Teflon tape vs thread compound
- Thread starter Carbon12
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But pipe thread or tape isn't supposed to seal the connection, right? The seal in a tapered pipe joint is supposed to be via metal-to-metal interference between the tapered threads. The joint compound or tape is only there to lubricate the joint so that an interference connection can be made. Besides, no joint compound would make a gas or water tight seal anyway.
Also it can be beneficial to leave the first thread un-taped as noted but this is to prevent a stray piece of tape entering the piping system. Once you start tightening the joint the threads are going to cut through the tape regardless of how far down the thread you've wrapped the tape.
Also it can be beneficial to leave the first thread un-taped as noted but this is to prevent a stray piece of tape entering the piping system. Once you start tightening the joint the threads are going to cut through the tape regardless of how far down the thread you've wrapped the tape.
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I think the quality (thread finish etc) has gone down hill … last water heater I did (3 years back) was some of this. I used tape and the white sealant over that and still fought a few drips.
Maybe 40 years ago , I was working maintenance , at a grey iron foundry . We ran air lines in 2" black steel threaded pipe . We used Rectaseal of some sort .
I smeared it on thick . No problems .
I smeared it on thick . No problems .
I use Hercules Real Tuff white sealant and the thicker version of the Teflon tape the same time. First I clean the threads (both male and female) really well, then wrap the Teflon tape on male threads, and then apply the sealant on top of the Teflon tape.
Originally Posted by kschachn
But pipe thread or tape isn't supposed to seal the connection, right? The seal in a tapered pipe joint is supposed to be via metal-to-metal interference between the tapered threads. The joint compound or tape is only there to lubricate the joint so that an interference connection can be made. Besides, no joint compound would make a gas or water tight seal anyway.
Also it can be beneficial to leave the first thread un-taped as noted but this is to prevent a stray piece of tape entering the piping system. Once you start tightening the joint the threads are going to cut through the tape regardless of how far down the thread you've wrapped the tape.
Tape or sealant do have a function of lubricating the thread, but they also fill in the imperfections of the threads mating surfaces to make a seal.
But pipe thread or tape isn't supposed to seal the connection, right? The seal in a tapered pipe joint is supposed to be via metal-to-metal interference between the tapered threads. The joint compound or tape is only there to lubricate the joint so that an interference connection can be made. Besides, no joint compound would make a gas or water tight seal anyway.
Also it can be beneficial to leave the first thread un-taped as noted but this is to prevent a stray piece of tape entering the piping system. Once you start tightening the joint the threads are going to cut through the tape regardless of how far down the thread you've wrapped the tape.
Tape or sealant do have a function of lubricating the thread, but they also fill in the imperfections of the threads mating surfaces to make a seal.
Originally Posted by windeye
Tape or sealant do have a function of lubricating the thread, but they also fill in the imperfections of the threads mating surfaces to make a seal.
I could understand that to some extent in regards to tape, but how would a liquid sealant help with anything above a very low pressure? If there is a spiral path for leakage how could pipe dope seal against 80 PSI water?
Tape or sealant do have a function of lubricating the thread, but they also fill in the imperfections of the threads mating surfaces to make a seal.
I could understand that to some extent in regards to tape, but how would a liquid sealant help with anything above a very low pressure? If there is a spiral path for leakage how could pipe dope seal against 80 PSI water?
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Good paste contains solids. (blocking material) … 80 psi can squeeze out the liquid phase and solids block the micro imperfections … anything else is the mix is overall resistance of the materials in a tight space …
A number of master plumbers use paste over tape.
Just so happens calcium carbonate is also good at this … why some plumbing leaks "heal" themselves
A number of master plumbers use paste over tape.
Just so happens calcium carbonate is also good at this … why some plumbing leaks "heal" themselves
Last edited:
Anaerobic Pipe dope is my go to can be used with teflon tape. If you have damage threads fittings that bottom out and can be undisturbed for 12+ hours Xpando pipe compound its a powder that is mixed with water to a thick paste.
I have always used Teflon tape on PVC, ABS, and any other plastics.
LEAK LOCK on everything else.
http://www.highsidechem.com/leaklock.php
LEAK LOCK on everything else.
http://www.highsidechem.com/leaklock.php
Thanks for all the additional responses. The great thing about BITOG is we are a bunch of DIYers as well as professionals too.
Bought some Rectorseal T + 2 at Menards this evening. Hopefully it works for me. After additional research, it's apparently a mistake to try to install pvc female threads on metal male threads. Other way around is ok. I coupled the 1" pvc from the well to the brass tank tee using 1" pvc union which is only leaking on the side coupled to the brass. Tightening again yesterday just made it worse. Tomorrow I plan to replace the pvc union with a galvanized union. Going to use pipe dope instead of tape for the metal to metal connections and maybe just tape on pvc to metal.
This whole thing has been a pain. When I put in the new tank last week I thought I could remove the pipe between tank and tee and use the old tee. Nope. During the process I managed snap off the pvc and the copper water line attached to it. Might as well have been the hulk working on it. LOL. Should have known to start with everything new.
Bought some Rectorseal T + 2 at Menards this evening. Hopefully it works for me. After additional research, it's apparently a mistake to try to install pvc female threads on metal male threads. Other way around is ok. I coupled the 1" pvc from the well to the brass tank tee using 1" pvc union which is only leaking on the side coupled to the brass. Tightening again yesterday just made it worse. Tomorrow I plan to replace the pvc union with a galvanized union. Going to use pipe dope instead of tape for the metal to metal connections and maybe just tape on pvc to metal.
This whole thing has been a pain. When I put in the new tank last week I thought I could remove the pipe between tank and tee and use the old tee. Nope. During the process I managed snap off the pvc and the copper water line attached to it. