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Best pipe for compressed air

Discussion in 'Off Topic' started by Modeler, Sep 19, 2013.

  1. Modeler

    Modeler Molalla, Oregon Soccer Fan

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    I've just purchased my first "big boy" air compressor, it's big enough to have a place in the garage and have it plumbed into a system but still small enough to wheel somewhere else on the property if needed. What's the best pipe to use for plumbing the air system? It'll be a small system, the pipe will go from the compressor vertically about 3', then turn 90 degrees to go through a wall and tee into an 18' pipe that will run the length of the garage with 3' vertical drops on either end and a tee to run back through the wall into the reloading room.

    I know PVC is out, I've heard steel pipe is good but it can rust (condensation is a concern in my detached, unheated garage). I've also read about using copper pipe, but I haven't worked with it much and I'm having trouble picturing how to terminate the end with threads that I can screw quick-connects onto.

    Anyone know about this stuff?
     
  2. Ben Beckerich

    Ben Beckerich NW Oregon Bronze Supporter Bronze Supporter

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    Copper... and it's actually sort of fun to put it together, when you're not working within the confines of the interior space of a wall or a crawl space under a house.

    You just need to find fittings with threads that match the pitch on your fittings... shouldn't be hard at all. I'm sure you could order them from any place that sells compressor parts.
     
  3. Ben Beckerich

    Ben Beckerich NW Oregon Bronze Supporter Bronze Supporter

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    female_adapter.jpg

    Something that looks a lot like this, but for the thread size and pitch of your air line fittings. Off the top of my head, I don't know what size.. but it's standard. Home Depot stuff.
     
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  4. U201491

    U201491 Well-Known Member

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    I assume you will be running about 60 to 125 psi.
    About anything works.
    Most use black pipe or even sweated copper pipe and fittings.
    It takes one H of a lot of pressure to burst pipe like that so no worries if that was your concern.
    You can even put in water traps for condensation if you think that will be a problem.
    Just make sure you seal whatever joints you go with (teflon tape or pipe compound). Its a pain when you have the compressor going on all the time from leaks.
    You can even just run air hose attached to the wall by U clips.
    Do whatever saves you money.
    Pressure mainly comes into play with larger volume vs pressures.
    Small cubics like pipe are not a problem until you get into serious high pressures, like filling scuba gear.You could use PVC in the lower pressures like 60 psi, but Probably not the best but cheap, just use the heavy wall stuff..
    I had a large shop and just used air hose to run air all over the shop. Keep the dia up according to the distance, just kind of like water hose principle.
    There is also a water drain valve at the lower part of the tank to drain occasionally, or there should be.
    Most of your air tools, nozzles, etc are going to be std 1/8, 1/4 or 3/8 Pipe threads.
     
  5. GFO

    GFO WaCo, Oregon Active Member

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    PVC pipe works, look for the stuff that is rated at 300psi. Its lighter, cheaper, and easier to tap into at a later date if you want to add more outlets. Know several places that use it, and have for many years.
     
  6. oknow

    oknow amboy wa. Well-Known Member

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    Schedual 40 works with no problem.
     
  7. jbett98

    jbett98 NW Oregon Bronze Supporter Bronze Supporter

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    Make sure you slightly slope any long horizontal runs downwards towards the outlets, so you don't collect moisture in the pipe.
    When using copper pipe, "L" type is normally installed. It has a thicker sidewall. Any plumbing supply house will stock it.

    For your threaded coupling ends, you need 90 degree drop ear reducing elbows. They have two screw holes to fasten them to the wall.

    Go on YouTube to watch how to solder rigid copper pipe. Very simple, cut pipe, ream inside of pipe, use a 4 in 1 pipe cleaning brush, apply flux to inside of female fitting and outside of male pipe, fit together, heat female fitting only, till flux starts to run and apply solder to the female fitting (opposite side of torch). Don't move pipe while still hot. Wipe off flux.
     
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  8. Redcap

    Redcap Lewis County, WA Well-Known Member

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    I use black iron if possible. PVC works too.
     
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  9. Mark W.

    Mark W. Silverton, OR Bronze Supporter Bronze Supporter

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    My shop has been plumbed with schedule 40 3/4" PVC for 25 years now my compressor runs 125PSI. I have maybe 10 places to connect to and 5 elbows and 3 Tee's
     
  10. JayDub

    JayDub I got your 6 Member

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    Ditto on the slope, but take your drops off on the top of your horizontal lateral not the bottom and then 180 them back down the wall that way moisture remains in the lateral and drains down towards the low end of it. And install a drip leg on the end of the sloped lateral, run a drop straight down and put a drain valve on it so you can blow it down as needed. You can get an 110V auto drain for about $80 and it will blow down the moisture using an adjustable timer, works great.

