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Gas Piping - teflon tape

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dfru
dfru Member Posts: 27
I was recently inspecting a project and found that the threaded pipe joints are sealed with white teflon tape, rather than approved yellow tape. I have heard of one plumbing inspector requiring gas piping systems which are installed as such to be ripped out entirely. Has anyone experienced this? Are there any repairs which could be done which would allow the existing system to remain intact?



Any thoughts would be much appreciated.
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Comments

  • RobG
    RobG Member Posts: 1,850
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    Not shure

    I'm in Virginia and have never had an inspector stipulate what I use to seal the joints. As long as it passes a pressure test it should be OK. With the quality of pipe and fitting manufacturing these days I prefer to use both tape and dope to fill the voids.



    Rob
  • gennady
    gennady Member Posts: 839
    edited August 2014
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    Pro dope.

    Gas line must be done with pro dope. And nothing else. No Teflon tape on gas line will pass NYC inspection



    403.9.3 Thread compounds. Thread (joint) compounds (pipe dope) shall be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be conducted through the piping. Use of cotton thread (lamp wick) is prohibited.

    403.10 Metallic piping joints and fittings. The type of piping joint used shall be suitable for the pressure-temperature conditions and shall be selected giving consideration to joint tightness and mechanical strength under the service conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
    STEVEusaPApipers
  • RobG
    RobG Member Posts: 1,850
    edited August 2014
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    Must Be?

    I saw nothing in the code that you posted that said it MUST be Pro-Dope, are you an Oatey/Hercules rep?. It simply says that it can't be LP soluble or lamp wick (which bothers me a little because I use lamp wick all the time) :) .



    I actually just looked up Pro-Dope (I don't use it). I love the description:
    • Oil-based thread sealant.
    • Not for use on plastic pipe or fittings.
    • Gray color.
    • Non-setting formula; will not harden, crack or become brittle.
    • Accepted for use on FlowGuard Gold® pipe and fittings
    • If it's not for use on plastic, how come it can be used on CPVC?



      Rob
    STEVEusaPA
  • jonny88
    jonny88 Member Posts: 1,139
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    with Gennady

    I only use pro dope on gas.I think like Gennady in NYC the majority of plumbers i have come across use pro dope.No bragging but I have used it on 4" pipe down to 1/2 inch.Look up Gennadys profile you will see he is no rep take a look at his work.I know guys who use blue bloc but I dont like it as is hardens and can crack if your not careful.Pro dope doenst harden thats why I like it and so far I have never had a problem.Thats not to say I havent had leaks usually down to my own fault but the product is my preference.From day one we were told no teflon on gas period and it stuck with me.But everyone has there preference.

    You could start the same thread with solder,flux etc whatever works.
  • RobG
    RobG Member Posts: 1,850
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    Not to offend

    I didn't mean to offend, I was just stating that there is no ONE product for everyone. I grew up with Permatex Black and that's what I still use. I won't say that I've never had a leak, but any leak that I've had has never been because of the pipe joint compound.  (it is messy and smelly, my wife won't touch me until it is off my hands, sometimes it takes days :)





    Rob
  • gennady
    gennady Member Posts: 839
    edited August 2014
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    Pro dope

    The nature of treaded joint is fusion of molecules of joining metals. When treaded joint is made , great pressure is created between fitting and pipe tread. All we need is lubrication and polishing of joining surfaces. This is a pro dope. Mixture of oil and polishing particles. It is similar to welding. Anything in between joining surfaces only does harm.
  • Bob Harper
    Bob Harper Member Posts: 1,049
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    PTFE allowed?

