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Thread: Air compressor confusion

  1. #1
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    Default Air compressor confusion

    Okay, Iíve read a few, seems like millions, of posts on air compressor size. Do I need a dual stage compressor or a single stage compressor in my garage. My plans are for air tool use, not professionally, and occasionally some paint work. Can I get by with a 60 gallon single stage unit or do I need to fork out the money for a two stage unit.
    Thanks

  2. #2
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    Nov 2005
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    For a hobbyist a 60 gallon single stage unit that puts out at least 12 cfm will get the job done. Would an industrial grade true 5 hp 80 gallon two stage unit that puts out 20 cfm work better ? Absolutely !

    An industrial grade single stage true 5 hp 80 gallon compressor would work just as well as 2 stage unit of similar statistics will in reality work just as well as a two stage unit for the type of work we do. I think where pro's or well experienced bodymen/painters recommend a two stage compressor over a single stage compressor is MOST (not all) single stage compressors are home owner cheap compressors. There are several downsides to homeowner 60 gallon 5 hp (actual 3hp) single stage units. The home owner single stage units are in most cases double to triple the compressor pump rpm which produces more heat which produces more water vapor that condenses in the air lines in the garage/shop. Most home depot, harbor freight, lowes type 60 gallon compressors are obviously built cheaper than industrial units and that electric motor running at 3,650 rpm puts added strain on an air pump that was built pretty cheap to start with. What that means in real world application is those homeowner type air compressors will self destruct in a small fraction of the time it takes to hurt an industrial compressor.

    Just to give you an idea of comparisons - You can buy a 60 gallon 5 hp (actual 3hp) single stage 12cfm compressor for less than $500. My Quincy 5 hp 80 gallon 2 stage air compressor replacement cost new right now is a little over $4,000. I bought my Quincy new is 1984 For $1800 and it has been used just about every day since 1984. NEVER a break down, never touched a wrench on it until about a year ago and that was preventive maintenance, not repairs. Needless to say a $500 compressor will last only a very small fraction of the time compared to a Quincy, Atlas Copco, Saylor Beall, high end Ingersoll Rand etc.

    Let's compare compressors to cars. If you plan on not driving much and all you want is bare bones basic transportation and all you can afford or justify is a Yugo then that car will get you to where you want to go as long as you don't drive too far or too often. It will do that until it breaks down and costs more to fix it than a new one costs. On the other hand a Chevy Malibu or Ford Fusion will last a lot longer and give you much better service all the way around compared to a Yugo.

    My honest suggestion is buy the best compressor you can afford, even if you have to borrow a little money to get it. You will never be sorry and you will never say "Gee, I wish I would have have bought that really cheap compressor instead of this good one".

    One last thing, a good used industrial air compressor is a much better choice than a new cheap air compressor. If you go to look at to buy a good used industrial air compressor, take someone with you that knows what to look for so you don't buy a bad compressor.

  3. #3
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    Feb 2006
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    Quote Originally Posted by A1980C3 View Post
    Okay, Iíve read a few, seems like millions, of posts on air compressor size. Do I need a dual stage compressor or a single stage compressor in my garage. My plans are for air tool use, not professionally, and occasionally some paint work. Can I get by with a 60 gallon single stage unit or do I need to fork out the money for a two stage unit.
    Thanks
    Really depends on what tools you want to use. Some are short burst like an impact wrench, these won't matter much with a 60 gallon tank. Its the more continuous operation ones like a DA, sandblasting, or a air hungry paint gun that tend to drive the need for the two stage. If you go single stage, do not get an oil-less compressor.

  4. #4
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    Len has mentioned that he has an industrial grade single stage air compressor. Autobody work really doesn't have a need for a two stage air compressor which are more efficient producing air as the air pressures go up. Most single stage compressors shut off around 130 PSI while most two stage compressors shut off between 160 -175 PSI. There is no air tool in an autobody repair shop that uses more than 100 psi so the single stage unit works just fine. It's honestly rare for me to see an industrial grade single stage air compressor because most commercial/industrial grade air compressors are two stage.

    People will argue that a 2 stage compressor holds more air reserve when it shuts off at 170 psi compared to a single stage unit shutting off a 130 psi. This is true but the two stage unit has to run longer to reach that 170 psi -- so what have you really gained ?

    Len, how many CFM is your single stage compressor ? Am i correct in assuming it produces around 18 - 20 CFM ? My point being for autobody use an air compressor that puts out 18 - 20 cfm doesn't really matter if it's single stage or two stage.

  5. #5
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    Quote Originally Posted by Phil V View Post
    Len has mentioned that he has an industrial grade single stage air compressor. Autobody work really doesn't have a need for a two stage air compressor which are more efficient producing air as the air pressures go up. Most single stage compressors shut off around 130 PSI while most two stage compressors shut off between 160 -175 PSI. There is no air tool in an autobody repair shop that uses more than 100 psi so the single stage unit works just fine. It's honestly rare for me to see an industrial grade single stage air compressor because most commercial/industrial grade air compressors are two stage.

    People will argue that a 2 stage compressor holds more air reserve when it shuts off at 170 psi compared to a single stage unit shutting off a 130 psi. This is true but the two stage unit has to run longer to reach that 170 psi -- so what have you really gained ?

    Len, how many CFM is your single stage compressor ? Am i correct in assuming it produces around 18 - 20 CFM ? My point being for autobody use an air compressor that puts out 18 - 20 cfm doesn't really matter if it's single stage or two stage.
    Mine puts out about 14CFM and runs up to 175 PSI before it shuts off. I've been using the same compressor for over 50 years and it still work great... knock on wood. I use it daily and change the oil about once a year.

  6. #6

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    People will argue that a 2 stage compressor holds more air reserve when it shuts off at 170 psi compared to a single stage unit shutting off a 130 psi. This is true but the two stage unit has to run longer to reach that 170 psi -- so what have you really gained ?
    Larger compressors need more cfm so a two stage is the way to get it. Other wise it would run a long time to get up to pressure. Larger compressors also usually can build more pressure. Don't confuse psi with cfm. I have two compressors a small single stage and and monster two stage Quincy. No comparing the two, I use the single stage for small stuff but if i need a lot of air i fire up the Quincy.

  7. #7

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    Quote Originally Posted by Len View Post
    Mine puts out about 14CFM and runs up to 175 PSI before it shuts off. I've been using the same compressor for over 50 years and it still work great... knock on wood. I use it daily and change the oil about once a year.
    Wow, that is impressive Len.

    50 years of service in a production shop environment is phenomenal, definitely got your moneyís worth on that machine!

    Maintenance is key, but so is having a good quality machine, as yours obviously is.

    Iím guessing a 2 stage pump from the 175 PSI shut off pressure?

    With that longevity and still running strong, sure would like to know what brand it is, care to share with us?

  8. #8
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    Feb 2006
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    I bought a well used shop compressor with bad bearings (worn out), 80 gallon tank with a recently replaced mag switch and original motor. Pump rebuild kit was double what I could get a replacement pump from Eaton. I bought a 3 cylinder pump rated for 7.5hp. I cleaned and painted the tank, and retrofit the new pump. That was 10 years ago, still going strong. It'll shut off while I'm pressure sandblasting, its a beast at 26 CFM @100psi. Also is setup for unloading so the motor doesn't shutoff - I've used that feature like 3 times. I set the switch for 175psi shut off. My brother-in-law still has my Sanborn 5hp 60gal single stage, I bought it in the early 90s.

    https://eatoncompressor.com/product/...specifications

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