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Black Iron pipe airlines

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  • Black Iron pipe airlines

    I am getting ready to install black iron pipe air lines in my garage shop.
    Home Depot has it already threaded.
    I have about 61 feet inside the shop. I also have to run hose outside to air up tires and occasionally use air tools outside.

    TP Tools suggests 1/2 in, up to 75 ft.
    Should I use 1/2 in, or 3/4?

    Do I need to include the outside hose in the equation?

  • #2
    The demand of your tool (s) is what dictates the pipe size, the length of pipe will have an effect but not much at that length.

    ...Galvanised pipe would be more suitable for your air system.
    " you not think you have enough machines?"


    • #3
      How deep are your pockets? 3/4" allows for future air CFM increase. It will take longer to pressurize the system, however the compressor will cycle less often. It will also cool the air allowing moisture traps to do their thing. If you're short on cash, then 1/2" is the cats PJ's.


      • #4
        I also recommend 3/4" black iron pipe in order to allow for future expansion. That's what I used. Now, I wish I had gone larger because I get a significant pressure drop out at the end of the line.

        I've been told that galvanized should not be used because the zinc will release flakes and "hairs" that could cause trouble in pneumatic equipment.

        I've never had any trouble from rust in my lines. When I blow out the condensate in the lines I get a little reddish color; but, the moisture also seems to capture the rust and prevent it from causing any problems.


        So many projects. So little time.


        • #5
          Put a good water/moisture trap on the outlet of your compressor, and use the 3/4" black iron, as the flakes and other things from inside the galvanized pipe. If you have a couple drain line pet cocks on the runs and blow it down when you start it up or if it isn't used daily open them up and leave them open between uses. Had 150 feet of black iron pipe in the tunnel to the boiler room from the fanroom where the air compressors were. drains on both ends and never had any trouble.
          Been there, probably broke it, doing that!
          I am not a lawyer, and never played one on TV!
          All the usual and standard disclaimers apply. Do not try this at home, use only as directed, No warranties express or implied, for the intended use or the suggested uses, Wear safety glasses, closed course, professionals only


          • #6
            Have you used any pre-cut pipe from the box stores lately? The last pieces I bought had threads that were at an angle to the pipe axis, wouldn't seal no matter how tight I got them, or both. If you have liberal tolerances for alignment and love pipe dope, you'll probably be OK.

            Any products mentioned in my posts have been endorsed by their manufacturer.


            • #7
              Sorry but when I saw the title I was expecting a new airline business that was in operation, Maybe flights to the tarsands in Alberta?

              Sorry for the dry humor, Use 3/4 on top of the above reasons it gives you a larger air reservoir of air plus larger pipe then more cooling surface, More money but overall a better system.



              • #8
                Thanks, I figured it would be better to go with 3/4.
                I currently have that white stuff, for my airlines and want to replace it.
                I have dump valves at each air chuck (I only have 3 chucks) and will have another one adjacent to the compressor, maybe even exiting outside.


                • #9
                  1/2 inch is more than adequate unless you plan on using a sandblaster @ 100psi with a 1/8 tip and the cfm to go with it and of course the huge amperage to drive it. Most of the iron pipe installs I’ve seen have been black. Agree, install a moisture separator, post compressor pre line assembly.

                  Cheers, Bob


                  • #10
                    A good friend and I built our airlines together on a long weekend several years ago. He used 3/4" black pipe, and I used 3/4" copper (this was back before copper cost more than titanium). As far as the installation goes, the black pipe was a pain to get air tight (so the compressor wasn't cycling): we used tape, but pipe dope might have been easier. You also get completely covered in that black sh!t (paint or tar or whatever it is). The copper pipe we had to solder, of course, so I think the net total work (black or copper pipe) was about the same.

                    We're over at each other's shops all the time and honestly, after the install, neither of us can tell any difference in performance between the two, including the amount of moisture at the outlets.

                    We followed this Sharpe diagram almost exactly, except I was really short on lateral space, so I had to coil 50 feet of copper pipe to fit on the garage wall above the compressor (the "Still" as some people here have called it) and I left out the u-shaped drip-loops at the air drop tees, since I don't have space for a dead leg. Sharpe recommends a minimum of 3/4":

                    A much bigger diagram in .PDF is here:

                    "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."


                    • #11
                      Why not use high pressure polythene pipe??
                      Precision takes time.


                      • #12
                        So, which of the 2 from Sharpe, the one with the riser drip, or without--they show both diagrams?

                        Is this a better method than the one from TP Tools?


                        I just bought a manual pipe threader for $7 at an estate sale--a #10A Craftsman-was that a waste of spare change?


                        • #13
                          Originally posted by ligito
                          So, which of the 2 from Sharpe, the one with the riser drip, or without--they show both diagrams?
                          I didn't build the drip loops -- its pointless if you don't have a dead leg, and I didn't have the wall space for it.
                          "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."


                          • #14
                            I did 1" primary black pipe with no drain grade other than the natural drop of the building. Due to height issues with my bridge crane, I didn't do the vertical risers off the primary either (I wanted to, but space wasn't there for it). The system has been in use for about a year and a half now, and I have very little water in any of the 6 drops. I use it all the time, but I only run around with the purge bucket every 6 mo's now because I rarely have anything come out. I've got a high flow (125cfm) coalescing filter on the other side of the tank shut off valve before being fed to the pipes. I do get a lot of moisture in the tank (80gal), so there's not much left once it leaves.

                            The reason for the 1" primary is that I have 100cfm at the farthest end of the system without it being in a loop (something you might consider depending how much air you think you'll use). I wanted that volume available in the event I wanted to blast something in the driveway - which is an 80' run from the pump to the front garage wall. The price difference for going up another size isn't all that much. All my drops are 1/2".

                            Check pipe pricing at the steel yard for 24'er's before you spend money on the box store stuff. Sadly, lowes had better quality chinese pipe than any of the yards did here (all rusty). I made them price match HD with every purchase and it worked out. With the current state of fittings supply - pipe dope is your best friend. 90% chance you won't be able to find US made fittings even if your pipe comes from us.


                            • #15
                              I have a 10 ft run from my compressor to the next T that runs across the shop ceiling to the opposite side, for a drop my air lift, then continuing toward the door for another drop.

                              So you're saying that I don't really need risers?
                              I can just drop straight down from the T?

                              I don't understand how a loop is used, or placed, after the compressor.
                              I do have room on my wall, if I need to hang some form of loop but don't know what it should look like.