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Air Compressor recommendations?

Bill Wightman

Bill Wightman

Well Known Member
I'm setting up a new shop and am in the market for a nice air compressor. The last two I've had were REALLY loud, since they had single stage pumps.

My shop needs include all the usual air tools, and I want to be able to run a medium sized blast cabinet. The blast cabinet will most likely be the largest demand on the air system. I want a 2-stage pump for quiet operation.

So far, the Ingersoll Rand 2340L5 and the new Craftsman Professional 80 gal 5.4 horse model look good to me. One question: when looking at electric motor HP ratings, are those supposed to be the continuous rating, or some kind of peak or start up rating?

Any recommendations, good or otherwise would be appreciated!

Thx...
 
Actually, single stage and two stage compressors aren't significantly different in terms of noise levels. That has more to do with whether they're oilless or oil-free -- the oil-free ones are really loud.

Two stage compressors WILL outlast single stage ones because they run cooler, however.

As far as ratings go, I've found that it's very difficult to compare the manufacturers' numbers -- whether it's for HP or anything else. (The HP developed by the motor has very little to do with compressor performance, for instance.)

FWIW, I'm about to replace my compressor as well, and I'm going for a two stage one from Home Depot (believe it or not) -- their Husky Pro model #HS 781004 AJ is reportedly an excellent entry-level two stage compressor for the equally excellent price of $1076. And HD currently has an instant $300 rebate on it.

Have fun -- I've been researching compressors for six weeks now!

-- Chris
 
Thanks Chris

Come to think of it, both of my other compressors are "oil free". The one I'm temporarily using is so loud it sets off the glass break sensors in my shop when it starts up.

Thanks for the recommendation on the Husky. I'll take a look!
 
Yes but

Perfect for painting..:)

I couldn't live with it in the same space as me though!

Frank
 
CJK said:
Actually, single stage and two stage compressors aren't significantly different in terms of noise levels. That has more to do with whether they're oilless or oil-free -- the oil-free ones are really loud.

I have to disagree here. I will agree that the oil-less are MUCH louder, but 2-stage are generally significantly quieter than single stage. I can stand next to my 2-stage and carry on a normal conversation. I've never seen a single stage that quiet.

Two stage compressors WILL outlast single stage ones because they run cooler, however.

They also run at a lower rpm.

As far as ratings go, I've found that it's very difficult to compare the manufacturers' numbers -- whether it's for HP or anything else. (The HP developed by the motor has very little to do with compressor performance, for instance.)

I agree that hp has little to do with performance. HP ratings nowadays are a joke, at best.
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Added words to become postable.
 
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Mel, I'll defer to you on the two-stage versus one-stage noise -- I bet some of the ones I thought were two stage compressors were really one stage compressors with two cylinders.

-- Chris
 
Bill,
I've been running a 5 horse Campbell Hausfield 80 gallon cast iron 2-stage for about 10 years. Can't complain.

Best noise reduction move was to bolt some 6"x6" birch ply pads to the feet, then glue 1/4" thick silicone rubber sheets to the bottom of the pads. Amazing how much of the low frequency noise is transmitted via the concrete slab.

If you can, install a 1/4 turn ball valve in the bottom of the tank, hook it to a length of flex hose, and plumb that to a hard line that runs out through the wall. Makes tank draining easy and mess-free.

Run your blast cabinet dust collector outlet through the wall too.
 
CFM

Look at the CFM rating at 90 psi. You want something that can deliver over 10 cfm at 90 psi. HP ratings are a joke since some list the peak HP not the continuous HP. Keep in mind that two stage compressors usually have a much higher tank pressure like 150-175 so you will have to have a regulator to bring that down to 90 or output. I've heard horror stories of people running 150 psi+ and having tools blow up on them.
 
Dan, great ideas, thank you. I've taken a look at the Campbell Hausfeld models and they look very good. The new Craftsman Professional line looks good also. The vibration insulated base makes sense.

Wingtime - HA!! I can't imagine trying to drive those AN426-3's with 175 psi behind the rivet gun...


One other question: What do you use to plumb your air in the shop? Schedule 40 PVC? Will that work safely up to 175 psi? I'd like a safety factor above that too.
 
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Careful with PVC

I really wouldn't recommend it..PVC is notch sensitive..It has been outlawed as compressed air piping in the UK at least and (although I have never checked) i bet it doesn't meet code in the US.

CPVC I believe is a better material choice.

Frank
 
CJK said:
Mel, I'll defer to you on the two-stage versus one-stage noise -- I bet some of the ones I thought were two stage compressors were really one stage compressors with two cylinders.

-- Chris
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The easiest way to tell a 2-cylinder single-stage from a 2-stage compressor is that on the 2-stage compressors, one cylinder is smaller than the other, the smaller one being the higher pressure stage. Also, if you look close, you'll notice that the 2-stage cylinders are plumbed in series, whereas the 2-cylinder single-stage cylinders are plumbed in parallel to the tank.

I had never thought about the RPM being lower on a two-stage, but thinking back, my dad's 2-stage compressor with 90-gallon tank does run noticeably slower than my Craftsman single-stage roll-around. IIRC he bought that compressor when I was 16... that's 37 years of regular use without a problem.
 
