Jimmy_B

I will be purchasing an air compressor in the Spring. Might even get one for Christmas if I'm good.

I've never owned an air compressor, so please school me on what I should be looking for. I will be using it primarily for impact wrench, inflating stuff and general light duty use. Not for sanding or heavy use.

What CFM, PSI, Gallon Capacity, should I consider?
What brands should I consider?
What brands should I avoid?

Thanks in advance...

gearheads78

For your use about anything will work but run do not walk away from the pistonless type. You will be willing to commit suicide to not have to keep hearing them. They are not to bad at first and over a year or two they get so loud you can't think straight.

If you think you will ever do bodywork in the future get the biggest tank and CFM you can afford. I think mine is 11.5 CFM its OK but if I was doing it again I would go bigger.

11971four4two

I really like my portable electric rol-air compressor for the small jobs like you are describing.

http://www.rolair.net/

Jimmy_B

HAHAHA ! Thanks for the tip. So avoid anything that doesn't use oil...

Radarman68

CFM rating is what you look for to determine air volume. For the uses you are describing, a lower CFM rating will be fine. You would need higher CFM for sanding, sandblasting, etc and the lower CFM ratings are fine for nail guns, occasional use impact tools, etc. Look at the tank size as well, too small, it will come on all the time, too large, you wont have enough garage space. Higher pressure (175 PSI) compressors effectively raise your tank 'volume' size as well so higher PSI is better in my book.

Personally, I would suggest getting a vertical tank, 25 gallon, 175 PSI, oil free, two stage Craftsman air compressor. I know some of you may disagree, but I think the oil free ones are fine, just a bit loud. I never depressurize my tanks so the compressors always have air and only come on occasionally.

Get a name brand too, I would avoid the Harbor Freight specials.

dfire25

What CFM do you need then to run like a cutoff tool, or a sandblaster? Something that demands a constant air supply.

Radarman68

cuttoff tool like a nibbler takes next to nothing. a sandblaster or rotary wheel takes much more. but, if you have a 25 gallon tank with 175 psi, and run the tools at 100 PSI, you can run things for some time before running the tank below 100 PSI. I have a 175 PSI 80 gallon compressor that I can run my sand blaster about 60/40. in other words, run it for 3 minutes, rest 2 minutes, run it 3 minutes, rest for 2, etc and never drop below 120 PSI. I have a full size sand blaster and run it at about 75 PSI. I dont recall the CFM ratings off the top of my head, but IIRC mine is rated at 9.5 CFM or so (?).. this a little on the low side, but I make up for it with the 80 gallon tank and 175 PSI. lots of reserve surge capacity.

check out this page for some good info:

http://www.cpocampbellhausfeld.com/c...efault,pg.html

joe_padavano

CFM requirements are a function of tool quality. I have a Chinesium air cutoff tool. My 110V compressor can't keep up with it (I have a 15HP three phase compressor also).

The biggest thing to look out for is misleading horsepower claims. I have an alleged "5 HP", 110V compressor. If you do the math, it isn't physically possible to get a continuous 5 HP out of the energy in a 110V, 15A circuit. Look carefully at the fine print. Most of these compressors say something like "5 HP peak", which is simply the instantaneous startup HP that only lasts for a fraction of a second. The steady state HP is what matters.

Also, do you have the wiring to accommodate the compressor? A good 5 HP compressor will need a 220V, 20A circuit at a minimum. Get the highest HP and largest tank you can afford. Consider a quality US-made used compressor over a new Chinesium compressor.

garys 68

I've had a 110V, 33 gal, 150psi Sears compressor for 10 years. It may be a little larger than I need for garage use, but I've discovered things like cutoff wheels use a lot more air than I expected. And you'll never get frustrated by having too much compressor.
Sears has them on sale about every other week and usually has a deal on air tools with them.

Radarman68

I agree. if you can, use a 220v power source. Many compressors can be wired for either 110 or 220. when I ran my 110 compressor I had before, I commonly would trip the 15A breaker if I had ANYTHING else running on that circuit since the compressor pulled a full 15A at start up. I ended up pulling the 15A breaker and put in a 20A as a short term fix. I then had 220 wired in and upgraded my compressor.

again, buy as high a PSI and largest tank you can afford. and go with vertical tanks, as they take up less room.

droldsmorland

IMO if you can afford it and want to “step up” once, get a belt driven piston unit with a cast iron 2 stage compressor that spins at `1700 rpms. These will require a 220 outlet. This is the best. It will be quiet, last longer at the lower rpm and is easily rebuilt. You can change the oil too. Expensive though.
Your next choice IMO would be the Craftsman Professional Series 2 stage (or similar) vertical direct drive. I have one of these too. It’s not as loud as some of the DD units my friends have and I keep mine pumped up too like Radarman. The craftsman vertical serves most all my needs with general air tools. It was priced right too. I turn on the belt drive when I’m sand blasting, DA-ing, painting, 3/4" impact hammer or inflating the kid’s pool toys etc....

