I've never owned a large air compressor before

[bofh]

I could buy a nice 30 gallon air compressor or maybe I can come up with the cash for a 60 or 80 gallon version of the same compressor. A bigger tank means I can push more CFM for longer which is great.

But here's my question-- are there any downsides to a larger tank? One thing I'm concerned about is starting the compressor after it's been dormant for a long time-- does a larger tank take much more time to get air pressure at the hose?

I have two use cases in mind: One: I'm going to spend a long weekend with a pneumatic polisher. Obviously the bigger compressor is better for this. Second use case: The compressor has been off for a month, the tank is empty, and I just realized I need to top off air in my car tires (or even bicycle tires). Today, my little pancake compressor is good to go in about a minute for this-- what is a monster 80 gallon 5hp compressor going to be like in this case?

[ducksfan]

They are different compressors, for different uses (60/80 gallon; pancake). You need both if you're going to have a large compressor for occasional use.

The downsides to a large compressor are cost, size (They are a beast. Good luck trying to move one even with help.), the space they take up, and if your not a business, probably a lot of feeling like you didn't need something that big. Oh, and also you need special wiring for it.

Many times I have thought, it would be better to have two thirties.

Northern Tool has Quincy's that are 30 gallon and put out 7.4 CFM @ 100 PSi with a top pressure of 135 PSI. Not to shabby. I doubt if they have Baldor motors. But the Quincy compressor has a great rep. If the motor ever went out, it's probably a standard frame size. A Baldor should be easy to swap out.

[bofh]

The footprint of a 30 gallon is about the same as an 80 gallon. Why would you get two 30's?

[dgage]

As someone who has a 30 gal compressor, if you think you need a bigger compressor, you do. I’d recommend getting the 80 gal, which I’d say generally are built better and with longer duty cycles (run longer between breaks). And if you need something small, I’d get a small 1-4 gal California Air Tools compressor as they are VERY quiet and easy to move around. I’ve had the C.A.T. 1 gal compresser for 1.5 years and it is much lighter and way quieter than the PC pancake it replaced. As far as the 80 gal I’d probably look into a Quincy if buying new.

[ducksfan]

Look at what I added to my post. For most jobs that compressor would be enough.

A thirty is just so much easier to deal with. And you have to have two compressors anyhow if you have a large one.

[ducksfan]

Maybe it's just me. I would rather have a 30 hung on the wall and a lowboy (or even a small portable) underneath it.

It's not like in years past where single stage compressors only went to 110-120PSi. Most now will go to the 130's. And also, today's tools typically use less air.

It depends what you need. For me, I mostly need steady air at 90 PSI. 7.4 @ 100psi would do that with extra from a second source when I rarely need it.

Now, if you're painting and cooler air is important ...

[ducksfan]

Ha! I just noticed, the Quincy's are 24 gallon, not 30.

The thing to check is the duty cycle on the motor and compressor. A tech at Northern should be able to answer that. Or, just call Quincy.

[MIsnowman]

Go with the bigger compressor and make sure you don’t have any leaks. No need for a second smaller compressor then. I have a 60 gallon Quincy 2-stage compressor in my shop and it sits for long periods of time and it never has less than 100 psi in the tank. That’s more than enough pressure to air up any car/truck tire. With the larger tank I usually don’t even turn the compressor on if I’m just topping off a tire.

[2black1s]

While larger tank size does provide some benefits, i.e., cooler air, large volumes for multiple users (like in a body shop), initial fill time and recovery time is definitely longer.

I've had a high performing 30 gallon single stage compressor since the 1980s that I've used for everything from running air tools (sanders, grinders, etc.,) to painting cars. Max pressure of 135 psig with CFM ratings of 8.1 @ 125, 9.0 @ 100, 9.3 @ 90 & 11.3 @ 40.

About the only operation I did where I could have used more air is sandblasting for long periods. Then I would piggyback another smaller compressor inline to provide additional air.

I also have my 30 gallon compressor piped through an old air conditioning condensor to cool the air before passing through the filters.

The bottom line in my eyes is the compressor head unit output. Regardless of tank size the compressor needs to have a high enough output for the tasks you plan to use it for. I've seen "homeowner" class air compressors on the market today with 60 & 80 gallon tanks that actually have lower CFM ratings than my current 30 gallon compressor.

CFM and Pressure ratings are the specs I'd be looking at. Tank size and HP ratings, in many cases, are nothing more than marketing hype.

[dgage]

That’s a good point 2black1a but I’m not sure they make such a 30 gal anymore. I’ve only ever seen less expensive ones. I’m assuming the motor you have is 220V to have that much capability and I don’t know that I’’ve seen a 30gal like that. Then again, when looking at 220V, I shift to 60/80-gal because those are most prevalent.