    Both the NFPA 54 NFGC and the IFGC allow PTFE tape for gas threaded connections. The attached line from the NYC code does not prohibit such tapes either. This is an interpretation issue. The white vs. yellow PTFE tapes has nothing to do with the gas itself but simply thickness. The yellow is thicker. You can use Blue Monster tape if you want to. I personally do not believe in using any sort of tape or wicking because I've seen and investigated too many valve failures caused by pieces of tape getting into the gas stream and partially clogging a valve seat. The code cannot specify one brand---that's a monopoly. They can specify certain properties or compliance with a national standard but otherwise your inspectors are full of BS. The biggest problem with PTFE tapes is the danger of over-tightening. They lubricate the joints so well you run the risk of cracking the female hub since NPT is tapered. Unless you have another more specific local ordinance, the one provided merely reflects the two major model gas codes. I personally use the blue goos here lately but most PTFE dopes, Rectorseal #5, etc. are all legal. I think the inspector is the dope here. If the dope is compatible with NG and LP, it's legal-done. More important fish to fry such as improper support or testing the joints.
    ChrisJ
  • icesailor
    icesailor Member Posts: 7,265
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    Pipe lubes:

    Thread sealing compounds are just like lube oil in an engine. It is to fill the microscopic spaces between one metal surface and another. Theoretically, you don't need ANY compound. But in the process of tightening up a fitting and "galling" occurs, you will have a leak.

    As far as the color, some AHJ board lobbied to make people use colored tape. What's the difference between the old standard white, the blue that Crest Good sold and the new Blue Monster stuff they sell today? What's with the Pink stuff that they sell at HD and Lowe's? Where are you supposed to use that?

    Teflon tape alone is equal of better than any pipe dope used alone. Used together, it has no equal for thread sealing. "Pipe dope" is for union faces on ground joint connections.



    Old dinosaurs lobby Code Writing Authorities to outlaw their pet peeve latest improvement. Onward, backward and downward in reverse.

    I've used Teflon Tape for over 40 years exclusively. If it didn't work, I wouldn't use it. Teflon tape on gas? I was once doing a boiler when a gas fitter was piping the building. He had a leak when testing near where I was working. After two attempts at fixing it, I told him to use some tape. "Junk, absolute garbage. I would never use it. It doesn't do anything but make leaks". After two more tries to stop the leak, (this is over a 5 day period), I got PO'ed and fixed it myself, with tape. The next day, he bragged to me how he didn't need no stinking tape. Little did he know.



    Tape on oil? Rectorseal #5, Gasoila, Blue Mol is so nasty that if you get it on your clothes, its there forever. Get it in your hands, hand cleaner won't remove it. OK for oil pumps, but not tape? Another air cause.
  • icesailor
    icesailor Member Posts: 7,265
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    Improperly applied tape connections:

    If you find strings of tape inside valves and fittings, the tape was improperly applied. If you find strings inside, the tape was started beyond the first thread. It needs to be started in the second thread back. If you are piping 1/2" to 2" pipe, it only has a 1/2" make-in. If you go to the end of the thread cut, you are wasting tape.
  • RobG
    RobG Member Posts: 1,850
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    Who uses what?

    Who uses what and why for gas pipe sealant



    I use black Permatex because that is what I was taught with and I've never had a problem with it (except getting on my hands).
  • hot_rod
    hot_rod Member Posts: 22,476
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    the current tapes

    are a big improvement. I believe Mill Rose has 3 or 4 colors now, even a special tape for stainless steel. No more throwing away 1/2 a roll because it refuses to unwind. The thicker tapes work down to the last inch on the roll.



    If there are shards of tape inside the pipe, it's "operater error" as Ice mentioned.



    It's nice to go home at the end of the job without a layer of pipe dope on you and your tools and clothes.



    If you are splitting joints with teflon tape, time to buy some shorter wrenches :)



    Anymore a good channelocks type pliers, Knipex, for example is all you need to work up to 1" threaded pipe, if you use teflon tape.



    Just because a local AHJ prefers or requires you to use specific method... but that is your battle to fight. Or not.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Tom_133
    Tom_133 Member Posts: 891
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    Our Local Natural Gas Company...

    doesn't want teflon on any gas pipe unless its yellow. They say in some scenarios excess internal teflon in the pipe can find its way into the gas valve not allowing it to close. I don't fully agree but I follow along with their preference so I don't get a verbal lashing, and while thoroughly ravaged, have to redo it.



