Announcement

Collapse
No announcement yet.

Best thread sealant for compressed air fittings

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Best thread sealant for compressed air fittings

    I'm interconnecting air filters, regulators, hoses, etc. Some of the connections leak and nothing I use works. I tried teflon tape and different kinds of pipe dope from Home Depot. The worst connections are between brass males and female threads in the bodies of some filters and HF butterfly wrench. The bodies are made of different types of light metal, and the threads strip easily (not only on the chinese pot metal, but also in filter bodies that are made in Japan). I tried light torque and higher torque, and nothing helps. I'm almost ready to use epoxy adhesive on some of the connectors.

    I never had so many problems with leaking fittings before. I always buy the simple ones in Home Depot, Lowes, Menards and HF. Should I blame the ever dropping chinese quality of the threads?

    What do you recommend?

    P.S. I installed a lot of quick disconnects. Their behavior is not stable either: when engaged, the connections might start leaking and I have to shake them a bit. The females, in general, hold the pressure well, but then suddenly may start leaking, and I have to push a male in and out to make the female valve shut. Should I just throw away the chinese connectors and look for "made in the US" fittings? Are they still made in the US, at all? Or, maybe, I should minimize use of quick disconnects?

    It's so frustrating!
    Last edited by MichaelP; 09-05-2010, 11:30 PM.
    Mike
    WI/IL border, USA

  • #2
    The best sealant I have found is a loctite product, comes in what looks like a huge chapstick dispenser.

    I try to buy name brand fittings whenever I can (Nitto). I have had the same experience with the cheap ones. Beats me how they can screw up something with no moving parts.

    On Edit: The part number is: Loctite PST 561
    Last edited by Greg Q; 09-05-2010, 11:21 PM.

    Comment


    • #3
      Michael, I've had similar problems with junk fittings. I use Permatex 'SuperBlue' silicone and haven't had a leak since. Fittings sealed with this compound are also very easy to undo. The single downside is that you might have to give the joint a few hours before applying pressure if the leak is fairly large. The stuff used to be part #778, but it has a new number now. I think both are currently on the tube.

      I've not found any generic chinese quick-couplers worth keeping. They vary greatly from lot to lot. I have had nothing but great performance from Milton branded products so if you can find those I'd recommend them. I can't say for sure where they're made nowadays.
      Last edited by chipmaker4130; 09-05-2010, 11:04 PM.
      Southwest Utah

      Comment


      • #4
        Milton off-shored a lot of their production a few years back. Ironically, that was the same time that Northern Tool raised the price on their quick connects. They used to be pretty reasonably competitive with the chicom stuff, now they're at least 3x the cost (but still worth it).

        Comment


        • #5
          thread sealant

          For tough jobs I use gasoila red hard set I don't like silicones because of possible paint problems ,fish eyes don't look good in a custom paint job .

          Comment


          • #6
            Loctite 567,clean the threads with a tap and die,apply the 567 and screw together.
            I just need one more tool,just one!

            Comment


            • #7
              This is what I use.

              http://www.amazon.com/Pipe-Joint-Com.../dp/B000KKVWL6

              I quit using teflon tape long ago.

              Comment


              • #8
                Good product almost sounds like a proctology product




                I think this is essentially the same stuff as the previous post. Used it on water,air, gas lines forever.

                Comment


                • #9
                  Chipmaker, is this the one you have: http://www.jcwhitney.com/jcwhitney/p...8926G_CL_1.jpg ?

                  Wierdscience, when you use Loctite 567, how soon after tightening can you apply full air pressure? Immediately? Even if the leak was significant?
                  Mike
                  WI/IL border, USA

                  Comment


                  • #10
                    thread sealer

                    use aviation form-a-gasket#1 or #3 from the auto parts store. its that dark brown ,black goo, thick as chassis grease stuff works great for me, seals every thing up, never a leak on my engines.i hate silicon, it hardens into little pieces, and then travels into some place it shouldnt be.(oil passages ,valve lifters)
                    Last edited by madokie; 09-06-2010, 04:25 AM.
                    FORD BEATING JAP CRAP SINCE 1941!! CAROLYN JONES(1930-1983 actress)may this lady never be forgotten.