<<What do you use to plumb your air in the shop?>>

Ordinary 3/4 steel pipe with 1/2 drops for the taps and water traps. If you want to run a bead blast cabinet, you need to get the air dry.
 
longranger said:
The easiest way to tell a 2-cylinder single-stage from a 2-stage compressor is that on the 2-stage compressors, one cylinder is smaller than the other, the smaller one being the higher pressure stage. Also, if you look close, you'll notice that the 2-stage cylinders are plumbed in series, whereas the 2-cylinder single-stage cylinders are plumbed in parallel to the tank.
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Thanks, Miles -- when I went and looked at the Husky Pro I'm planning to buy, it's exactly as you say: one cylinder is significantly larger than the other. The other multi-cylinder ones I've seen all had the same size cylinders and each directly connected to the tank.

Bill, FYI, Campbell Housfeld builds the Husky Pro model I mentioned above.

-- Chris

P.S. This is a great thread for those of us just setting up our workshops!
 
Anyone used plastic pex pipe?
Flexible and easy to install. Won't rust from moisture.
Will need to check on the pressure it can handle, Although I have heard of it being used.
 
Shop plumbing for air was just hashed out on another forum I visit. The distilled essence is roughly:

PVC: Never. It shatters like glass when it fails.

Copper: Assuming a temperature of 200F, 2" type K drawn (hard) is good for 747 PSI, type L drawn is good for 625 PSI, type M drawn is good for 514 PSI, and type DWV (the thinnest copper) drawn is good for 373 PSI. Note that the above is irrelevant if you use the wrong solder....if you use 50/50 tin/lead the safe working pressure at 200F is only 50-90 PSI, whereas using 95/5 tin antimoney it would be good for 180 PSI if he is using type DWV tubing, or 395 PSI of using type K, L, or M.

Black Iron pipe: Most economical choice, but you may have to deal with rust flakes. Advised to install a filter/seperator before any tools or regulators.

PEX: There is a version rated for compressed air, info at http://www.flexalpex.com/

Rubber air line: For a typical garage, a 50 foot hose, some barbed tees and assorted fittings and hose clamps can plumb up a small garage on the cheap. Just cut the hose where you need a hose drop and tee in a fitting. Zip tie it to your rafters. Its easy to modify or add fittings as you need.
 
Now that I have my airplane at the hangar, real cool. I needed a compressor there. I went to Best Buy and almost bought there Husky compressor. Than I had this feeling to go to Sears and check out their compressors. I settled on the Sears. A 25 gal professional compressor. I guess the kicker was, 40% quiter operation that did it. Sure nuf, I set it up in the hanger and turned it on, very quiet. It runs my air tools very nicely, even the cut off wheels and air drills. The part no. is 16778. I do like this compressor. It is a stand up model so it goes in the corner real nice. I use 3/8 double braided fuel hose for all my air lines, it's nice and flexible. I put ends on for the T style connections, 25ft. long. I have two of these hoses that I connect together if I need it.
 
Flexalpex tubing

Mike - this product looks really great for plumbing the shop. I assume plumbers would be able to make all the hookups.

PEX: There is a version rated for compressed air, info at http://www.flexalpex.com/
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I didn't see a pressure rating on this stuff on the website, but they do have an application list, including "compressed air". I'll look into it. Thx.
 
Oh, man. I'm in lala land with the airplane right now. That's Home Depot. I'm doing engine run after lunch.
 
I plumbed my house with Kitec, which is a variation of pex but it has an aluminum core, and its rated for air. If you bend it, it stays bent. A friend of mine plumbed the air lines in his shop with Kitec.
 
I wish I had at home what I have at work.

At work we have 2 packaging machines that rely heavily on pneumatics.

We have a Vertical Tank3 phase 2 cylinder 7hp SpeedAire model from Graingers.

It puts out a lot of fairly cool air relatively quietly, while running at about 50 % capacity. It automatically drains the condensation in the tank every time the motor shuts off.

At home I have a vertical single phase 5 hp hand me down, rebuilt compressor, low end Devilbiss. Its great for anything with an air motor because there is always enough petroleum mist to keep them lubed. On one outlet I have a pretty good separator with extra filter and a clean hose for paint.

I always use a new disposable filter at my paint gun for each painting session.

I wish I had at home what I have at work,:( but I can't justify $2700 bucks when I am almost done painting anyway.
 
If you live in a climate that freezes don't use PVC, The pipe will fail sending Plastic missiles throught your work shop believe me I know first hand....you don't want to be standing in front of the line when it fails... The best is Coper Lines. Steel Lines will rust inside so you will need some kind of in line filter and water seperator, before the regulator
 
If anyone gets an oiled compressor ... Do Not lay it on its side for transportation.

.....Don't ask me how I know :eek:
 
RapidAir

This system is what I'm planning to connect to my new compressor to provide a couple of wall mounted air outlets as well as a ceiling mounted outlet to connect to a hose reel. I'll provide a pirep as soon as the parts arrive.

-- Chris
 
Has anyone used an Eaton Compressor? www.eatoncompressor.com/?

They sure talk a good talk about quiet (although 73 DB is not quiet). My wife goes to bed early, and the garage is directly under the bedroom, so this is muy importante to me.

Also, thinking about purchasing just a bare compressor pump from these guys to convert an oil-less p.o.s. to something usable. My current compressor has a 27-gallon tank, so am interested in other's opinions on this point.
 
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