How to pick an Air Compressor?

[computerworks]

For those that have an air compressor in their shop or garage:
What are the specs to look for?
What's the difference ( or significance) between oil-lubed and non-oil?
I have looked at small portables (25-gal) and larger-tanked fixed units (60-80-gal)... what are the pro's and con's
Anyone pleased with a certain make and model?

I will be using it for shop tools - no painting.

All input is appreciated.

[62406]

Ron,
I have the sears 5hp 30 gal craftsman horizontal in my garage. I used it for building my garage 5 years ago with about 100 ft of hose and a nail gun. The only time it ever should "taxing was with a small sand blaster I used to clean rusty boat parts. The blaster was small, about the size of one of those fertlizer sprayers you hook on your garden hose. But it worked fine for the amount of time the sand held out. The things I looked for when buying were cfm and psi. Air boards are the worst! Air chisels next then air drills. My 1/2 in impact never kills my compressor. Look at tools you might think you will use "play a Tool time video" and then decide I think I got mine for 399.00 about 10 years ago and its still kickin. never broke down. Hope this helps. BTW mine is 220v Alex

[SSSnake]

We somehow got a hold of a 1957 Kellogg American, 5hp, 2 stage, 80 gallon compressor. It's out of a Gulf Gas station. It was burned out, so my grandfather bought it for something like 15 bucks. He rebuilt it and its still running strong. It is painted the same color orange as the Gulf GT-40's. It still has the original paint.

Glenn

[JoeLafives]

I had a 1/4 hp Monkey Wards compressor for over twenty years. Worked for most stuff. I recently upgraded to a 6 HP Craftsman to do some painting. If you're not gonna paint, something in the 3-5 HP range should be fine. Wait for a sale. I'd stick with Campbell Hausefield or Craftsman.

[kountzecobra]

Ron, buy as big of an air compressor as you can stand. I have a 7.5 hp Ingersoll-Rand with an 80 gallon vertical tank. It was about $1700 but after using up a couple $400 air compressors running DA sanders, air buffer/polishers, etc. the new one doesn't work hard at all. It mostly depends on your use.

[xlr8or]

I also have the Ingersol vertical unit. Can run any airtools from it and it never drops below 80 psi.
Used to have the horizontal 30 gallon but got sick of hearing it come after 15 seconds of tool use.
The bigger tanks are nice to have so you have the volume to maintain peak pressure throughout the job.


Scott

[sfry]

Ron,
Stay with the 220v single phase compressors. 6 to 7 horse and 60 to 80 gal tank will be great for all of your needs and future growth, piping ect.Smaller compressors seem to run more.(The more it runs the more it costs in electric and parts!) You dont want a compressor to run all the time unless it is a screw type. Typically screw type compressors are a industrial grade. Most sold to the average Joe is a piston type. More pistons the better and it will run more efficient. (my spelling sucks) Look at the CFM@90 psi. Try to get something in the 12.0+ range. The others seem to die off. As for brands- Speedaire,Ingersol-Rand and great. Campbell Hausfield is not as good but not a bad compressor. If you need charts on layout calculating size ect. let me know. I have helped many new shops in their purchases. I have the Campbell Hausfield 7.5hp and 80 gal tank for my home shop. I can paint cars no problems without any starvation. It wooks for me! You can also talk to Jerry at Hi-Line on your Island. Good Luck.

Shannon

[Excaliber]

I'm with 62406,,,,,5 horse, 30 gallon upright. 3/8th and 1/2 drive air ratchets work fine for even big auto jobs. Plenty volume\cfm. And the price, about 400 to 500 is good. Sanders and other "high volume" tools won't cut it with this size how ever. You will run out of air and have to "wait" for the compressor to catch up. Check out the cfm for your biggest air tool, decide how much "time" you will be running it and match the compressor\tank size to that tool.

I do very little sanding! I like my 3/4 horse carry around (oiless) for track use, I even change tires with it (1/2 impact gun). But I do have to "wait" if I use it to much. Oiless is NOT for extended use!

