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Teflon tape vs. Dope/thread
Awl--
I've been left in the lurch a few times by teflon tape on threaded joints, where I just couldn't get rid of air/water leaks--proly cuz of chinese fittings! I've seen plumbing fittings that go together like a nut on a bolt! OTOH, pro dope/thread, messy and crappy as it is, has always been super-reliable, and in fact fixes the teflon problems. Can you use pro-dope by itself, w/o thread? Ace, I think, makes a teflon dope--messier than the Hercules trad'l dope. What do people here use, and when? The bigger the pipe is, the more I lean toward prodope/thread. Smaller stuff, like 1/4", I'll much prefer teflon. Anything better than the Hercules pro dope? What are people paying for teflon? A buck for the 1/2" rolls seems a bit much. HD: $1--and up. A local good hardware store (Schalls in Yonkers): 75c!!! Thanks! ---------------------------- Mr. P.V.'d formerly Droll Troll |
"Proctologically Violated©®" wrote in message ... Awl-- I've been left in the lurch a few times by teflon tape on threaded joints, where I just couldn't get rid of air/water leaks--proly cuz of chinese fittings! I've seen plumbing fittings that go together like a nut on a bolt! OTOH, pro dope/thread, messy and crappy as it is, has always been super-reliable, and in fact fixes the teflon problems. Can you use pro-dope by itself, w/o thread? Ace, I think, makes a teflon dope--messier than the Hercules trad'l dope. What do people here use, and when? The bigger the pipe is, the more I lean toward prodope/thread. Smaller stuff, like 1/4", I'll much prefer teflon. Anything better than the Hercules pro dope? What are people paying for teflon? A buck for the 1/2" rolls seems a bit much. HD: $1--and up. A local good hardware store (Schalls in Yonkers): 75c!!! Thanks! There are different grades of teflon tape. Once I started using the thick pink stuff (which is hard to find) instead of the thin white stuff, I stopped having leaks. |
I don't use teflon tape much anymore. I use teflon-bearing pipe dope
instead. Stuff just plain works. - GWE Kris wrote: All-- I've been left in the lurch a few times by teflon tape on threaded joints, where I just couldn't get rid of air/water leaks--proly cuz of chinese fittings! I've seen plumbing fittings that go together like a nut on a bolt! OTOH, pro dope/thread, messy and crappy as it is, has always been super-reliable, and in fact fixes the teflon problems. Can you use pro-dope by itself, w/o thread? Ace, I think, makes a teflon dope--messier than the Hercules trad'l dope. What do people here use, and when? The bigger the pipe is, the more I lean toward prodope/thread. Smaller stuff, like 1/4", I'll much prefer teflon. Anything better than the Hercules pro dope? What are people paying for teflon? A buck for the 1/2" rolls seems a bit much. HD: $1--and up. A local good hardware store (Schalls in Yonkers): 75c!!! |
"Grant Erwin" wrote in message ... I don't use teflon tape much anymore. I use teflon-bearing pipe dope instead. Stuff just plain works. - GWE Oatey makes a teflon-filled dope in a squeeze tube that's not so messy as a can and swab. The stuff is the tits for hydraulic work, and any air work with flow-limiting valves that might get gummed up with a loose hair of teflon tape. LLoyd |
Dope is the old method while teflon is the new method.
I prefer to first testfit the joint to insure that it is going to seal first due to the inconsistency of some of the fittings nowdays (chinese crap!) and then use teflon on them. I do make sure that the joint is tightened to the point where it really doesn't need tape to do the job right but the tape makes getting to that point easier. The pipe joint is actually designed to not need any filler compound but that takes longer and uses more force than using a lubricant to help in the job. -- Why isn't there an Ozone Hole at the NORTH Pole? |
"Proctologically Violated©®" wrote in message
... | Awl-- | | I've been left in the lurch a few times by teflon tape on threaded joints, | where I just couldn't get rid of air/water leaks--proly cuz of chinese | fittings! | I've seen plumbing fittings that go together like a nut on a bolt! I've come to understand that the tape is not for sealing. It is to keep the threads from corroding together and allow for removal. Having recently taken a steel fitting out of an aluminum casting, still holding the aluminum threads, it makes perfect sense. I use hylomar or Indian Head shellac for sealing threads. No leaks yet. |
carl mciver wrote:
I've come to understand that the tape is not for sealing. It is to keep the threads from corroding together and allow for removal. Having recently taken a steel fitting out of an aluminum casting, still holding the aluminum threads, it makes perfect sense. OK, check this out. Take any pipe joint you want, wrap it in teflon tape, thread the joint together as tightly as it would be in real life, then take it apart and see ALL the teflon tape gone from the joint. Unless it's wiping magic invisible teflon oil onto there, it won't prevent squat for corrosion. Tapered pipe threads seal by crushing together. The teflon tape just helps it slide in there a little. Teflon pipe dope doesn't really stay in there either, but it is my opinion (and those of several pro plumbers and pipefitters I know very well) that it comes much closer than teflon tape. GWE |
In article , Lloyd E. Sponenburgh
says... Oatey makes a teflon-filled dope in a squeeze tube that's not so messy as a can and swab. The stuff is the tits for hydraulic work, and any air work with flow-limiting valves that might get gummed up with a loose hair of teflon tape. I've known this as "SWAK" which I think is a swagelock trade name. This having been said, I use teflon tape nearly exclusively, never had any leaks. The key to not getting any sealant in the flow is to keep the tape off of the first thread in the fitting. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
Do any of'em use thread?
