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Does Size Realy matter...

hdossett

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Joined
Jun 22, 2009
Messages
384
Location
N. Central AZ
When buying a compressor?

Looking to buy a decent compressor for my garage. Will not get a lot of use.

Wood working nailers, air ratchet and impact, tire inflating, etc.

Which is more important, Tank Size, HP, SCFM @ 90/40 PSI, Max PSI, oil vs Oilless?

And how do all of these parameters relate. There seems to be no rime or reason in their relationship. Is there and advantage to a 230 Volt unit, wiring is not a problem? What about upright Vs. Horizontal?

I currently have a Porter Cable 6 gal pancake 150 max, 2.5 SCFM @90. It is greater for nailers and tire inflation. Not much more. I plan to leave it in my RV.

Looking @ Harbor Freight @ these units.

....................................................SCFM
.......HP......Gal......PSI......Volt.....@[email protected] Price...Sale../...Coupon price
1......3........10......115......120.......5.6.....7.2......179.99........139.29.......$111.43
2......3........21......115......120.......4.3.....4.9......199.99........N/A............$159.99
3......4........29......120......230.......7.7......8.7.....369.99.........N/A...........$295.20
4......3........21......115......230.......3.5......8.8......219.99.......169.99........$135.99
5......3.5.....25......125......120........4.2.....5.5......249.99........249.99........$199.99


SKU's 1 90234, 2 94667, 3 94667, 4 93271, 5 99925

#1 is currently front runner! (price/SCFM)

# 3 looks great but over budget for now. (But on a good sale w/coupon might be doable)

I am not in a hurry, getting ready to go on a 3-4 month road trip, so I can wait for sale prices.

Recommendations anyone?
 
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bitbycarbug

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Feb 21, 2010
Messages
364
Throw out SCFM, it's a marketing ploy as it stands for Standard CFM but whose standard they use is anyone's guess. It's usually in ideal conditions as temperature and other factors can impact CFM.

Tank size will determine how often the compressor will have to run to fill the air back up.

HP motor size will determine how much CFM it can produce working and how quick it can refill the tank.

Generally, most of your air tools will tell you not to exceed 90 psi and its a good pressure to set the regulator at to keep the tool going for a long time. All your tools should something that says how much CFM the tool consumes at 90 psi.

Max PSI: Don't really know the advantages/disadvantages

Get an oil compressor as they do last longer than oilless. Oilless also tend to be the smaller compressors.

230v will be more efficient, let you run a bigger motor, and keep a dedicated breaker for the compressor. It's probably going to require a 30 amp breaker at least.

Upright is recommended as they take up a smaller footprint in your garage.


For $250, search craigslist as you can find a decent 5-7 hp 60-80 gallon unit. I picked up a craftsmen professional 7 hp/60 gal for $300, hardly used. I can run impacts, grinders, and smaller air tools with absolutely no problems. Painting and running a DA I have not tried, but doing a fender or small area should be no problem. I could do a full car but would have to wait for it to recharge and I'm impatient :)

Remember to not shop for a compressor that will fit your needs now, but it will fit the bill for future tools. If you want to sandblast, paint, or run other heavy CFM tools, shop for a big one now, so you don't have to buy twice.
 

930dreamer

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Staff member
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Oct 7, 2009
Messages
23,048
Location
Amarillo,TX and Stinnett,TX
FYI, if you plan on being in the same building as the compressor, don't get an
oil less model. The HF items would be my last choice(thats just me). A 220v compressor would start you off with a better piece of equipment. I bought this industrial Champion for $99, but my needs are a little different.
 

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tcianci

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Feb 7, 2009
Messages
4,242
Location
Walpole, Ma
CFM at a specified delivery pressure is the most important parameter in selecting an air compressor with respect to whether or not it will meet the needs of your tools. A larger tank simply indicates that the machine can hold more air at the specified pressure and that changes the duty cycle of the machine. The less time the machine has to run to deliver a certian quantity of air, the better, there are lower operating temperatures that lead to less condensation and less noise more of the time.

You have selected well among the models that you have listed. In reality, it's hard to ever say that you bought a compressor that was too big.

Notice that once you get to the real lightweights, you can look all over the place for the CFM specs but they are either in the fine print of missing all together. When the first thing they plaster all over the ad is the HP or the pressure, that's a sure fire give away that you're looking at a machine that doesn't have enough poop to pull a fat girl off a tricycle.
 

moronmountain

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Joined
Apr 12, 2010
Messages
499
Location
Oregon
Sorry if I'm hijacking, but what is a good compressor for running air tools, and possibly painting with?
 

54FordPanel

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Aug 7, 2009
Messages
5,711
Location
Fort 54, Littleton, Co
My recommendation is to buy the biggest compressor you can afford, and don't get a oil-less style, no matter what. Unless it's just a little pancake compressor for your nail gun, and for hauling around to job sites. Then they're ok.

But don't get a oil-less for your garage. Eliminate them from consideration. Every time my big ole Champion fires up, after listening to my annoying Craftsman for years, I want to hug it.
 
OP
H

hdossett

Well-known member
Joined
Jun 22, 2009
Messages
384
Location
N. Central AZ
OK, looks like my dyslexia took charge when entering the data in the OP, some of is screwed up.

I think I have decided on ... ITEM 94667

3hp, 21 gal., 115 psi cast iron Vertical

Motor: 120 volt, 60 Hz
Air delivery: 7.0 SCFM @ 40 PSI, 4.9 SCFM @ 90 PSI, 4.3 SCFM @ 115 PSI

http://www.harborfreight.com/3-hp-21-gallon-115-psi-cast-iron-vertical-air-compressor-94667.html

I can't see ever wanting to work hard enough to ever need more air than this!


$129.99 with Coupon here

http://www.harborfreightusa.com/html/SingleMagLanders/truckinclassic/truckinclassic.html

Had to search all the coupon pages @ http://www.harborfreightusa.com/html/SingleMagLanders/ to find one not expired!

Called to check inventory before driving to Phoenix tomorrow, Amanda said they had 44 of them. Seems like a lot, just hope my dyslexia wasn't in charge when I gave her the item number!

Again, thanks for all the help.
Harold
 

BOONEY7750

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Joined
May 13, 2010
Messages
147
I just went through all of this; I wanted a compressor that could run small air tools so I wanted at least 5.5 SCFM at 90 psi. I am restricted since I have 15 amps for the “garage” which is really just a shed like structure that was an old kitchen in the 1800’s. Space is critical. I found the perfect compressor for me on Craig’s List. 2 H.P. 5.8 SCFM @ 90psi, but most importantly max load draw is 15 amps, 110v. Unfortunately it is a crapsman and oiless. However it is only twelve gallons so it takes up little to no room. I plumbed it in with an 8 gallon auxiliary tank both of which are in the pitches of the roof line above usable shelf space, so I basically solved my space issues, and power use issues, and still got the minimum SCFM I wanted. I know I can’t paint or even really use a big die grinder or drill but, until I can rewire I can use impacts, framing nailers, and blow up 35 inch tires.
An important note would be I would not buy this if I wanted it to be my end all be all final air compressor. I know down the road when I build THE SHOP I will be getting a multi phase cast iron 230v compressor, so I found a happy median.
 

BOONEY7750

Well-known member
Joined
May 13, 2010
Messages
147
P.S. If anyone on here did "over buy" on thier compressor and they are unhappy with how overpowerful it is let me know, I'll take it off your hands!
 
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