View Full Version : Which compressor: 60 or 80 gallon?


bmwpower
01-23-2006, 09:40 AM
With my new garage almost complete and my old compressor acting up, I'm looking for a new unit.

Let's say you have 2 compressor - one is 60 gallon and the other is 80 gallon. Both have similar specs for CFM, etc., but the 80 gallon is considerably bigger and a bit more money. I don't want to limit my capabilities as I might end up using a blast cabinet or paint gun sometime down the road.

The questions is, if floor space is a big concern (and money too), what advantage should an 80 gallon have over a 60 gallon compressor with similar specs? I read Jim's explanation supplementing the air output, but I'm not sure I completely follow. I guess I need some numbers and calculations laid out for me.

Let say, for example both units put out 20 CFM @ 90psi.
If I start pulling more than 20CFM, the tank reserve helps me keep up with the tools. But to what extent? And how much more for an 80 gallon? 33%? (80 - 60 = 20, 20/60 = 33%)

Uncle Buck
01-23-2006, 09:57 AM
In a one man shop I doubt the difference would ever be enough for you to notice. If there were multiple parties using the same compressor at the same time it could make a huge difference, but how many air tools can one guy use at the same time?

REFLEXX
01-23-2006, 10:01 AM
Only one advantage with my 80 gallon: time between cycles. Unless you're an auto body shop with five guys using air sanders at the same time, you will not see a big difference.

I have a CNC mill that makes my 80 gallon cycle every 6 minutes!!! A 60 gallon might have to do that ever four, so for me it's worth it. Without the CNC running the air compressor goes off maybe 3-5 times a DAY.

Just make sure you buy a unit that's 100% duty cycle (can run consistantly) and you'll have no issues keeping up with any tools / blasters / machinery.

my 2.5c

bmwpower
01-23-2006, 10:01 AM
In a one man shop I doubt the difference would ever be enough for you to notice. If there were multiple parties using the same compressor at the same time it could make a huge difference, but how many air tools can one guy use at the same time?


I know. It will be mostly me, but my buddy might be using the air occassionally when I'm using the air as well. 80 gallon tanks are BIG and I'd like to stick with a 60 if at all possible.

kartracer55
01-23-2006, 03:44 PM
Youll have no problem... There have been times when the air ratchet and the thundergun were running at the same time and there was NO loss of power at all, and its only a 60 gallon tank. Most of your tools will be under 20 cfm... ratchets are liek 13 at full load, impacts are around 20... grinders are under 20, so its only a sander and blast cabinet that may tax the compressor, but the tank size wont really help you all that much. Honestly, I have no complaints about the 60 gallon tank... Ive never had a time where it was trying to keep up.

One disadvantage to the larger tanks is that they take longer to fill up... and therefor longer to catch up.

AS for the times, I dont have enough info to comment, but If you email eaton with your concerns they should be able to help you out. And they actually convinced me to go with a SMALLER tanks (less money so its not like they are out to just sell you something).

W-Cummins
01-24-2006, 12:54 AM
Just make sure you buy a unit that's 100% duty cycle (can run consistantly) and you'll have no issues keeping up with any tools / blasters / machinery.

my 2.5c

Finding a compressor that is really rated to run @100% and that will run in a home shop is not an easy task. Your talking rotary screw or a constant running piston machine with an unloader. The other machines you see are NOT rated to run 100% and you will burn them up if you do. They are made to cycle on and off. I looked into a rotary screw before I got the 20 hp quincy ( a really nice GD20hp) the problem with them is they are made to run 24X7X365 and the lowest run time on for that model was 15 min! So use up your one tank of say 120gal @120 psi and the unit turns on and runs for 15 min. Of course it unloads but you still have a 20 hp motor running. That is not a problem if your using a lot of air, but most home shops dont need a lot of air all the time.

W-Cummins
01-24-2006, 01:18 AM
I know. It will be mostly me, but my buddy might be using the air occassionally when I'm using the air as well. 80 gallon tanks are BIG and I'd like to stick with a 60 if at all possible.

All I can tell you is if you really want to run a beadblast cabnet or sandblast get the bigest compressor you can run. I would recomend a TRUE 7.5hp model as they are normally the largest single phase units you can get ( yes I know that there are some 10hp single phase motors but, they are not common and very $$. You could also run a tandem 5hp unit. Quincy makes some rather nice units like that. Just remember the cheep compressor manufactures LIE about their units HP ratings (some of them just settled a class action law suite about that) Also most air tool specs are for the MIN air requirements to just run them. To get peak output out of them they take MORE air. I have a little right angle CP sander 4" that I just LOVE, 23k rpm and super light weight. That dam thing gives my true 5hp 23cfm @ 90psi compressor FITS to run.. Cant have too much $$$ or too much air!!

kartracer55
01-24-2006, 08:41 PM
W-cummins...


20 HP?!?!?!?!?!?!?!?! :bowdown: What kind of air does that beast move??


A little known fact about those air specs is that they are based on 25% duty cycle... so your looking at roughly 4x that number to be able to run it continuously... I went into detail about this in another thread.

I wann know more about the 20hp compressor... thats FREAKIN INSANE!!!

