Air Compressor Choice for Small Shop

[Braymond141]

I'm conflicted with choosing the right compressor for my small shop. I currently have a Harbor Freight two-stage 60gallon (15.8cfm) that cannot keep up with my new blast cabinet. It's also way too loud. Here are my requirements and setup;

•Must be quiet (I do have a "compressor" closet to stuff it in).
•Must keep up with my VaporHone cabinet at 90psi with no drop while in use.
•20cfm minimum I think, I'm not sure.
•No bigger than 80-gallon.
•Shop has 3-phase if needed.
•Under $3k.

Do I stick with a traditional piston based setup with silent air filter setups, or do I just go scroll? I have the option use the 60-gallon HF tank for air storage if I go scroll since I can't afford most all-in-one set that meet my cfm requirements.

Piston compressor setups I have no idea what to choose as I'm sick of listening to them. Open to being proven wrong they can be tolerable. Scroll side I have considered two QST 30/60 Eastwoods or an Amazon HPDMC 7.5HP Spin-on Oil Separator Rotary Screw Air Compressor 29cfm@125PSI (can't post links yet)

Help me pick the right compressor. I'm stuck and don't want to redo this purchase.

Thank you.

 

[cashishift]

FIAC sure are sweet - but they aren't cheap.. AT ALL.

Will it be heated all the time?

 

[BillK]

•20cfm minimum I think, I'm not sure.

Until you are sure nobody can really answer this question properly.

 

[Augus7us]

Since this is a small shop, do you have the power to run a 7.5HP unit?

 

[Dan in Pasadena]

Would seem so:

....
•Shop has 3-phase if needed.

Since this is a small shop, do you have the power to run a 7.5HP unit?

 

[Braymond141]

FIAC sure are sweet - but they aren't cheap.. AT ALL.

Will it be heated all the time?

or powerful AT ALL.

Really cool, but not adequate. I'd like to be around 25cfm if possible.

 

[karoc]

Like the old saying get the best that you can and add few hundred to it. But also airlines is just as important, I would say that if it was me and it will be in year or so is to run pipe over to your sandblaster and not use a 1/4 air hose. Even if you have 20cfm compressor you need the airlines to deliver it. There are some big name brands out there but they were out of my budget so I had to settle for something cheaper. But keep in mind this is a tool that you put in corner and forget about but you want it to work each and every day for rest of your life so if possible try get the best.

 

[matt_i]

Bottom line is if you need more airflow, you need more Horsepower.

Pressure * Flow = Power*, so if you need more flow keeping pressure constant, you need more power. The suggestion above to use a 7.5hp motor is an excellent one.

I looked at the Eastwood QST and it seems very quiet. Impressive. Not sure about its longevity though...if that were the sweet spot in price, performance, and longevity, wouldn't all the "big names" be doing that by now (??)


* Using English units of (lb/in^2) * (in^3/sec) boils down to in-lb/sec just as a gut check here...

 

[sz0k30]

A buddy has a good size blast cabinet - (I don't know specs). Had a 5HP 60 gal compressor that would not keep up with it. Got an IR 7.5HP 80 gal compressor that has no problem keeping up.

 

[mcf12]

Braymond, thanks for this thread. On a similar journey. Upgrading from 2 HP ingersoll RAND piston. Same issues, but not running blast cabinet. Are you keeping inside or outside shed?

 

[nadogail]

Pperhaps you might find a previously owned compresser that will meet both your air requirements and budger.

 

[Hack Fabrication]

I've got a 7.5hp IR with 80 gallon tank. It will put out 24.3 cfm @ 90 psi. 24 cfm at max pressure.

I have an Econ-O-Blast cabinet:

The cabinet has a 24 cfm gun, so the compressor does work fine for blasting, although during long blasting sessions, it will cycle continuously. I could eliminate some of the cycling by going to a smaller gun. But haven't.

If I had some additional air storage, it might eliminate some (but not all) of the cycling. The only answer is more cfm. Or in my case, I might try a smaller gun.

 

[sberry]

Used 3 phase are quite common, would take a look at that and put a shroud around to knock some sound down.

 

[Dan in Pasadena]

If 24 cfm ain't enough for anyone's garage, well then sheesh!

 

[strutaeng]

Yeah, for media blasting, a 7.5 HP is like bare minimum, and that's with a small-ish nozzle on a cabinet:

https://www.milessupply.com/2018/02/20/chart-compressed-sandblasting-stone/

The guys doing those auto stripping job on-site are using large nozzles and those diesel tow-behind compressors.

I don't think there anything out there that will meet ALL of the requirements the OP is looking for.

 

[nadogail]

IMHO, life is a series of compromises between what you would like to have and what you can afford. Sometimes we bite the bullet and find a spot in the midst of those points.

