Mating Problem!

Forums Air Tanks, Pumps, & Compressors Mating Problem!

  • Views : 296
  • Link

    moonlitnite
    Participant
    Member

    Gulp, I never envisioned that someday I'd be asking other grown men to help with a mating problem but I'm perplexed and need some good advice…

    Okay, I'm adding a Coalescing Filter the my Sieve Filter and am not getting a good seal on the fitting.  As best I can tell the male and female assemblies "should" mate together but I can hear a leak as I start to pressurize the filters.  I suppose I could get two Crescent wrenches and really crank down in a attempt to put extra friction on the "metal on metal" connection but I get the feeling I'm missing something here.

    I would appreciate your advice and counsel, Mate ;)

    Michael

    Link

    DirtyDovi
    Participant
    Member

    Thread-Gremlins always show up when you least expect them to..  

    Just like with nuts and bolts,  thread size and thread pitch must match 100%.
    A bit problem is – It is never that simple when dealing with fittings.

    In the US,  we use NPT as our standard.
    Outside of the US,  the rest of the world usually uses BSPP / BSPT

    They are not interchangeable.  Even though they are close..

    NPT will have more of an angled thread pitch – BSPP threads will be straighter.

    IF the fittings that you have aren't of the same type – Most likely that could be your issue.

    I've worked with hydraulic and pneumatic fittings a LOT over the years, 
    so I know what a  p.i.t.a.  this sort of thing can be.

    Don't force or over-tighten the fittings.  That can and will usually damage the threads.

    You can check the thread/pitch styles if you have other fittings that you KNOW are either NPT or BSPP.

    IF you've lucked out to the point that you can finger tighten the male into the female, 
    and they appear to 'fit', but just don't hold air – Well – There's a cheat to get them to hold pressure, 
    but it is very temporary, and really shouldn't be relied on.  It's not a 'fix'.

    Yellow Thread Tape.  Yellow tape has a bigger mil thickness compared to white tape, 
    so you'll get a much better seal with it.  It is usually used on gas lines / fittings.. 

    I actually use it on all of my threaded applications now – even if it isn't actually needed..

    The tape will fill the gaps in the threads very well.
    If you know that you don't have the right threads, but can get the tape on, and adapters assembled..
    Just tighten them in small increments at a time – as to be sure you're not getting them too tight..
    Check for air leaks.  Tighten a little.  Check for air leaks.

    Chances are – That's the issue. 
    Companies / People don't always use the same parts, so it's up to us as the end-users 
    to figure it out.

    Sam –
     

    Link

    Humdinger
    Participant
    Member

    Everthing in Sam's post above is true.  However, the type of fitting you have is none of the above and they are made to mate with each other.  They are a JIC female fitting on the coalescing filter to a JIC male connection on the hose.  They seal together by tightening only.  Chances are you've not wrenched them together tight enough to seal.  JIC fittings do not seal together by adding tape or sealants.  

    • This reply was modified 2 weeks ago by Humdinger.
    Link

    Joes41
    Participant
    Member

    This may be a silly question but can't you just eliminate that fitting and screw the hose directly to the canister like how it is on the one next to it? 

    Link

    BigTinBoat
    Participant
    Member

    Humdinger

    Everthing in Sam's post above is true.  However, it appears that the type of fitting you have is none of the above and they are made to mate with each other.  Those are  a JIC female fitting on the coalescing filter to a JIC maile connection on the hose.  They seal together by tightening only.  Chances are you've not wrenched them together tight enough to seal.  JIC fittings do not seal together by adding tape or sealants.  

    This right here. With a JIC fitting that last little 1/16 of a turn is usually what it takes to seal.

    Joes41 – hard to tell in pic but those JIC fitting are usually clamped on the hose via hydraulic press.

    Link

    acs
    Participant
    Member

    A JIC fitting is basically a high pressure flare fitting.

     In case you don't know about this type fitting, here is a tip…

    Looks like a burr on the fitting from the pic, but can't see it too clearly on my phone. Anyhow, best to check and clean, de-burr all threads/mating surfaces, lube threads/flare surfaces very very lightly with a non petroleum oil/grease (lightly is the key word here). The fittings should thread together easily by hand till the flares meet at almost the end of the threads, thats where the sealing happens. You need 2 wrenches that fit perfectly on the fittings, flare nut wrenches work best, but big adjustables will work. Once hand tightened all the way down then hold the stationary fitting firmly (maybe wrench against a hard stationary surface) from moving and then tighten down the fitting that spins. It needs to be very tight. Check it with a spray bottle of soap suds after it is pressurized, if it leaks tighten it some more. Do not use any Teflon tape, pipe dope, sealer, nothing at all on this type fitting. A good burr free lightly lubed fitting put together right will seal leak free for ever..

    jmo

    Link

    DirtyDovi
    Participant
    Member

    Thanks for the information and 'schooling' you guys!