    I use gasoila, never heard of pro dope will look for it next time.
    Tom
    Montpelier Vt
    Big_BurnerLyle {pheloa} Carter
  • gennady
    gennady Member Posts: 839
    edited August 2014
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    Gas piping

    Gas piping installation is regulated by NYC fuel gas code. Pipe dope is listed, Teflon tape is not. Code is permissible . It means it allows listed materials and methods. If method is not listed, it is not allowed. I'm following code to the letter when I do our installations in NYC.
  • j a_2
    j a_2 Member Posts: 1,801
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    Pipe Dope

    Any of the honeywell gas control valves I have installed, the instruction manual says DO NOT USE TEFLON TAPE….They also say no sealant on first two threads…..Makes sense to me……They also spec. how far they want that nipple installed,as not to damage the gas valve body….
  • icesailor
    icesailor Member Posts: 7,265
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    Some People:

    Some people paste both male and female sides of the connection rather than use tape. I've seen Rectorseal #5 run all over the inside of the valve. Excessive use of paste is just bad practice.

    Manufacturers use any excuse to deny a claim. A bad coil on a solenoid valve has nothing to do with the use of tape. But they will stick you with the valve if they find tape. Properly applied, there won't be any.
  • Steamhead
    Steamhead Member Posts: 17,008
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    In Baltimore

    inspectors do not allow Teflon tape on gas piping. Doesn't matter that NFPA 54 doesn't specifically prohibit it- they will not pass a job with taped joints. Many contractors sidestep this by using CSST- we do not, for reasons we've discussed before.



    If we see gas piping with Teflon tape, we know it was probably a DIY job.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • icesailor
    icesailor Member Posts: 7,265
    edited August 2014
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    Has Beens:

    I'm sure that they do and I'm sure that someone had it declared illegal.Done by a bunch of old has-beens that that don't want anything to change. If it were up to them, we'd still be using cast iron drainage pipe with lead and oakum joints. They almost dies when Gasketed soil pipe was approved. Then, No Hob clamps came along. The #1 argument was that some child could take a 5/16" nut driver and dismantle the sewer system. There was nothing better than lead water services. Properly code sized sanitary waste lines are too big for low flush toilets. There isn't enough water to flush a line. So if a gas leak develops after inspection and put into service, that would have never leaked if tape had been used, and the leak causes a fire or explosion, it will never be blamed on not using tape. You can use a #430 Channel Lock pliers in 1/2" gas pipe and never have a leak of over tighten it. I've taken 1/2" and 3/4" gas pipe that I swore was tightened with a 24" pipe wrench. Sometimes, that's what it took to get it apart.



    Its probably a union thing. Its easier and quicker. Anything that saves time is a No-No.
  • Steamhead
    Steamhead Member Posts: 17,008
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    I'm sure they have their reasons, Icy

    but we have to comply. 
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • RobG
    RobG Member Posts: 1,850
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    What is?

    What is the correct torque for gas piping? It was never covered in my trade school classes. besides that you want to make it tight and then turn to the position you need it to be. Never turn it backwards. I have turned some fittings slightly back when I knew that another full rotation would probably crack the fitting but I always felt that with the right pipe sealant it was not a problem (knock on wood).Once again, I use black Permatex.



    Rob
  • jonny88
    jonny88 Member Posts: 1,139
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    black permatex

    I liked your comment with the black permatex.I come out worse if I use bluebloc.As for silicone it should not be put near my hands.Another reason I like pro dope is that it doesnt spill or harden so if you have to back of a little bit the joint should not crack even though I hate to do it.On a side note in the last three weeks I have had sand holes in two1inch galv ward tees.Am i the only one.
  • gennady
    gennady Member Posts: 839
    edited August 2014
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    Interpretation.

    Sure. There is no Teflon tape allowed in nyc on gas lines. This is only interpretation inspector has. I also do not allow Teflon tape on any treaded joint on our jobs. All these fillers being applied to mask poorly made tread. Properly treaded pipe does not need any filler or glue. Just a matter of proper tools and know how. And I'm not that one old timer. We do condensing boilers all the time and are using Propress for a few years already. We are certified for Aquatherm and installed quite a few Cogen systems as well. But threaded joint must be done with pro dope. This is according to my understanding of a nature of treaded joint.
  • icesailor
    icesailor Member Posts: 7,265
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    Issues:

    With tape, that is never an issue. If it is a connection that calls for a 1/2" make-in, and you have it close to 1/2" as you get to the point, stop. It won't ever leak. If you go around again with a 2' wrench, you will stretch the fitting and it might leak.