 

[FTG-05]

Under $3k, 10 hp, 3 ph:

https://eatoncompressor.com/product/10hp-air-compressor-single-phase-v4-80-gallon-vertical/

 

[sberry]

If he has 3 can probably tolerate a 10 motor. If media blast is a real concern which it might be if he is setting up for it then the extra cost to have good air or as much is needed is worth the DIFFERENCE in price. Media is slow, its expensive, its tedious and the faster its done the more the comp is OFF and would size it to run continuous with blasting Would run the pump till I was done.
The mechanics tools might not cycle it so often, will recover fast and be OFF. I see some blast on a couple tv shows and it kind of looks like they accepted the speed but it wouldnt take me long behind the hood to be figuring how as to speed it up.

 

[sberry]

As was eluded to by another guy,,, size matters, can set up 2 stage which saves sand.

The cabinet has a 24 cfm gun, so the compressor does work fine for blasting, although during long blasting sessions, it will cycle continuously. I could eliminate some of the cycling by going to a smaller gun. But haven't.

If I had some additional air storage, it might eliminate some (but not all) of the cycling. The only answer is more cfm. Or in my case, I might try a smaller gun.

What do you mean by cycle continuously? For long sessions I want it to run continuous and get as much as I can, bigger gun if it is shutting it off. Bigger tanks is for when you want more air than the pump can deliver. I wonder if and how much less heat a 2 stage is making pumping at 100#

 

[sberry]

Big tank is so the pump can be charging while the tool is off, its for storing energy, like a battery on the line. For blast there is not a lot of point in compressing it beyond the demand, open it up till its running at the pressure at the nozzle. When you shu it off it wil go to full and shut offm when yoiu resume it will be at kick on with the system pressure low, keep it low by running all it can.
Same for our water, when I water the lawn run all the sprinks I can below cut off, leaves system pressure strong and able to handle incidental demands.
I got one I use now, if it was more frequent would re plumb just a little to gain a little more so when I want it continuous it would cause some system pressure drop so its more efficient. I open another up some especially at night filling a pond, can live with lower pressure if not so many using it. A few, 10# over cut in or so that there is a little headroom for incidental demand.
Reason I even consider this is that it makes it out loud so to speak and I can change the cost some.
One well filling has no restriction, so much cheaper to pump. I added a second line, kind of a loop to one but didnt need to use it. Was going to see whjat the demand difference was????
Back to the blaster. When not cycling use a bit larger hose, you can drain a 7.5 with a 3/8 but there are some loses. 1/2 to that unit. 20cfm,,, 5 hp, its a minimum, but if I was goona become intimate with it 7.5 might run steady and at 10 would probably need gun parts changes. If it was making 90 or 100 with 5 its probably sufficient in some sense.

 

[sberry]

I am curious when the guy above said,,, 5 wouldnt keep up? Does that mean the pressure dropped below the work or that it run continuous?
No point in compressing it any higher than it needs to do the work in the case of sandblast. I have had portable sized wrong and cycled, if it was mine and had to use it steady would have improved it a bit.

 

[sberry]

I would be testing a little and watching the gauge and see where it was hitting hard enough at. Open it up till the system pressure was a bit above the regulator, size the jet. Pressure pot might need nozzle change.

 

[fuelie74]

I run a 1972 Champion that I got used and replaced the motor. If the time ever comes to replace it I will buy another Champion.

As far as requirements to me you want a two stage pump and it needs to be a low rpm pump. The cheaper units speed them up to get more CFM, all that does is make them obnoxious and create moisture.

Sent from my SM-N960U using Tapatalk

 

[Hack Fabrication]

As was eluded to by another guy,,, size matters, can set up 2 stage which saves sand.

What do you mean by cycle continuously? For long sessions I want it to run continuous and get as much as I can, bigger gun if it is shutting it off.

I've got to agree with you on that. My compressor will run almost continuously during those long sessions. But the 24 cfm gun still doesn't lose efficiency.

I do need to replace the media (it's probably close to 20 years old), as it's beginning to degrade a bit.

 

[Braymond141]

I think I've come around to a piston compressor being usable. The Emax 7.5HP Silent Air looks to check all the boxes.

They offer both single phase and 3 phase. 31cfm @100psi. $3200
emaxcompressor.com/products/emax-industrial-plus-7-5hp-80-gallon-3-ph-silent-air-system/

Does anyone have a better option with the Silent Air setup?

 

[Braymond141]

If 24 cfm ain't enough for anyone's garage, well then sheesh!

It's technically a commercial space with a 28x45 shop floor. I do private work and also a lot of my own. The compressor is just for the Vaporhone.