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06-13-2005, 06:08 PM #1
I'm in the market for an air compressor for my shop.
I've completed a search on air compressors, but the one thing I did not find was a concise discussion of the various brands and styles of air compressors suitable for home shop use.
Here are my parameters:
1. Less than $1000
2. Vertical Tank
3. 240 VAC Single phase, on a dedicated 30 amp circuit.
4. Low noise.
5. 10+ cfm at 90 psi
I'd like to hear opinions about the various options available, from places like Home Depot/Lowes, to Northern, to Harbor Freight, and others?
06-13-2005, 06:47 PM #2
This is a tough call, like lots of things, it depends...
However, a couple pragmatic thoughts:
1. STAY AWAY from oil less compressors. VERY noisy and not very heavy duty.
2. For quiet, get one that turns slowly.
3. When comparing compressors, make sure you are comparing apples to apples. IE, CFM vs CFM, SCFM vs SCFM, whatever. It's easy to mix all the propietary stuff up and not really know what you're looking at. HP is NO exception, you're better to compare the FLA (full load amperage) of the motor to get a better measure of its HP.
Might want to mention what it's intended uses are for more detailed help.
06-13-2005, 06:54 PM #3
06-13-2005, 07:42 PM #4
For low noise look for a cast iron compressor driven by a 1725 rpm motor. Anything driven by a 3450 motor is going to be a couple orders of magnitude more noisy, and the higher frequency noise is more irritating as well. A low speed compressor driven by a real 3hp motor would take care of what you're asking for very well, and would last a long time with minimal maintenance. Make sure you know what you're buying in actual terms, as stated above, and not the spin-doctored ad crap that can somehow rate a 3 volt cordless drill at 10hp
06-13-2005, 08:01 PM #5
Check out Eaton Compressors. I just bought a bare pump from them to replace our current tired compressor.
My 2cents would be to spend all you can afford to get a good unit that will be quiet and last for a long time.
06-13-2005, 08:05 PM #6
I have an IR T-30 similar to the one Smitty posted, bought 10 years ago.
The best thing I did to mitigate noise was to buy some rubber-footed swiveling leveling feet off eBay.
It got rid of the tinny racket and reduced it to a more satisfying compression noise.
I also backed off on the pressure switch, I run max 120 psi for my small air needs instead of the 175 psi as-delivered.
06-13-2005, 09:19 PM #7
Thanks for all the replies so far. Here are a couple of refinements:
I'd like to have enough CFM capacity to run a small bead blast cabinet that I will use intemittantly. I will also be running a D/A sander and jitterbug for some auto body work. I think those are my heavy hitters (as well as the super-inefficient Harbor Freight cutoff grinder)
The compressor RPM is something I overlooked.
The original question stemmed from looking at those 60 and 80 gallon Home Depot and Lowes compressors (Campbell Hausfeld?) They all seem to feature cast iron cylinders, etc. What makes one any better than the other?
What say ye on these brands?
Husky (Home Depot)
It alsos looks as though a 2 stage unit is within my budget. That seems to be the way to go.
06-13-2005, 11:57 PM #8
I own two Home Depot (Campbell-Hausfeld) units and one Quincy. Comparing these is like comparing a Hugo to a Rolls-Royce. I'll explain.
The C-H units carry large decals stating "Made in the USA". So when one of the motors started making funny noises (dying bearings) I expected that the Marathon USA motor might have quality bearings. Any company with a name like Timken, SKF, Fafnir, etc. More than a little disappointed to see only CHINA stamped on both bearings.
More? The check valve (located at the top of the tank) stopped functioning, it would not stop back-flow after motor shutoff. Okay, just unscrew it and look for tiny debris. Except that the assembler had cross-threaded the check valve. Well, I'll call the 1-800 number & get a new one. Six phone calls and half an hour later, have yet to speak to a living person. I could go on.
Quincy? www.quincycompressor.com/ Made in the USA by a company that makes air compressors. Priced about 50% higher than the Big Box Stores. Why? Well, the machines are nearly bulletproof. Heavier construction, overengineered (which is why their 135PSI pump is also used on some 175PSI applications). Not only do they answer their phone, they know how to answer questions. And provide service, like free replacement parts for a unit that's many years out of warranty. And recording the name of the buyer, seller, date of sale, etc.
Will the Quincy last 50% longer than the semi-USA/semi-China units? No way. 100% longer, at least.
06-14-2005, 12:08 AM #9
There is some excellent compressor background info that Forrest had written some time ago and is stored in the archive. Should be required reading before going compressor shopping.