---------------------------- Mr. P.V.'d formerly Droll Troll "Grant Erwin" wrote in message ... carl mciver wrote: I've come to understand that the tape is not for sealing. It is to keep the threads from corroding together and allow for removal. Having recently taken a steel fitting out of an aluminum casting, still holding the aluminum threads, it makes perfect sense. OK, check this out. Take any pipe joint you want, wrap it in teflon tape, thread the joint together as tightly as it would be in real life, then take it apart and see ALL the teflon tape gone from the joint. Unless it's wiping magic invisible teflon oil onto there, it won't prevent squat for corrosion. Tapered pipe threads seal by crushing together. The teflon tape just helps it slide in there a little. Teflon pipe dope doesn't really stay in there either, but it is my opinion (and those of several pro plumbers and pipefitters I know very well) that it comes much closer than teflon tape. GWE |
Oh yeah, excellent observation on the "disappearing teflon"!! I always
wondered what was up w/ dat!! Which explains why, when the threads of fittings don't quite "make-up", that teflon is not so useful, whilst string/dope is. Ahm thinkin anything over 1", 'n' ahm usin string/dope. ---------------------------- Mr. P.V.'d formerly Droll Troll "Grant Erwin" wrote in message ... carl mciver wrote: I've come to understand that the tape is not for sealing. It is to keep the threads from corroding together and allow for removal. Having recently taken a steel fitting out of an aluminum casting, still holding the aluminum threads, it makes perfect sense. OK, check this out. Take any pipe joint you want, wrap it in teflon tape, thread the joint together as tightly as it would be in real life, then take it apart and see ALL the teflon tape gone from the joint. Unless it's wiping magic invisible teflon oil onto there, it won't prevent squat for corrosion. Tapered pipe threads seal by crushing together. The teflon tape just helps it slide in there a little. Teflon pipe dope doesn't really stay in there either, but it is my opinion (and those of several pro plumbers and pipefitters I know very well) that it comes much closer than teflon tape. GWE |
I use teflon tape on everything but gas pipes, and I've never had a
leak. Are you putting on enough layers of teflon tape on the threads? For gas lines, I use conventional pipe dope, because the contained in the distributed natural gas seems to bond better with black iron gas pipe and pipe dope than with teflon tape. Also, this was the advice that I received from a friend who works for the local gas company. Harry C. |
In article , Grant Erwin says...
OK, check this out. Take any pipe joint you want, wrap it in teflon tape, thread the joint together as tightly as it would be in real life, then take it apart and see ALL the teflon tape gone from the joint. Unless it's wiping magic invisible teflon oil onto there, it won't prevent squat for corrosion. Tapered pipe threads seal by crushing together. The teflon tape just helps it slide in there a little. Teflon pipe dope doesn't really stay in there either, but it is my opinion (and those of several pro plumbers and pipefitters I know very well) that it comes much closer than teflon tape. The sealant (tape or dope) seals the helical gap that remains above the crest of the male threads. If one sufficiently overpressures an NPT fitting, the helix of teflon (or other sealant) will extrude out of the fitting. I've seen this happen. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
RectorSeal Works well for me. Compatble with almost everything, except
oxygen. --Doozer in Buffalo |
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On 29 Apr 2005 12:08:18 -0700, jim rozen
wrote: In article , Lloyd E. Sponenburgh says... Oatey makes a teflon-filled dope in a squeeze tube that's not so messy as a can and swab. The stuff is the tits for hydraulic work, and any air work with flow-limiting valves that might get gummed up with a loose hair of teflon tape. I've known this as "SWAK" which I think is a swagelock trade name. This having been said, I use teflon tape nearly exclusively, never had any leaks. The key to not getting any sealant in the flow is to keep the tape off of the first thread in the fitting. Jim Jim, The first time I did gas piping using black iron pipe I was told to use teflon tape. EVERY joint leaked, even though all were tightened correctly. And none could be made leak free with further tightening. After speaking to some who knew, I bought the teflon pipe dope. It always works with black iron gas piping. Never had a leak since. But on all the brass fittings it's teflon tape. Never had any clogs or pieces of tape get into the inside. Eric |
Grant Erwin wrote:
