not quite as effective cooling of the air in the cooler. I mostly ask because I struggled with the same tradeoff when I mounted mine, although I ultimately mounted it right smack against the shroud solely on the basis that others had done it that way so it was probably fine.

 

[TdK71]

Nice work. Compressors were like black magic to me back when I first needed one, so I bought a gently used, but still complete compressor. Knowing what I know now, I would definitely have pieced one together and would likely have wound up with a better performing overall compressor for less money.

Why did you cant the bottom of the aftercooler away from the fan shroud? I suspect it probably allows better cooling of the pump but not quite as effective cooling of the air in the cooler. I mostly ask because I struggled with the same tradeoff when I mounted mine, although I ultimately mounted it right smack against the shroud solely on the basis that others had done it that way so it was probably fine.

I saw a video on you tube by an old engineering guy that basically said that standing it straight up will leave water in the the condenser tubes, if you look at the tubes on the output side they are on a 45° angle so if you tilt the condenser on that angle it will drain properly.

 

[redmondjp]

You may want to lower the turnoff pressure down to 120-130psi - the pump will be much happier. I would only go to 150psi using a two-stage pump.

 

[TdK71]

You may want to lower the turnoff pressure down to 120-130psi - the pump will be much happier. I would only go to 150psi using a two-stage pump.

The pump is rated for 145psi I've got it cutting out @ 150psi I can throttle it back a bit.

 

[redmondjp]

The pump is rated for 145psi I've got it cutting out @ 150psi I can throttle it back a bit.

Just because you can, doesn't mean that you should - Compare the time it takes to go from zero to 120psi, to the time that it takes to go from 120 to 150psi. There is a very good reason why two-stage pumps were invented.

 

[TdK71]

Just because you can, doesn't mean that you should - Compare the time it takes to go from zero to 120psi, to the time that it takes to go from 120 to 150psi. There is a very good reason why two-stage pumps were invented.

Turned it down to 135psi goes from 0 to 135psi in 3minutes and 40 seconds. I'm planning on running my shop air @90psi so that should be sufficient for my application. Thanks for the advice I appreciate it.

 

[rgviewer]

Just picked up one of these yesterday, Can I ask what you used to make the connections coming off the pump into the 5/8 copper. Also is there any problems stepping down to 1/2". I would also like to put an after cooler, but was afraid of limiting or restricting the pump.

 

[The Cobbler]

nice looking . I have a v-4 Dewalt that I got on clearance missing the flywheel bolt (LH thread) . have a 60 gal tank , 5HP motor. most all the parts . just need to get it together

 

[GeoBruin]

Just picked up one of these yesterday, Can I ask what you used to make the connections coming off the pump into the 5/8 copper. Also is there any problems stepping down to 1/2". I would also like to put an after cooler, but was afraid of limiting or restricting the pump.

It will be specific to your compressor, but generally, it will be a threaded or flare fitting on one end, and a compression fitting for 5/8" copper pipe on the other. What does the outlet on your pump look like?

Can I ask why you want to use 1/2" copper?

 

[rgviewer]

It will be specific to your compressor, but generally, it will be a threaded or flare fitting on one end, and a compression fitting for 5/8" copper pipe on the other. What does the outlet on your pump look like?

Can I ask why you want to use 1/2" copper?

I have the same Harbor Freight pump that the original poster also has. I am not exactly sure what size is coming out of the pump, as to why I asked what he used, I planned on using 5/8 copper from the pump, but would also like to use an after cooler before the tank, but I see he used 1/2" and most after coolers I find use 1/2" tubbing with the aftercooler. I was worried about restricting the flow, and look for any advice to anyone who has done something similar. Thanks

 

[The Cobbler]

using 1/2 or 5/8 od will have zero noticeable effect in that situation

 

[TdK71]

Just picked up one of these yesterday, Can I ask what you used to make the connections coming off the pump into the 5/8 copper. Also is there any problems stepping down to 1/2". I would also like to put an after cooler, but was afraid of limiting or restricting the pump.

This is a very tricky connector to find, it took me almost a month to locate the right one. I got it here:
G Thread (Metric BSPP) 3/4" Female to NPT Thread 3/4" Male Pipe Fitting Adapter - Lead-Free (3/4 inch)

You can find other ones on ScAmazon but this one worked perfectly.

Oh and no problems stepping down to 1/2" from 5/8". The compressor takes 3minutes and 40 seconds to go from 0psi to 135psi.

 

[TdK71]

It will be specific to your compressor, but generally, it will be a threaded or flare fitting on one end, and a compression fitting for 5/8" copper pipe on the other. What does the outlet on your pump look like?

Can I ask why you want to use 1/2" copper?

The lines going to the Derale 15300 cooler are 1/2" AN fittings so you'll have to reduce down to connect up to it.

 

[TdK71]

I've also had to change things up a bit , because the the Harbor Freight compressor kit just isn't doing it on this compressor.
Automatic Compressor Drain Kit

I've decided to go with this instead for multiple reasons, Less plumbing and easier cleanout being two of them.
QWORK Automatic Timed Condensate Drain Valve

I think this is the better way to go on a bigger compressor, I have one of the HFT units mounted on the old Sears compressor and it works just fine for a lower PSI application, so f you have a smaller compressor I'd say use the HFT one if you can find it.

 

[GeoBruin]

I've also had to change things up a bit , because the the Harbor Freight compressor kit just isn't doing it on this compressor.
Automatic Compressor Drain Kit

I've decided to go with this instead for multiple reasons, Less plumbing and easier cleanout being two of them.
QWORK Automatic Timed Condensate Drain Valve

I think this is the better way to go on a bigger compressor, I have one of the HFT units mounted on the old Sears compressor and it works just fine for a lower PSI application, so f you have a smaller compressor I'd say use the HFT one if you can find it.

I wasn't able to get the HF auto drain to work with my compressor either. I tried two of them, and kept blowing rings. I even got an oring kit with various durometer and experimented with that and it just wasn't happening.

 

[Motofixxer]

Just picked up one of these yesterday, Can I ask what you used to make the connections coming off the pump into the 5/8 copper.

Mine seemed to be a 3/4 NPT, so anything you can adapt to will work. I used a 3/4" water heater hose copper flexible line, removed rubber washer and with some pipe dope seemed to seal right up no problem. There's a 3/4 FIP to 1/2 OD flare you can buy and use. Then it's regular 1/2" copper.