06-14-2005, 12:14 AM #10
Erik, the brands you mentioned are pretty much all 'Brand X'.....basically hobbyist grade equipment.....and would probably perish pretty rapidly under the continuous service needed when running a blast cabinet.
Your chance of getting an adequate compressor as a new unit for that $1000 budget are nil.
Your best choice is to find a good used 7-1/2hp 3ph unit in one of the good standard makes, and fit a 5hp single phase motor, preferably in the 'Baldor' make, with a motor pulley proportionally smaller to drive the pump a 1/3 more slowly.
The next best choice is a 5hp in any of the good makes, and replacing the three phase motor with a single phase unit.
What are the 'good makes'?
First, the Quincy make, with pressure oiling
(the industrial grade Quincy, that is....they put the Quincy name on a hobby grade compressor also, these days....the difference is obvious)
Next, the Curtis (Curtis-Toledo) which is 'ring oiling' and a high quality reliable unit.
Next, the Saylor-Beall....splash oiling, but a good unit....we have a couple of these, and they have been reliable in service....
Past that, the older DeVilbiss, Kellogg-American, and Worthington were good compressors.....I'd check on parts availability before buying one, tho.
Parts?....yes, parts.....the best deals on compressors....cheap, sometimes free for hauling it away....are on units needing overhaul.
Rebuilding a compressor is just like doing a small engine, but simpler and easier....the good makes use valve discs and springs, which are easily replaced, not terribly costly, and often the only thing wrong with an older compressor.
06-14-2005, 12:57 AM #11
Search the archive. This topic comes up repeatedly, including within the last couple months. The answer is always the same: get a used, quality (IR, Quincy, etc), two-stage industrial type. Don't even think of Home Depot, 3450 rpm, fake-rated motor, oil-less, etc. or you will be disappointed with the wimpy output, the ear-splitting noise, and the crappy reliability. When I wanted one a couple years ago, I called up the air power sales and service companies in my area and within a few hours landed a newly rebuilt IR with 80 gal tank for $300, then got a used 5HP 220v single phase motor from a motor shop for <$100.
06-14-2005, 01:06 AM #12
The pressure you desire determines a lot and seperates 2 main categories in your price range. Single stage (where all the pistons pump the air to the receiver) is good for generally 120psi. As they operate at lower pressures they can move a large volume on a small motor. 2 stage (where one large piston compresses and shoves down to a smaller piston which boosts the pressure) are generally rated at 175psi. This pressure generally takes more HP. The higher pressure allows longer cycling times, but makes the compressor work harder.
a note: Many compressor manufacturers have 3 models looking the same but have different cfm ratings..this is acheived by mounting different sheaves and running the compressor at a higher rpm this in turn takes a higher hp motor.
A single stage sounds as if it would do all you want but at your budget 2 stage would be better....get the biggest receiver possible and plumb with big lines, I mean big. These act as a receiver and cut down on cycling time.
Some real life experiences: We have in our shop a "cheap" Campbell Hausfeld castiron 2 stage splash lube pump. It has been on the duty for 23years now, never down. Next door in our casting plant we bought a brand new "made in USA" Curtis 30 hp job 2 months ago....blown up last week. They've been in here 3 times to fix that pile of junk, no joy. It vibrated so bad it broke the legs off the pulley gaurd, intercooler, split the hose, and cracked the receiver next to it all in 2 weeks. Now the bearings brinnelled and fell apart. Hope they're better at little ones than they are at big ones. China is gonna have our lunch.
06-14-2005, 01:13 AM #13
those lumber yard compressors are only good for one thing ..putting more dollars in a bank in bejing so they can use it to build nuclear subs and cruise missles using american designs ...I'd rather have one old cast iron pump made in USA than a whole ship load of that chi com crap ..
06-14-2005, 01:24 AM #14
Thanks to everyone who replied. Mark, I did search the archive before posting, and found a lot of good information (including Forrest's advice thread), but it was fragmented. I wanted this discussion to focus on the specific needs of a home shop, and identify the inadequacies of the "big box" store units...which are oh-so tempting by their low price and convenience (they are 10 minutes away).
Having said that, thanks for the excellent education of quality named brand compressor manufacturers, both past and present (Carla, et al). Howwever, it looks like a new Quincy industrial unit might be a little out of my price range.
However, I started doing some research on the Eaton brand of compressors, and they appear very impressive. The 5hp 2 stage unit is slightly out of my price range at $1100 but I suspect that it would be money well spent. Seems like a forthright company that stands behind their product, judging from their website.
Does anyone have any firsthand experience with their products? I'd love to hear a report about the performance and satisfaction.