    When you tighten Malleable gas fittings, without tape, it will be loose as you get to that point of stopping. You think you have to make another turn. 1/4 of the way around, it starts to tighten up, then it gets really tight and you have 90 degrees to go. Suddenly, it gets easier and never gets hard again. You might as well take the fitting out and throw it away because you just stretched and ruined it. Even worse with black cast iron fittings. Only, when they get easier to turn, they have cracked.
  • icesailor
    icesailor Member Posts: 7,265
    edited August 2014
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    Reason to comply:

    I'm sure that they have their bogus and prejudiced reasons.

    Like thicker tape on gas. The tape just fills the microscopic annular spaces in the threads. Like candle or lamp wicking. Which usually peeled out when I made up well pipe.

    Those that can (like you) should be left alone and for the "Those That Can't" should stop hassling those of us that can with stupid, petty rules that make them feel impotent.

    You've cut, threaded and screwed together more pipe than I would have ever seen in my life. But if I EVER had to connect to something existing, that I didn't personally install, there is no way I would ever connect it without tape. Because if or when it leaked, I would be taping it to fix it. I've recently watched some real experts apply tape down here. They stick their finger inside the spool and quickly wrap 3 or 5 wraps in the male end of a fitting. With probably a 1/8" of tape past the end of the fitting hanging off the end of the threads. That's where the strings come from.



    I also remember fitting CI pressure fittings on boilers and feeling that sick feeling when the fitting suddenly becomes easier to turn and doesn't change. And you have to take it out and throw it away. At your expense. Or the one that cracked and no one noticed it until the system was turned on. Then, it was one heck of a project to replace it. They are never where it is easy.
    Mad Dog_2
  • CFH
    CFH Member Posts: 86
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    The only difference between yellow and white Teflon tape is the color. Read the MSDS sheets. Density varies by manufacturer. Just because home depot sells different color tapes to homeowners does not mean they do different things. If you need more density add a few wraps. A leak proof joint is a leak proof joint. One version of NFPA 54 stated that no where in this code does it prohibit the use of Teflon tape. Does it squeeze off the pipe and block the opening and possibly enter the piping, yes.
    ChrisJ
  • Steamhead
    Steamhead Member Posts: 17,008
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    Baltimore City prohibits tape on gas piping too. BTW, this thread dates back to 2014................
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
    SlamDunkMad Dog_2
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
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    CFH said:

    Why are you digging up a 9 year old thread?

    There was an error rendering this rich post.

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,839
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    These questions never make any sense.

    Depending on your location the inspector is likely to have his own "rules" weather it is in the Code or not.

    Just because NYC doesn't allow something doesn't make it the "GOLD Standard"

    Just follow the CODE in your own area and know that code better than the inspector and you will be fine.

    Most of the rumors about this pipe dope or that pipe dope or what color Teflon is mostly nonsense.


    I have battled with inspectors and have won most of my battles

    Including using the so called "thread protector couplings that come with the pipe". You can use them on 2 1/2" and up because 2 1/2 and up they have a tapered thread unlike the 2" and under which really are just thread protectors.

    Keep a code book in the truck and read it and know it.

    You will be a lot better off that to ask everyone and get caught in the rumor mill.
    Mad Dog_2
  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,245
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    I have used "Pro Dope" brand on gas, and Permatex in the 80s.  I prefer Megaloc and Rectorseal. .I'm with Steamhead: I don't care if its legal or not, never using
    Teflon tape on gas.  It is actually rare to see on Long Island 🏝 and In NYC.  If you do, its always a GC, HO, Handyman.  Mad Dog
  • WMno57
    WMno57 Member Posts: 1,408
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    Including using the so called "thread protector couplings that come with the pipe". You can use them on 2 1/2" and up because 2 1/2 and up they have a tapered thread unlike the 2" and under which really are just thread protectors.

