Guide to electric air compressors for home shops

[salty]

There might be a bit of a noise issue, too.

[Lew Hodgett]

Any decent spray gun will require around 15 SCFM.

Almost any air tool used for sanding, etc will need a lot of air.

Lew

[Chris Friesen]

Currently I only have a little twin-tank one-lung luggable compressor. A bigger one would be useful primarily for spray guns and air tools (drills, sanders, etc.). The bigger ones are also generally quieter than the little ones.

Also, most compressors aren't designed to run for more than 50% of the time. I was stapling down some sheathing with my little one and it was getting mighty warm.

Chris

[Ed Edelenbos]

Chris (and Lew and Salty), thanks. I'm knee deep in trying to sort all of this compressor stuff out. I'm at the point where I can't see much of a use other than a brad/pin nailer and maybe an airbrush now and then. Especially since I already have electric sanders and drills and dremels and such out the wazoo. There are isolated instances where an impact wrench would be a nice tool to have but not enough to justify the compressor it would require. I have come to the conclusion that a cheap little compressor isn't the most economical solution, though. The noise issue is one I've been sort of pushing to the background. Hmmm.... more data.

Ed

[Lew Hodgett]

Compressed air is like sex and money.

You never seem to have enough.

Lew

[salty]

You can buy a cheap little oiled air compressor with a 10 gallon tank for about $99-$200 that will be adequate for pretty much anything you will be doing around the house, including running framing and roofing nailers, paint sprayers, and other "normal" stuff. You may have to pause occasionally while nailing to let the compressor catch up with you, but it's not really an issue.

Here's a typical example:

've seen this compressor on sale for $100 with a rebate.

Lots of places carry something comparable.

[David Lesher]

And noise. Put it somewhere NOT where the people are. Use big shock mounts and flexible lines to avoid coupling.

[BobR]

And that advice would apply rather you are buying an oilless or not. While a slight amount of oil had very little effect on solvent based paints, that is not the case with today's water based epoxy and latex paints.

[B A R R Y]

Some of the auto paint shops in my area have switched to turbines and HVLP guns for use with water based finishes that get destroyed by the smallest amount of oil.

[Proctologically Violated©®]

What brand/model compressor is this? Price?

[Mike Marlow]

On Fri, 12 Dec 2008 06:39:36 -0800, Smitty Two cast forth these pearls of wisdom...:

As is true of most everything. We do however tend to fall back to the rule, rather than the exception, since for 99% of the folks, the exception is either out of their reach, or in some other way, not really applicable. That makes the rule (for all intents and purposes) seem more absolute.

I do agree that in the greater sense of understanding something, the exception should be noted.

[Mike Marlow]

On Fri, 12 Dec 2008 13:12:24 -0500, Ed Edelenbos cast forth these pearls of wisdom...:

Painting, especially if you are using HVLP equipment, air sanders (DA's), and some other air tools that are always on - as contrasted to the infrequent on state of say, an impact gun, or a nailer. For most home workshops, a little 30 gallon compressor with a couple horse motor is usually fine.

Whatever you do - think about how you will use a compressor. Look at the tools that you'll be using and find out the SCFM requirement of those tools. Add 50% - because the guy in you will most certainly buy more stuff down the road that requires more capacity from your compressor. Buy enough compressor to supply the most demanding tools, plus some.

Don't let anyone fool you - it's not about horsepower and all that other stuff people like to talk about. It's about SCFM - the ability of the compressor to deliver air. That is hands-down your primary consideration when looking at compressors.

Your secondary considerations are capacity (tank size) and duty cycle. You are not likely to use your tools in a home shop enough to really worry about duty cycle, but a good compressor will be rated for continuous duty. In tanks sizes - it's kind of like some other things - bigger is better. Smaller can get by, but bigger is better.

[Bob Haar]

You need to look at the SCFM rating at the pressure that your tools require.

[Proctologically Violated©®]

Home-moaner.

But as far as size goes, buying small-ish isn't necessarily a bad thing, as compressors are simply additive. Three small compressors should be exactly equivalent to one big one, with a few advantages:

1. You now have inherent staging, with all of its advantages: reduced electrical surge/"demand"; greater economy at low demand. Would proly need better pressure regulators in each unit, tho, as those in small units are usually not the best.
2. Likely quieter. Doubling the number of sources of the same noise only adds 3 db, vs. perhaps a much greater decibel increase of a larger unit. ie, two trumpets each at the same db is not as loud as one trumpet played more forcefully.
3. Smaller = portable, if nec.
4. May be easier to fit numerous smaller compressors in nooks and crannies.
5. Repair is easier, due to redundancy -- you won't be totally out of air. And Quincy's are nice, but I could proly buy a whole new small HD/c.h. for the price of one Q repair.
6. One can be set up for special apps, like painting, etc.

Proly some other advantages, as well.

HD/campbell hausefeld has a very nice upright 30 gal compressor, dual voltage motor, belt driven cast iron compressor w/oil, sight glass, wheels, VERY quiet. I would buy multiples of these in a minute.

Also, in many cases, larger resevoir volume is all that is needed, not a bigger compressor. I have numerous small makeup tanks for about 70 gals, works great with one small compressor. Would work even for air tools, depending on how much you use them vs. your total gallons.

[MikeWhy]

SCFM = "Standard CFM". Standard pressure = 1 atmosphere, or free air.

[J. Clarke]

Pedantry is not pretty.

[Greg O]

5HP on a 120 volt circuit? Somebody is pulling your leg, but looks like you realize it! I bought a Porter Cable 7HP, (sure you betcha), 60 gallon tank compressor a few years ago. Motor amps tell me that it is closer to 3 HP. It does all I want it to do. I can run any air drill, DA sander I have, and it just about keeps up. And what I mean by that is for a home, weekend warrior shop it is just fine. I don't drill or sand continuously for hours on end. By the time the tank starts to run a bit low I am ready for a 30 second break, and the the compressor catches up again. Really I don't even notice any short comings. If you planed on running a sander continuously with no break at all it will not keep up. In my opinion, most any one man home shop can get along nicely with 10 CFM at 90 PSI. Greg

[Greg O]

I will argue that point! Seems to me that the larger HP cast iron pump compressors are very quiet, certainly when compared to a 1HP oil less unit. My cheapy 7HP, (really about

3HP) Porter Cable is quieter than the 1-1/2 Craftsman it replaced. Much quieter than the oil less models we have at my job. Some of the 5HP cast iron compressors are strangely quiet. Low RPM pump and motor reduce noise a bunch, but at a premium price. Greg

[Tony Hwang]

Hi, My main goal was to use it to blow sprinkler system in the fall. What I got does it OK but very slowly. Wish I had a bigger one. Then I hve to run 208 circuit for it. As a compromise I am happy ith what I have. That Hp rating is bogus. They don't tell trun Hp, they invented a term peak Hp to fool general consumers. They do the same with stereo system. When they brag about 200W output power it is barely 50W rms.

[john]

If you paint and don't want to have any problems, get a bottle of dry Nitrogen and a good two stage regulator. NO oil No water that you can blame as to your quality of the paint job. :)

John