Piecing together an air compressor

[70-K5]

I've gone back on forth between buying an old compressor like a Quincy QT54 and rebuilding it or buying a new one.

Thing is, I have a 2hp motor I bought a long time ago, 1750 rpm, continuous duty nema 145t mounting pattern 7/8" keyed shaft 110/230v.

I found a bare 80 gallon horizontal tank for under a hundred bucks, but then I question my pump.

Harbor freight has 3hp and 5hp air pumps, I know HF is hit or miss, but my thought is a pump running below the rated speed should have a good chance of surviving.

I dont have a lot of air demands, the biggest would be running a medium sized blast cabinet for short periods, cleaning a single 15" wheel for instance.

Am I barking up the wrong tree or would a 3 hp pump with a 2hp motor work with an 80 gallon tank? I'd be in it about $300.

 

[joe_padavano]

You're going to be very dissatisfied with that setup for running a blast cabinet. Get the highest SCFM pump you can afford and select the correctly-sized motor to run it. The siphon blast gun in your blast cabinet will be constantly "chugging" due to insufficient pressure, and you'll spend more time waiting for the compressor to pump back up than you will be blasting.

 

[930dreamer]

Though it can be done with a smaller compressor, a true 5hp compressor (15-20 cfm)would be the smallest compressor with good results.

 

[56Safari]

My 80 gallon 5HP Campbell Hausfeld compressor runs continuously when blasting, it does about 15.1 scfm @ 90 psi... I wouldn’t get anything smaller


Sent from my iPhone using The Garage Journal mobile app

 

[dirtydogintex]

I've gone back on forth between buying an old compressor like a Quincy QT54 and rebuilding it or buying a new one.

Thing is, I have a 2hp motor I bought a long time ago, 1750 rpm, continuous duty nema 145t mounting pattern 7/8" keyed shaft 110/230v.

I found a bare 80 gallon horizontal tank for under a hundred bucks, but then I question my pump.

Harbor freight has 3hp and 5hp air pumps, I know HF is hit or miss, but my thought is a pump running below the rated speed should have a good chance of surviving.

I dont have a lot of air demands, the biggest would be running a medium sized blast cabinet for short periods, cleaning a single 15" wheel for instance.

Am I barking up the wrong tree or would a 3 hp pump with a 2hp motor work with an 80 gallon tank? I'd be in it about $300.

Thar rig would be undersized for your purposes although it might work at it in a pinch.

Regardless make sure your old/new tank is an ASME code tank. There will be a small metal plate tack welded to the tank giving info like mfg, mfg date, press@temp...
If you use an old tank you prolly need to have it tested/inspected to keep from charging a bomb.

 

[txvwnut]

That 2hp motor will not run either of the pumps the OP listed. If you are going to use a 3hp pump you need a 3hp motor to run it, a smaller motor will struggle to turn a pump that requires more hp.

 

[70-K5]

Thanks for all the input guys.

Looking more at my options I'll just have to wait for the right compressor to come up.


There is an oil less compressor cheap, it has a bad pump.. But has 60 gallon tank and a 5hp motor. Motor is 240 22 amp. ProAir II?

Anyone know if it is safe to mount a new plate up top and use that motor with one of the previously mentioned HF pumps?

 

[930dreamer]

Yes you can mount a different base plate but not welded.

 

[joe_padavano]

Thanks for all the input guys.

Looking more at my options I'll just have to wait for the right compressor to come up.

Keep an eye out for three phase industrial compressors of 5HP or more. Since they are three phase, then tend to sell for a lot less than comparably sized single phase. Buy an appropriately sized single phase motor and you're good to go. I did this with a 7.5 HP/23.5 SCFM compressor and I have about $800 into it, and most of that was for a brand new Baldor motor. If you can find a 5HP compressor, single phase motors are considerably less expensive. The beauty of my setup is that not only does the compressor easily keep up with blasting, I was able to switch to a larger nozzle for faster blasting.