220 volt is THE way to go! Much more energy efficient and put you in a decent cfm size. Beside the 110 volt models are around 3 horse or smaller.

Ernie

[Double Venom]

I'm surprised that none of you guys have mentioned the difference between "Single stage and Dual stage" compressors.

Also Aluminum heads vs cast heads. Aluminum is light and the only plus as far as I'm concerned. They heat up to fast, (causing condensation in the tank AND your airlines much faster than a cast pump) and wear at a much faster rate.

A single stage is almost half as efficient as a dual stage- only compresses once during a piston cycle causing the compressor to run as twice as much or longer than a dual stage.

CFM is everything you need to know! A larger storage tank will obviously hold more air and require less running of the compressor.

If you really want to set it up right, run at least 20' of 3/4" "black" pipe, in any configuration if you don't have room for a straight run, keep it angeled downward-toward the compressor. (When condensation does build up in the lines it will run back to the tank vs. coming out your tools!)

5 HP - 220v, dual stage of any brand name will handle anything in a normal shop. (Paint guns actually use very little air, especially compared to every other shop tool!)

Buy a good quality "Dryer", Devilbis, Binks, Sharp, etc. to terminate your air line. Will add years to the life of your tools and are usually around $100.00.

DV---It's going to be a long winter.....

[62406]

DV, Good point on air lines. When I built my garage( of which I am slowly losing ground with. to tagsale items and lawn furniture, UGH!) Ithought I had everthing covered. The fixed air line would have been nice. The bigger tank also but my thoughts were under the work bench was the spot for it. After many years and oil dripping on the compressor I think I should have went for the verticle. I also looked at useable floor space and never figured on taxing a 5 hp. No one in my family ever even bought a 5hp for the house. But then again air tools was something I grew up only hearing in the garage my father worked at. 2 stage would handle anything and dragging an airhose around on a floor is a good way to get moisture in a paint job I'm told. I see a small amount in the air when Iblow off the line sometimes after draining my tank. Even with the dryer. Heated garage not heated floor. You can never figure everthing and NO GARAGE IS BIG ENOUGH! especially if your married. Heat, cable, phone, refrig, I was ready! Or I thought so! My sister-in -law promises to have her tagsale stuff out by thanksgiving. Yeah right! Alex

[J. T. Toad]

http://www.san-blast.com/technical/piping_dia.pdf

for a great set-up

[Junket]

D V is correct just like Big Block Small Block small ones 110v- 30 gal tanks single stage have to run hard try to keep up some time and still don't big ones 80 Gal 220v 5 Hp+ duel stage don't work so hard to keep up. I feel most any brand will work well for home shop use as long its of the large type.I would watch the paper and do that .One thing change oil once in a while on the poor thing the air it pumps has a lot of water
Ken

[Jack21]

Best place to buy a compressor, or for that matter, a myriad of other items is www.harborfreight.com.

You want an oil lubricated compressor, period. Imagine, your Cobra engine, or any engine running on polymer coated parts ONLY; no oil!? So why would you buy a compressor like that?

Agree with the dual stage vs single stage setup. More efficient.

You need to look at the air pressure (PSI), and air consumption (CFM - cubic feet per minute) requirements of the tools you own, or plan on using. Then size your compressor to meet the demand of the tool with the highest air consumption.

Next, you have to assess the electrical demands of the compressor. Up to about 2HP, normal 110VAC will do. Since the garage is usually where your electrical distribution panel is anyway, wire a separate 30 amp breaker to outlets just for the compressor and electric tools in the garage. This way, the (normally 15 amp) breaker doesn't pop when the compressor is running, and your spouse turns on the microwave or toaster. Over about 2HP, you'll need to install a 220 volt outlet to run the compressor. Make sure your home has 220 volt service before you buy the compressor. If you have an electric stove, an electric drier, or central air conditioning, you have 220 volt service running these appliances. You can tap your compressor outlet off the 220 volt distribution for these appliances.

