Guide to electric air compressors for home shops

..There are six things you need to know about compressors: The maximum PRESSURE that it develops, the rated VOLUME it can deliver, the amount of compressed air it can STORE, how LONG the motor can run (which is also known as "duty cycle"), how much electrical POWER it's going to take to run, and how much NOISE it's going to make....

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Reply to
DC
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Hi, Also whether compressor is lubricated or not. Never get non-lubricated one. I have a Campbell Hauser Extreme duty belt driven compressor which can be powered by either

120V or 208V. I am running it on 120V plugged into regular wall outlet in the garage. For what I do it is adequate. It can even blow sprinklers in the fall.
Reply to
Tony Hwang

All the advice in the article is good stuff. One critical point is missing, however, The author should have added a section named "Delivery". More power is wasted by undersized or over long hoses and restrictive couplings than any other feature. The ubiquitous 1/4" Milton M fittings almost everyone buys are serious offenders in that respect. That is why so many shops for years kept buying air compressors with higher and higher tank pressure ratings. The currently popular 175 PSI rating is absurdly dangerous because design parameters of most air tools are by regulation pegged at 90 PSI. Milton some years ago introduced the "V" series plugs and couplers. These have substantially higher flow rates than the "M" series which

98% of the lads reading this now have in their shop. The specs are listed in the Milton catalog available (PDF) online. I converted my shop some time ago when they were first introduced to improve my HVLP paint systems. Couple this with a good quality 3/8" air hose (throw out those wretched 1/4" hoses) and a modest 125 PSI compressor will serve you very well for everything but removing earth mover wheels. The laws of physics will work for you if you let them.

Joe

Reply to
Joe

General rule for air compressors is buy the biggest one you can afford, because you always seem to need more air later than you thought. Mine is a "5HP" (yeah right) oiled reciprocating compressor which is just

*barely* adequate to run my abrasive blasting cabinet. Had I know I'd get one of those, I'd have bought a larger compressor in the first place, though what I have is about as big as you can run from a 120V circuit.
Reply to
James Sweet

If you are talking about using the compressor only for power tools and general use, I agree with the lubricated vs non-lubricated. If you plan to use that compressor for painting, I would recommend the non- lubricated. You don't want oil in the lines when painting.

Reply to
BobR

On Thu, 11 Dec 2008 18:21:06 -0800 (PST), BobR cast forth these pearls of wisdom...:

Not true. A lubricated compressor is better for all wood shop uses than an oilless compressor. The oilless models are throw away, light duty, short lived compressors, and they make a ton of noise. Whether the compressor is lubricated with oil or not has no bearing on its use for painting. I think what you were thinking of was whether to use a line oiler. Certainly, if you're going to paint with that system, do not install a line oiler. Simply oil your tools through the chuck, as needed.

Reply to
Mike Marlow

Good luck finding a single automotive paint shop, or pro business in general that gets by with an oil-less compressor. They're noisy, hot running things that burn out if you run them too hard. A good oil lubricated compressor exhausts a negligible amount of oil, and you need a really good filter and moisture separater in the line for painting anyway.

Reply to
James Sweet

ay.- Hide quoted text -

Admittedly, my post does not dovetail with this thread since you're talking electric motor driven compressors. However, I simply must brag and chortle about my air cooled DIESEL milsurp air compressor. Apparently it was designed to air up tires on jets. It's similar to the "wheel barrow" compressors that carpenters use. It has a single tank and a two stage compressor (175 psi!) compressor, belt driven by a Yanmar 3 hp, fuel sipping, air cooled engine. It is well balanced and light weight. It CHURNS out air. It starts from a battery or with a rope. I swoon over its efficiency, reliability, and fuel economy. In fact, I think I'll go give it a hug right now. Vernon

Reply to
Vernon

Admittedly, my post does not dovetail with this thread since you're talking electric motor driven compressors. However, I simply must brag and chortle about my air cooled DIESEL milsurp air compressor. Apparently it was designed to air up tires on jets. It's similar to the "wheel barrow" compressors that carpenters use. It has a single tank and a two stage compressor (175 psi!) compressor, belt driven by a Yanmar 3 hp, fuel sipping, air cooled engine. It is well balanced and light weight. It CHURNS out air. It starts from a battery or with a rope. I swoon over its efficiency, reliability, and fuel economy. In fact, I think I'll go give it a hug right now. Vernon

Now Vernon, you weren't over there squeezing her jugs now were you?