Jim

drbill
01-25-2006, 08:40 PM
I just did a little checking on Snap-on air tools, most of the air tools I looked at used between 2 and 5 cfm to operate and a few of the smaller blast cabinets used in the upper teens.
I have a C-H single stage 3 cyl. 60 gal. compressor that I believe will do anything I need to do at home. I can give you a example of how much storage a 60 gal tank has. I needed to fill the tires up on my car so I could push it in the garage. The front tires are of normal size and both where almost flat, the rear tires are slicks that measure 28-11.5-15 and hold a large volume of air and they where down to 5 psi. I was able to fill both back tires, one front and the compressor didn't kick on until I was almost done with the second front tire. And I don't know if the tank was full.

kartracer55
01-25-2006, 08:54 PM
used between 2 and 5 cfm to operate


Average cfm... This was brought up in the thread titled "anybody have experience with this compressor?"

average cfm is cfm based off of a 25% duty cycle as I came across on a compressor reference site. You need to multiply these numbers by at least 2... 3-4 for continuous or near continuous running. My friend had a 5.7cfm compressor and a "4cfm" air ratchet... well, the compressor kicks on after the second bolt and by the end of the 3rd its faster to do it by hand.

I do use an air ratchet on my 60 gallon alot, and it kicks on for a little while then turns off like its nothing, so a bigger tank can help for low draw tools.

And I wanna find out more about whatevers runnin slicks on the back... :3gears:

Jim

W-Cummins
01-25-2006, 09:27 PM
W-cummins...

20 HP?!?!?!?!?!?!?!?! :bowdown: What kind of air does that beast move??

I wann know more about the 20hp compressor... thats FREAKIN INSANE!!!

Jim

It's a Quincy QR25 model 390. Quincy says that it puts out 69.21 ACFM @940rpm max continous 200psi. The pump is pressure lubed and weighs over 700lbs by its self. Mounted on the 120 gal tank and turning 877 rpm it makes just 64 ACFM and weighs about 1600lbs. When I start it, it pulls over 130 amps @ 480volts untill it comes up to speed ( that's about the same as 400 amps at 240 single phase). BTW it's the largest motor the power co will allow me to start w/o a softstart. I picked it up off flee-bay and I'm sure I was bidding with the "owner" in the auction but I really don't care as I still stole it at $500.00 the only thinkg wrong with it was the dumb asses tiped it over when they moved it to the guys house and bent up some of the stuff on it.

kartracer55
01-25-2006, 10:18 PM
Damn! I didnt realize it was THAT big when i say it in the picture.. haha I thought it was like a 60 gallon tank but now i see that the spray bottle is about the same size as the motor, which is HUGE... 64 cfm is just off the wall though. Seriously... How can you even come close to needing all that air?!?! The shop has a 7.5 80 gallon that provides air to 4 bays and there is never a fight for air even with the sand blaster going...

1600lbs haha!

thats just incredible, im blown away

Jim

Broncobilly
01-29-2006, 09:57 PM
Anyone here have a Husky or Cambell Hausfield 60 or 80 gal up right compressor (sold a Home Depot or Menards)? I believe most are 5 hp single stage? I would like a two stage Quincy or Champion 60 hp, but can't afford one. I was wondering, which of the big box stores 60 hp single stage compressor is best? They are probably mostly the same? Any input is appreciated!

mike goins
01-29-2006, 10:07 PM
Got a tractor supply in your area?
http://www.mytscstore.com/detail.asp?pcID=1&paID=1010&sonID=469&page=1&productID=9181

best deal ive found for single phase in the same price range as the other ones mentioned and IR is rated for continuous duty with the synth oil start up kit.

bmwpower
01-29-2006, 11:24 PM
Got a tractor supply in your area?
http://www.mytscstore.com/detail.asp?pcID=1&paID=1010&sonID=469&page=1&productID=9181

best deal ive found for single phase in the same price range as the other ones mentioned and IR is rated for continuous duty with the synth oil start up kit.

Damn! That IS a good price, however, I'm not sure of the IR model number to verify. Do you have any idea which model this is?

Remi
01-29-2006, 11:48 PM
Having just installed a 60 gallon with a friend. You will need some heavy duty lifting equipment to move around a 80 gallon.

evildky
01-29-2006, 11:51 PM
I got a 60 gallon purely based on size, it met my minimal cfm (19cfm@90psi) I'm sure the extra 20% reserve would equal less run time but not worth loosing the additional space in my case

mike goins
01-30-2006, 08:04 PM
It is the SS5L5 model that is a 60 gal .

http://www.northerntool.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=6970&productId=211720&R=211720



the TSC one is the same but has the 80 gal tank...

I have been looking for one myself. Seen alot of positive post for this model for cfm output and price range. The startup kit allows continuous Duty cycle which is a big factor to consider with compressors

john300k
01-30-2006, 09:02 PM
I got this Husky/Cambell Hausfeld for $425.00...killer price. At work we get 50% to 60% off all CP products...and free delivery to the shop.

john300k
01-30-2006, 09:03 PM
OPPs...this one

http://www.homedepot.com/prel80/HDUS/EN_US/diy_main/pg_diy.jsp?CNTTYPE=PROD_META&MID=9876&com.broadvision.session.new=Yes&CNTKEY=Products_2%2fPower+Tools%2fAir+Compressors+ %26+Accessories%2fAir+Compressors

john300k
01-30-2006, 09:06 PM
this one...

HUSKY
7 Peak HP 80 Gal 2 Stage Compressor

Model HS7810

Price: $869.00/ea