My needs were quite minimal, a 1/2" air impact, and 1//4" air ratchet, pumping up tires, and cleaning parts. The $199.95 contractors pancake style 110v from Harbor Freight worked just fine.

[Ibr8k4vetts]

all I can says is stay away from the sears 5.5hp 60 gal craftsman horizontal oilfree model, what a hunk of c*#%. The rod flew out of mine one month after the warranty ran out Mike

[JAM1775]

Sears is running a sale this week in our NY area.
By coincidence I have been looking at compressors and just stumbled on to this thread. Guys..thanks for the education !
you guys totally talked me out of the $120 1.5 HP compressor even with the free accessory kit.
The 30Gal 6hp, 150psi unit is selling for $299.99 including
$140 in free air tools ! This includes 3/8" ratchet,impact wrench
fitings and 25' of hose. Wouldn't this be sufficient for the average wheel pull, tire inflator and outdoor sprinkler system
blow out usage ? Then again...a hydrualic car jack would be real nice !!

[Excaliber]

Jam1775,
30 gal 6hp for that price AND with the additional items included? Man, that rocks! Hydraulic jacks are fairly reasonable these days, throw one of those in to!

Ibr8k4vetts, Good point about oil less. I wouldn't go oiless on a larger than 110 volt size!

150 psi is a little mis-leading though. Thats a MAX rating, seldom if ever used. I'd set the regulator at about 100-110 psi. Higher is just not needed with a good size tank and the extra psi is really HARD on the compressor.

CFM calculation:
Look at the CFM rating at say 90 psi, a kind of standard. Some "cheap outifts" rate cfm at 40 psi, which is a total joke. 40 psi won't do squat! 7 cfm (for instance) at 40 psi might be 2 or 3 cfm at the REAL WORLD psi of 90 or 100.

Double stage compressor "way" better than a single Stage? Hmmmm,,,,,maybe not. Double stage will cost a LOT more. You need to do a cost benefit analysis. Single stage at the right price will work for me, (limited use).

Ernie

[Excaliber]

This is a GOOD thread. Gets right to the basics of a home shop and answers some fundamental questions. I think to often we overlook the "fundamentals". Well done guys and back to basics!

Ernie

[Ibr8k4vetts]

Also if you can try to hear the compressor before you buy. The crapsman compressor I had was VERY LOUD. Mike

[Double Venom]

JAM,

That IS a single stage compressor, with aluminum head. You have been warned, err...advised.

It's ok for limited use, bycycle tires, blowing out plumbing lines, etc. 6 HP may seem lilke a lot of horses for a compressor, but it will run non stop. Admittedly, most of us are thinking DA's, airboards, grinders, and impact guns, but you will have to trust me on this one, when you buy the compressor all these new toys will follow--and you will use them!

DV

[shnookie]

Good advice, DV. Whatever you do buy a CAST IRON compressor. The aluminum ones just do not last. I have a 6HP, 60 gallon upright and it has been with me for over 10 years. Made by PUMA. Cast iron twin cylinder. Get at least 11 CFM (I think the PUMA is 14) for running air sanders,etc. They can be bought for around 5-600 bucks. http://www.cumminstools.com/browse.cfm/4,65.html
Run 3/4 pipe, plumbing the garage with at least 4 outlets, with a quick disconnect at each outlet. Cheap insurance when two of you are working. Put a good air dryer at a low point in the line. If you really want to get fancy, put a small refrigerated air dryer, like a Hankinson, about 10-20 feet from the compressor. I bought mine used for 100 bucks. Then, put small dryers on the end of each line just before the disconnects.
Keep at least 10 feet between the compressor and the dryer. If you don't, the air will be warm coming out of the dryer and can still form a small amount of condensation. Air cannot be too dry for painting. Any amount of moisture will show up.
If you want to REALLY get fancy, bump out the garage and enclose it from the garage with an automatic drain valve. You cna't even hear it running.