    I'm pretty sure that this is the first time that I've seen what you're calling a JIC fitting.
    After giving it a second look,  I can see the convex section in the left hand connector, 
    and what you explained makes perfect sense how the two sections would lock together, seat, and seal.

    It's nice to learn something new!

    *Thumbs Up*

    Sam –

    Link

    moonlitnite
    Participant
    Member

    Awesome information gentlemen and it's helpful to learn that this is a normal JIC fitting.  As an aside for a moment, it's a ironic dichotomy how on one side we get seduced to buy a super-affordable compressor like the Yong Heng, only to later end up buying tons of "accessories" including supplemental filters, fittings, adapters, bleed valves, dead-heads, etc. No more teasing the love of our life about all the accessories they wear!  So buying an "aircraft grade" coalescing filter itself costs $145 itself – what's up with that?  But honey, the shipping is free and we don't want water and oil to contaminate my PCP gear, right?  Hmm – good luck with that argument.

    Back to the nuts and bolts discussion… as all our accessories pile up, it's a real memory game trying to figure out what piece parts came with what subsystems!  And doubly ironically, just after I made the post here, I received an email from ebay asking for positive feedback.  The email included a helpful photo that illustrated the said connectors are indeed meant to align and mate up together.  So as y'all pointed out, the JIC fittings are meant to fit together and I'll need to inspect for burrs, apply more pressure, etc. And in retrospect, the JIC fitting at the top is exactly the same and doesn't leak so I can do some comparisons and mix and match to see the source of the problem.  See the second photo in the series.  Then again, maybe all I need to do is wear white gloves like the person in the photo and my problems will be solved ;) 

    http://www.ebay.com/itm/30MPA-Pump-Water-Oil-Separator-Filtration-Air-Pump-Filter-for-Scuba-Diving/182913433901

    Thanks again for all your helpful feedback – Happy trails,   Michael

    Link

    moonlitnite
    Participant
    Member

    Okay all, I'm good to go.  Either removing the remnant teflon tape or giving the JIC fitting some extra elbow grease did the trick.  And in retrospect, I agree – wouldn't it be nice if all fittings mated so well ! 

    Link

    DirtyDovi
    Participant
    Member

    moonlitnite,  Glad to hear that you got everything sorted out, and that you're back in action!
    You sure do have a way with words, and I was cracking up while reading your post. 😁  

    As for the expense of the moisture-traps [oil/water separators]
    I found a much cheaper option, and am in the process of getting it all here and assembled..

    This is a similar high psi inline filter – just cotton plugs – nothing fancy.  
    https://www.ebay.com/itm/PCP-Air-Filter-Compressor-Oil-Water-Separator-High-Pressure-300bar-40Mpa-Pump/264111150482?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

    Here is some Molecular Seive – which will trap impurities / moisture much more efficiently:
    https://www.amazon.com/gp/product/B06Y2B4CPK/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1

    I'll be making a '5-chamber-setup' inside of the tube..  From side to side it will be:
    Cotton, then M.S. then Cotton, then M.S. then Cotton.
    [Unless I opt for cotton on the ends and M.S. in the center later on]

    I'm sure this will be just as effective, and at a fraction of the price..

    Sam –

    Link

    Humdinger
    Participant
    Member

    Sam’s $30 black filter has 1% of the moisture removal capacity of Michael’s coalescing water separator combined with his much larger capacity gold moisture filter.   With similar compressor setups  the black filter will have to be serviced frequently in comparison.  The black filter is fine with an adequate coalescing tower which Yong Heng class compressors compromise on. Dive compressors have them but they also have moisture filter towers too which makes an additional filter unnecessary.  Michael’s setup is most needed by the Yong Hang class of compressors which have undersized water separators. The first coalescing tower extracts  99% of the moisture before the moisture  filter has to absorb the remaining 1%. The dual process setup costs more but requires less servicing. A black filter on a Yong Heng class compressor working without a water coalescing tower catches all of the moisture and is quickly saturated regardless of how it’s packed.

    • This reply was modified 1 week ago by Humdinger.
Viewing 11 posts - 1 through 11 (of 11 total)

You must be logged in to reply to this topic.