                    Comment


                    • #11
                      Nitto

                      I use all "Nitto" fittings and have only had to use teflon tape - never a problem. It is "soft" and screws on/in easily and can be used immediately. If it leaks first time I either put more teflon tape on the existing or more likely pull all the old teflon off and re-start with more turns of telflon tape on the male screw.

                      When it comes to unscrewing the joint, it is dead easy and no bits of jointing etc. getting where they shouldn't be - and they leave a nice joint to re-use without and further preparation or cleaning.

                      I have never had a threaded joint failure in a Chinese tool - or any others either.

                      If I do have a leak it is nearly always caused by me pulling the hose side-ways at the joint - so that's my fault - not the joint's.

                      Comment


                      • #12
                        Originally posted by MichaelP
                        Chipmaker, is this the one you have: http://www.jcwhitney.com/jcwhitney/p...8926G_CL_1.jpg ?

                        Wierdscience, when you use Loctite 567, how soon after tightening can you apply full air pressure? Immediately? Even if the leak was significant?
                        Not immediately,it really needs 24 hours to cure fully even with activator.If your putting in a system that's not too bad.I use it because it covers pretty much everything including steam up to 400*.The cure rate is 30min-24hours and the max pressure is 10,000psi.Technically according to the charts it's at 20% of it's 10,000psi strength at 30minutes,but material and temperature come into play.

                        564 cures in five minutes,good for 10,000psi and 300*F,probably the one for repair work/quick assembly.

                        561 Stick is new on the market,I haven't tried it yet,but the salesman says it's great.

                        As with all Loctite products you may or may not need an activator on non-ferrous fittings.

                        http://useloctite.com/products/produ...ealing4c67.php
                        I just need one more tool,just one!

                        Comment


                        • #13
                          OK, thank you.

                          BY the way, I found a nice Loctite Product Guide: http://thirdshift.nu/portfolio/v3/pdf/mro_catalog.pdf
                          Mike
                          WI/IL border, USA

                          Comment


                          • #14
                            It sounds to me like far too many problems if you are doing things right. I suspect either cheap fittings or mismatched thread styles. Compression fittings should not need any sealant unless they are damaged.

                            I would be concerned with the use of inexpensive components from a variety of sources. Also, Home Depot, Lowes, etc. do not provide the best advice when purchasing matching fittings. Their personnel are hired on the cheap, not for their experience. Many DIFFERENT style fittings have very similar threads. If you attempt to use a male thread of one style with a female of another, it may actually "fit" but getting it to stop leaking will be all but impossible and both may be damaged from the attempt. Even if you put enough sealer or epoxy or whatever to get it initially sealed, it may very well leak later.

                            Do go to a real hardware store. One that has been there for 25 to 50 years and talk to the people in the plumbing department. They will be much more useful in matching the various fittings. Do not just assume that if a thread "fits" that it is a proper fit.

                            If you need some fittings or devices that the local hardward does not have, McMaster is an excellent web source and you can count on the quality being OK. Auto parts stores can also be an excellent source for some kinds of fittings. But again, be sure that the thread you are buying is a proper match for the thread you have.

                            With good quality, matching components you should have little or no need of sealants except for tradational, tapered threaded pipe fittings.
                            Paul A.
                            SE Texas

                            And if you look REAL close at an analog signal,
                            You will find that it has discrete steps.

                            Comment


                            • #15
                              Paul, fortunately (or unfortunately?) the big box stores do not have enough variety of air fittings to be confusing. The leaking joints are all 1/4" NPT (but not all 1/4" NPT joints are leaking, of course).
                              Mike
                              WI/IL border, USA

                              Comment

                              Working...
                              X