    Ed, could you elaborate on this? I'm not understanding.
    Thank you

  • pecmsg
    pecmsg Member Posts: 4,961
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    WMno57 said:
    Including using the so called "thread protector couplings that come with the pipe". You can use them on 2 1/2" and up because 2 1/2 and up they have a tapered thread unlike the 2" and under which really are just thread protectors.
    Ed, could you elaborate on this? I'm not understanding. Thank you
    The coupling on the end of 20’ lengths of pipe are to protect the threads. They do not have a taper so are not designed for use. 
    WMno57
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,167
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    I just want to add that this thread sounds dopey

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    WMno57pecmsgSolid_Fuel_ManPC7060
  • Steamhead
    Steamhead Member Posts: 17,008
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    I just want to add that this thread sounds dopey

    (groan)
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
    Mad Dog_2
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,839
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    @WMno57

    Just as I said. On pipe size 2" and under the coupling threads have no taper and they should not be used (although we have all seen them used).

    On pipe 2 1/2" and larger the couplings furnished with the pipe are tapered and are ok to use.

    This is for the steel couplings furnished with the pipe. They are called "merchant steel couplings" and you can look it up.
    Mad Dog_2WMno57
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,646
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    When I started reading and saw icesailor I wondered if he was back. Then saw 2014.....
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • MikeL_2
    MikeL_2 Member Posts: 506
    edited April 2023
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      I've been using Teflon tape on gas piping for decade's. Never had an issue with inspectors. 
      I've taken apart Teflon taped gas piping & only found fragments of tape when the tape was not wound on properly. We are very precise when connecting to gas valves & always follow manufacturers instructions.
      Lengths of black pipe were always 21' long here, and typically came with only 1 running coupling.
    Mad Dog_2Larry Weingarten
  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,245
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    I'm sure it could be ok..just can't take that leap...ingrained in me from The Plumbing Elders...Mad Dog 
  • dullknife1
    dullknife1 Member Posts: 58
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    One of the many reasons Teflon is not allow on natural gas pipe threads is because natural gas is very drying, there’s no lubricant no in natural gas. One of the big reasons the liquefied natural gas auto industry didn’t make it. Combustion was fine, but there was no lubrication for the rings and the pistons. I guess they got tired of blowing engines. but Teflon tape will dry out your gas piping system and you will have leaks everywhere.
  • ChrisJ
    ChrisJ Member Posts: 15,919
    edited April 2023
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    One of the many reasons Teflon is not allow on natural gas pipe threads is because natural gas is very drying, there’s no lubricant no in natural gas. One of the big reasons the liquefied natural gas auto industry didn’t make it. Combustion was fine, but there was no lubrication for the rings and the pistons. I guess they got tired of blowing engines. but Teflon tape will dry out your gas piping system and you will have leaks everywhere.

    I don't think so Tim.
    It's PTFE, not rope.


    The ONLY reason PTFE tape isn't allowed with gas piping in some locations is due to issues with it getting stuck in gas valves etc. You can be as sloppy as you want with dope and there's no problem but take apart a connection that was made with PTFE tape and you can get debris in the line if you're not very careful.

    https://en.wikipedia.org/wiki/Polytetrafluoroethylene
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
    ethicalpaulSolid_Fuel_ManPC7060
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,646
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    I don't think PTFE needs any "lubrication" to seal for decades. It is about as immine to stuff as anything. I've seen it used on refrigerant fittings.....and it survived. Not that I ever recommend it. 

    LNG doesn't work in the auto industry due to heavy tanks and very low energy density compared to other liquid fuels. Nothing to do with piston rings. Gasoline ain't no lubricant!
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
    Mad Dog_2ChrisJ
  • hot_rod
    hot_rod Member Posts: 22,476
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    If you hold the teflon tape back two threads there will be no pieces inside the pipe.

    The problem is when you tape off the end.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    ethicalpaulpecmsgMikeL_2