I did some poking around on Grainger's site (thanks for the link Smtty58) and discovered this compressor from Ingersoll-Rand. It is a 85 gallon, 5 hp TWO STAGE for $696. Is this a last year model on closeout? With my company's employee discount of an additional 10% is this a no-brainer? Info can be found here.
Additionally, I can offer firsthand experience on those oiless 6.5 hp (with about 45 "peak" hp right? ) from Sears. My dad made the mistake of buying one several years ago. It is unbelievably noisy. We can't be in his 3 car garage with that thing running. He regrets buying it every time he turns it on. I think the only reason it hasn't blown up yet is because he hardly ever uses it.
Thanks for the tips and sage advice. I really enjoy this forum due to all the informed opinions.
I'll also start looking local for compressor service places to see what the used market looks like.
06-14-2005, 01:24 AM #15
They are not THAT bad, I've been using a Husky for over a year running a VMC, bead blaster and various air tools. It's loud as hell, but...it works, and it was under 1k delivered to my door. If it ever poops out I'll post it up here.
Some day a nice big Quincy screw compressor, for now it's Husky :rolleyes:
06-14-2005, 02:02 AM #16
Re: your question about the difference in IR's $696 model and the "standard" $1,299 model.
A five HP, 220 volt single-phase motor shoud draw about 28 amps. The less costly compressor draws 22.5 amps which makes it a four HP motor. So right off the bat you have twenty percent less power than the other unit. All else being equal, the lower cost unit will run 20% longer per cycle, and wear out 20% faster.
In addition to the higher HP motor, the $1,299 unit uses the Type 30 pump, so named because it was first built in 1930. Here's a quote from IR,"In the year 2000 we ran a competition to find the oldest operating Type 30 in the country and found one in a service station near Swan Hill that had run continuously since 1934! The cast iron construction, two stage intercooled design and computer-optimised cylinder head and valve layout gives theType 30 it’s unique ability to operate up to 175 psi on a continuous duty cycle, and still run cool. The Type 30 epitomises a design philosophy which allows all wearing components to be individually replaced (no "unit" replacements here). There is unquestionably no better, more reliable or longer-lived air compressor than an Ingersoll Rand Type 30."
The less costly unit uses the new Type TS pump. Couldn't find anything on the IR site (or any other site) about the TS.
It would appear that IR doesn't want to lose market share in the under $1,000 category, so they brought out the $696 model.
06-14-2005, 02:16 AM #17
I have an old IR 5 horse 60 gallon upright 230v compressor that I bought used, and have had for 6 years or better, and untill I moved that thing was used 4-5 hours a day every day (a working garage, auto body/paint and mechanical repairs) when I moved it sat at my mothers house for a year because my current house doesn't have 220, (not even run from the pole) needing a compressor, I loan swapped my IR for a friends 5hp airless type 110v,cambell hausfield, used it once and threw it in the shed, the thing is far too noisy, and any real use makes it run constantly, so I use my antique, pulled out of a dumpster 3/4 horse 1725rpm, it's slow, and I have to pause every now and then, but at least I don't want to put it in the neighbors garage! thinking of plumbing the old 3/4 horse to the CH tank for more volume.
stay away from the big box store stuff, they don't hold up as well.
Also,my other friend got a husky for Christmas last year, and it won't build enough pressure to do anything, home depot says basically it's his problem.
06-14-2005, 02:28 AM #18
I have a Porter Cable (Devibliss) 6HP (yeah, right) 220 motor and have been happy with it for home use. Has a domestic GE motor and does not make a lot of noise. Don't think that I would buy one for any real use, but for light use it ie great. The Ingersoll unit that you found sounds really good. Try to find out who made the pump (everyone seems to be using POS imports with more sand than iron in the castings) and motor if possible, but it looks like a good deal.
06-14-2005, 02:35 AM #19
A minor point, but your current draws seem a little high?
By my calculation, at 240VAC with an efficiency of .85 and a power factor of .8, I get a current draw of 22.85 amps at 5 hp.
Equation: I = (746 * hp) / (eff * pf * voltage)
This is assuming a resonable efficiency, and a power factor for full load running requirements.
Maybe I am not correctly considering starting vs. full load running requirements?
06-14-2005, 02:42 AM #20
This is a bit off topic but was mentioned...food for thought.... the man wants to use a jitterbug sander. I have a top notch Hutchins DA. When in use sanding away that 220v 5hp 25amp compressor motor rarely shuts off. I also have for wood working a Porter cable electric DA, it draws like 4.5 amp and runs all day. Air for air tools ain't free. I virtually have a 5 hp motor in my hands when using the Hutchins. Hmmm