carl mciver wrote: I've come to understand that the tape is not for sealing. It is to keep the threads from corroding together and allow for removal. Having recently taken a steel fitting out of an aluminum casting, still holding the aluminum threads, it makes perfect sense. OK, check this out. Take any pipe joint you want, wrap it in teflon tape, thread the joint together as tightly as it would be in real life, then take it apart and see ALL the teflon tape gone from the joint. Unless it's wiping magic invisible teflon oil onto there, it won't prevent squat for corrosion. Tapered pipe threads seal by crushing together. No they don't, not NPT threads at least, if they are made to spec. Check the thread form drawings in Machinery's Handbook and you'll see that the crests of male NPT threads are truncated, which creates the well known "spiral leak path" requiring some kind of "pipe dope" to plug it. NFTF ("Dryseal") threads, available on some small sized brass fittings, have a form which provides the slight crushing action you refer to and are intended to provide a tight seal without dope. The "F" in NPTF stands for "fuel" as those threads were originally designed to be used on fuel fittings long before Teflon or other fuel resistant pipe dopes were a twinkle in some chemist's eye. The teflon tape just helps it slide in there a little. Teflon pipe dope doesn't really stay in there either, but it is my opinion (and those of several pro plumbers and pipefitters I know very well) that it comes much closer than teflon tape. GWE Jeff (Who remembers using cotton string to seal pipe threads in his earlier days.) -- Jeffry Wisnia (W1BSV + Brass Rat '57 EE) "As long as there are final exams, there will be prayer in public schools" |
On Fri, 29 Apr 2005 17:14:57 -0700, Eric R Snow
wrote: On 29 Apr 2005 12:08:18 -0700, jim rozen wrote: In article , Lloyd E. Sponenburgh says... Oatey makes a teflon-filled dope in a squeeze tube that's not so messy as a can and swab. The stuff is the tits for hydraulic work, and any air work with flow-limiting valves that might get gummed up with a loose hair of teflon tape. I've known this as "SWAK" which I think is a swagelock trade name. This having been said, I use teflon tape nearly exclusively, never had any leaks. The key to not getting any sealant in the flow is to keep the tape off of the first thread in the fitting. Jim Jim, The first time I did gas piping using black iron pipe I was told to use teflon tape. EVERY joint leaked, even though all were tightened correctly. And none could be made leak free with further tightening. After speaking to some who knew, I bought the teflon pipe dope. It always works with black iron gas piping. Never had a leak since. But on all the brass fittings it's teflon tape. Never had any clogs or pieces of tape get into the inside. Eric Same here, but I use dope on ALL fittings, brass or not, since the several times I pulled a chunk of tape out of the locked up or leaking air soleniode on a machine tool Gunner "At the core of liberalism is the spoiled child - miserable, as all spoiled children are, unsatisfied, demanding, ill-disciplined, despotic and useless. Liberalism is a philosphy of sniveling brats." -- P.J. O'Rourke |
In article , Jeff Wisnia says...
Check the thread form drawings in Machinery's Handbook and you'll see that the crests of male NPT threads are truncated, which creates the well known "spiral leak path" requiring some kind of "pipe dope" to plug it. Yep. And I saw a parker representative demonstrate that yes, the goop in the spiral leak path does indeed extrude out at extreme pressures - *before* a swagelock fitting will let loose. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
"Jeff Wisnia" wrote in message ... Grant Erwin wrote: carl mciver wrote: I've come to understand that the tape is not for sealing. It is to keep the threads from corroding together and allow for removal. Having recently taken a steel fitting out of an aluminum casting, still holding the aluminum threads, it makes perfect sense. OK, check this out. Take any pipe joint you want, wrap it in teflon tape, thread the joint together as tightly as it would be in real life, then take it apart and see ALL the teflon tape gone from the joint. Unless it's wiping magic invisible teflon oil onto there, it won't prevent squat for corrosion. Tapered pipe threads seal by crushing together. No they don't, not NPT threads at least, if they are made to spec. Check the thread form drawings in Machinery's Handbook and you'll see that the crests of male NPT threads are truncated, which creates the well known "spiral leak path" requiring some kind of "pipe dope" to plug it. NFTF ("Dryseal") threads, available on some small sized brass fittings, have a form which provides the slight crushing action you refer to and are intended to provide a tight seal without dope. The "F" in NPTF stands for "fuel" as those threads were originally designed to be used on fuel fittings long before Teflon or other fuel resistant pipe dopes were a twinkle in some chemist's eye. The teflon tape just helps it slide in there a little. Teflon pipe dope doesn't really stay in there either, but it is my opinion (and those of several pro plumbers and pipefitters I know very well) that it comes much closer than teflon tape. GWE Jeff (Who remembers using cotton string to seal pipe threads in his earlier days.) Still the way to go if the pipe holds water. Lampwick and dope if it's a fitting that would be hard to redo, e.g. in a boiler manifold. |
Lloyd E. Sponenburgh wrote:
"Grant Erwin" wrote in message ... I don't use teflon tape much anymore. I use teflon-bearing pipe dope instead. Stuff just plain works. - GWE Oatey makes a teflon-filled dope in a squeeze tube that's not so messy as a can and swab. I tried this stuff for oil at under 150PSI and all it did was leak. Teflon pipe thread worked fine. The stuff is the tits for hydraulic work, and any air work with flow-limiting valves that might get gummed up with a loose hair of teflon tape. LLoyd |
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