Air compressor for blasting recommendations

Discussion in 'Gun Project Questions & Gunsmithing' started by Spotshooter, Jun 23, 2019.

  1. Ksracer

    Ksracer

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    "There are two types of compressors. Single stage and two stage. The two stage compressor pumps air on both the down stroke and the up stroke and will keep the air pressure at a more constant level. In theory this will produce twice the amount of air as the single stage unit."

    Not really. Single stage compressors put the air from each piston into the tank, and are generally limited to 110psi. Even if they have two pistons, each one pumps into the tank individualy. Two stage pumps compress the air in the first piston to ~80psi, then cool it, and compress it again in the second stage piston to a higher pressure, usually 175psi max or so. They may be 2, 3, 4 or more cylinders, working together in several different configurations and flow paths.
    The only compressors that I'm aware of that pump on both strokes are massive horizontal industrial units built prior to 1970. They require a crosshead and a piston rod sealed with packing to obtain the second stroke.
     
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  2. Nick Caprinolo

    Nick Caprinolo Gold $$ Contributor

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    You are right of course. Thanks for correcting me.
    Nick
     
  3. Ksracer

    Ksracer

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    On the larger belt driven pumps operating at lower rpm's, a lot of the noise comes from the intake pulses as the air is drawn into the pump. They are usually fitted with small air filters that somewhat double as silencers. A good portion of the noise can be reduced by using a larger silencer, or plumbing the inlet to the outdoors using large diameter piping. If you build an enclosure around one to reduce the noise level, make sure you allow for plenty of air to get in. If you seal it to tightly, the intake pulses will make the walls vibrate like a speaker or a drum, and you won't get as much noise reduction as you otherwise could.
     
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  4. NV_Dmax

    NV_Dmax Gold $$ Contributor

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    I owned my own Cerakote shop and did many, many hours (years worth) blasting and painted a metric shit ton of guns and parts. That being said, I needed clean, dry air and lots of it. I really could have used 55cfm but could never afford it. In hindsight, had I had that kind of capacity, I probably would have reduced my working hours substantially.

    All i can say is buy once cry once. Get a Gardner-Denver rotary or scroll I would shoot for 65-100cfm, mount a cycling (unless you’re a 24hr shop then get a non cycling) drier far enough downstream to actually work, and put in a storage/expansion tank. In your shop install plenty of drops and coalescing filters at each. Use copper line and make sure it’s big. That’s enough to allow a serious amount of efficient blasting and expansion if you ever decide to do some automation.

    If you’re going to be occasionally blasting a pistol or rifle here and there; get a Quincy with a tank already mounted (that’s what I have) an air drier to match and some coalescing filters. Mount the compressor in a small enclosure outside and run the air drier inside the shop. Still run everything in copper. I beat the piss out that Quincy and it still ran fine when I closed up shop.
     
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  5. Intheshop

    Intheshop Silver $$ Contributor

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    Cpl things to look into..... going along with ksracer,look up a Helmholtz style resonater. Interesting reading,and not too hard to fabricate. And then for some more reading,look up a "franzinator"... it's an expansion chamber that gets plumbed between compressor head... and the tank. Ours is even water cooled. Ole mr Franz didn't invent it..... Google images of old Saylor Beale compressors. They came with finned aluminum expansion chambers 75 years ago.

    Franz has his story....and it's filled with drama. His approach was sorta flipping off the industry. Which sort of dances around the notion that the general public is too stupid to drain the main tank on a compressor.... so having to drain an expansion chamber too?

    On my 60g two stage,it has a custom intake and a water cooled expansion chamber.... I forget the numbers but shooting before and after temps on the affected plumbing saw a temp reduction of 50 degrees. And the moisture/mayonnaise from the head never makes it too the main tank. The water cooling is a total loss system....just tee off any cold water line. I run it into a bucket,set to a dribble.



     
  6. Dusty Stevens

    Dusty Stevens COVFEFE- Thread Derail Crew Gold $$ Contributor

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    Yall have really got to get out more. Id be willing to bet less than .1% of home shops have a screw type compressor with receiving tank. A 60 gallon 5hp model will do more than most any shop needs. I blast and even arc gouge with mine. Sure it may be slower than a $25,000 screw compressor but ill make it just fine. Harbor freight has a 25% off sale today and 20% off tomorrow
     
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  7. Hino895

    Hino895 Silver $$ Contributor

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    I use a 5hp Campbell hausfield for my cabinet.
    Bought at tractor supply 6 years ago, Cerakote a dozen or so guns a month.
    Change the oil religiously using mobile 1 and a addictive called motorkote.
    Zero problems and still using the original belt.
     
  8. Rustystud

    Rustystud Site $$ Sponsor

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    I upgraded on compressor number 3. 5hp, 80 gallon tank, 145 psi instead 125 psi, 18 cfm. I run a 36" drizzly cabinet. Much improved over my 3 hp 6 com 125psi cabinet.
     
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  9. Spotshooter

    Spotshooter

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    A screw compressor is way more than I need, and want to spend.

    9/10 I’ll go with Tractor supply and get an ingersol rand 80 gallon 2 stage... all good.
     
  10. Ares

    Ares

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    If noise was the bigest concern there are reasonably priced magnetic compressors that are really suprisingly quiet available these days.
     
  11. Dusty Stevens

    Dusty Stevens COVFEFE- Thread Derail Crew Gold $$ Contributor

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    Harbor freight has one on display at my local store that you have to almost put your hand on to hear run but its a small 2 tank nail gun portable type compressor
     
  12. Mudcat

    Mudcat Gold $$ Contributor

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    You will be happy. Try to catch them on sale, I did and save a couple hundred bucks.
     

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