Reply to
Up North

Up North. Noooo. But I was tweaking her nipples! V

Reply to
Vernon

Oh boy, here you go again, pushing my buttons. I've expounded at some length about this in the past, but I'll be brief tonight. Cheap, shitty compressors are oilless. However, that does not mean that all oilless compressors are cheap and shitty. Mine is very, very good, and I sure as hell don't want oil in my air most of the time. When I do, I can add it myself. There's plenty of oil in your average oil-lubricated compressor to destroy a paint job.

Reply to
Smitty Two

you can bet large (and small) body shops don't use oil-less compressors. The good old fashioned kind been working fine painting cars for a hundred years now.

s

Reply to
Steve Barker DLT

You can bet anything you want. I rarely see a paint job that isn't orange-peeled, so my guess is that painters as a lot are as incompetent at their so-called profession as any other group. But I imagine that any decent paint shop would have some pretty good filters on the air, no matter how they compress it.

Reply to
Smitty Two

Orange peel has absolutely nothing to do with oil, it has to do with viscosity and method of application. Oil in the paint will cause fish eyes.

With any decent compressor you don't need a filter to keep oil out of the air line, just a moisture trap. The only large capacity oil-less comperssors I am aware of are screw type. All of the industrial rated compressors that most of us can afford for a home shop use oil to lubricate the bearings, and they have a pressure system that has a small oil pump - good brands are ones like Quincy. Not good brands are the stuff sold at the big box stores.

so, imagine away, but your inferences are incorrect.

above statement is just plain not true.

Reply to
Bill Noble

On Thu, 11 Dec 2008 22:10:59 -0800, Smitty Two cast forth these pearls of wisdom...:

Do you paint? I do. Never had an oil infiltration problem that was caused by the lubricant from my compressor. If you're encountering that, you've got compressor problems. For most people participating in threads like this, oilless translates directly to the cheap shitty stuff.

Reply to
Mike Marlow

On Thu, 11 Dec 2008 22:31:16 -0800, Smitty Two cast forth these pearls of wisdom...:

Water traps mostly. The previous poster is correct though, with respect to the type of compressor you will find in body shops.

Reply to
Mike Marlow

I visited a large number of bankrupt industrial places. Not one had an oil-less compressor.

There are good oil-less compressors out there, they are marketed to dentists and are very expensive.

I sold one in 2004. It was 3 HP, dual headed.

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I bought it from the military, as "broken, uneconomical to repair, condition H1" for $400. Turns out that what was broken was a tiny air line going to pressure regulator. A minute with a knife fixed it. It sold for $1,200.

i
Reply to
Ignoramus22904

I believe that screw compressors use even more oil than reciprocating, and need a big filtering system. (usually. a good article about hem is here:

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Reply to
Ignoramus22904

Yep. That's why every time someoone brings it up, I respond. My compressor is oilless. It was not cheap, it is not shitty, and it is about as quiet as a compressor can be.

My argument isn't so much about compressors as with the correlation/causation confusion that most people are too stupid to understand even if you 'splain it to 'em with a sledge hammer.

So instead of saying, "whatever you do, don't buy an oilless," I'd be happier if people would say "whatever you do, don't buy a cheap, shitty compressor."

Reply to
Smitty Two

Step 1. Decide what you need.

Step 2. Multiply that by 1.5 - 2.0

Step 3. Shop for a high quality two stage, or a two piston oil crank compressor if you only need a small one.

Step 4. Consider used, as you can sometimes get a killer deal on a big one.

Step 5. Install it right, electrically, piping, and air dryer.

Step 6. Enjoy and use, knowing you won't fry it, overwork it, or have it fall short when you need it the most.

My observations from not following these steps.

Steve

Reply to
SteveB

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