    In this climate if you use a lot of air you're gonna have a lot of moisture, especially in the winter and you don't want that in your air tools or especially in your reloading room! Also be sure and replace the little petcock valve on your receiver with a good drain valve and locate it such that it's convenient to blow it down on a regular basis so you don't rust the bottom of the receiver out.
     
  11. Modeler

    Modeler Molalla, Oregon Soccer Fan

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    Way ahead of ya! I had planned on sloping the line towards the compressor end and having a drip leg with a quarter-turn valve. I went out and looked everything over this evening, before I do the air line I need to replace the wall paneling with plywood. While I have the wall opened up I might as well wire in some new 110v outlets, run a dedicated circuit for the compressor and put the welder outlet inside the wall (it's currently outside the wall encased in conduit) and insulate the whole thing. So it'll be a little while before I get to the air line I guess :rolleyes:
     
  12. Provincial

    Provincial Near Salem, OR Well-Known Member

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    In Western Oregon it is a good idea to have a good long length (or a "coil" to confine the long pipe into a smaller space) of metal piping/tubing where the line leaves the tank in order to condense as much moisture as possible out of the air. Plastic pipe isn't as effective for this, and it also should not be exposed to the hotter air because it rapidly loses strength as it heats up.

    Another problem with plastic pipe is that it is very sensitive to impact when pressurized. I just exploded a PVC pipe that had water at 40 psi in it by bumping it with a digging tool (not a hard impact, but a glancing blow), and it shattered and threw shrapnel several feet. I saw the damage when a 3/4" PVC Schedule 40 water pipe exploded with 150 psi of air pressure, fortunately when no one was around. It filled a 12x20 foot shop with shrapnel and broke the bulbs from two 8-foot florescent fixtures (and broke a couple of the bulb holders) making a mess of the whole place.

    I put at least 6" drops with drain valves at each point I connect a hose (outlet) and find water in all of them at some point. The further from the compressor, the less water. I have a mixture of black iron and galvanized pipe and don't have any problems with rust, but then I capture the water and pull it out in places that it doesn't sit in the part of the piping that is carrying the air flow.

    You will really be glad you made the updates you are describing. Compressed air is very handy to have available close at hand! :thumbup:
     
  13. moncon

    moncon willamette valley oregon Member

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    Pvc pipe is fine for air. If you are worried use schedule 80 pipe, more expensive but almost indestructible, its made for high pressure. Also put in a water separator and or filter, it will keep most of the water from entering the lines, and drain tank on compressor after heavy use.
     
  14. Kevinkris

    Kevinkris Aloha Well-Known Member

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    plus 1 here.

    ive helped (and i stress "helped") put in some compressed air lines with both pvc and copper lines and the pvc was much more forgiving with mistakes. i understand copper to be better for longevity though. probably important to remind you as GFO did and say be sure it is pressure rated.
     
  15. notazombie

    notazombie Hillsboro Well-Known Member

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    I've run schedule 40 at 120psi for many, many years with no problems. Like everyone else, I strongly recommend some sort of slope and a drain. An auto drain at the compressor is a nice option. I use one in my paint shop and never have any moisture issues. Nothing wrong with rubber hose either. It's cheap and easy to work with.
     
  16. 20buellteam

    20buellteam Near van mall Member

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    Your first instinct to avoid PVC is correct. And yes I know some who have gotten away with using it. But as Provincial pointed out, it shattered on him and that's why no licensed mechanical fitter or plumber will use it or hope to get it to passed a building inspector. There is plastic pipe designed just for compressed air but it is expensive, never rust though. Ferguson sells it I believe. Won't find it at Home Depot or Lowes. Good USA made heavy hose would be my choice. Blow down your tank every couple weeks to drain off the condensate.
     
  17. Modeler

    Modeler Molalla, Oregon Soccer Fan

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  18. Ben Beckerich

    Ben Beckerich NW Oregon Bronze Supporter Bronze Supporter

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    All I've ever seen in industrial use is copper
     
  19. U201491

    U201491 Well-Known Member

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    Copper is expensive in a large shop.
    Just good air hose with T's and drops around the shop works very well and doesn't break the bank. Easy to move when you need to also. No corrosion worries and pretty much maintenance free other than draining the tank regularly.
    There will be a petcock to open for a few seconds once a week and thats it, unless you need really dry air, in which case you can put an air dryer inline.
     
  20. tanzuki

    tanzuki Salem Active Member

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    Sch 80 for me for about 10 yrs. I know they say it's not recommended but it's for a home shop, it's inexpensive, and it works for alot of people so it should work for me too.