Ozzie

You have much good advice.
Try to accurately evaluate not only your current needs, but your future needs as well. If you continue with your interests, you will likely acquire more air powered tools. If you anticipate correctly you will reduce the chances of having to buy another compressor later. Most tools will provide air pressure and volume requirements. Consider which tools you might use and size your compressor based on the tools' requirements. When in doubt, it's better to go on the higher side if your budget and room allows. In the end, too big will have fewer problems than too small. I prefer the old fashioned oiled type compressors. Choose your accessories (separators, motor starters, etc.) carefully, and don't skimp on the power supply circuit. Starving a motor on voltage will not serve you well. Utilizing three phase power on larger compressors will be an economic advantage if you have it available. I have a reciprocating Ingersoll-Rand two cylinder (V type) two stage compressor. The compressor has served me well for about 30 years after buying it used. Be sure to do maintenance when needed; (change compressor oil, drain tank condensate, etc.)

jerseyjoe

I have been using the craftsman one below. It has worked for all my needs. I don;t use a sand blaster and rarely use cutoff wheel. Also, is very quiet, especially compared to ones without oil. Price has went up some from when I purchased but still appears to be a good deal when you catch it on sale. There is also an upright version. Keep in mind 1.9hp is running hp. Normal HP ratings are higher. CFM's over 5 at 90 PSI should run most tools....

http://www.sears.com/craftsman-profe...&blockType=G17

DeltaPace77

Lot's of good points brought up here, but I'd really get a good electrical feed out to my garage first. As mentioned, about 1.5 real hp is all a solid 20A 115v dedicated #12 wire power source will support. Get at least a dedicated 230v 30A service out there, if you're serious for up to 5 hp. Depends on where you're getting power from, as not not a big deal for me, with an attached garage. Just a matter of a #10 Romex cable run, you can get at Home Depot. As mentioned, a lot of cheaper compressors sometimes use bogus peak hp ratings, so check the unit plate amp rating against the two mentioned wire feed ratings. In reality, a good 1 hp motor, pushes 15A at 115v. Little electrical hand books are cheap. Don't forget the used market, as know guys that got good deals this way.

MDchanic

I think this thread has run off the rails.

Yes, sure, I would agree that a 220V, 2-stage, 200gal vertical tank compressor would be great, but look at the question that Jimmy asked.

He wants to run an impact wrench and inflate tires.

He specifically says he won't be using it for sanding or anything heavy.

A few years ago I picked up a used Porter-Cable pancake compressor, the type you use on construction sites and can can carry around with one hand, for $20, with a hose. Its on-off switch was stuck in the On position and its blow-off valve was weak. I spent $10 on a blow-off valve and have used the darn thing all the time for the past five years or so - it's easier to carry it out to where I'm working than to uncoil and drag the long hose from the big compressor.

For what you're doing now, that's all you need, and you can throw it in your truck (or car trunk) to bring with you if you need to.
If you can find one used, then you're really ahead of the game.



- Eric

hookem horns

Agree with Eric for what the orignal poster asked. I got a POS Harbor Freight special years ago that refuses to die. Have aspirations for something bigger & better, but it is fine for my light duty hobby usage.

Jimmy_B

Thanks Eric ! I was beginning to wonder how my wife would react when I told her we need to re-wire the garage so I can inflate the bike tires...

Seriously though, I do appreciate all the good information in this thread. This forum is an invaluable tool for learning. Opinions from those who have "been there - done that" are priceless in my mind. Thanks Everyone !!

DeltaPace77

Hard to say what Jimmy's really after from the original question, but was clear he wasn't after a 25 hp job. Gotta quote the importance of electrical service again. I have a nice Sears 1/2 hp compressor for filling up tires, and even that draws 9.5A. Painted a car car years ago with a 1 hp compressor, and kept running in the house, resetting the 20A circuit breaker. Keep in mind, motors draw several times their nameplate amp ratings upon start up. Thats why the house lights dim, every time they come on. If getting something to plug into a handy garage outlet, wouldn't recommend anything over a real 1 hp, 15A with maybe a 10 gallon tank.

charlierogers

ughhh, i remember a long time ago when all i had was something like this and was happy to have it. like eric said they are cheap and do the job on very small things. but i think you might be better off with something a little bigger if you can afford it. my second compressor i got for my house was/is a craftsman 6 hp {2hp running} 30 gallon upright 150 psi unit. it is about 10 years old and still works good. it is loud even compared to my bigger shop compressors 100 gallon 175 psi 220 volt units. but the price is pretty good on them. i think you can find them on sale in the 250$ range and they are great starter compressors for the price!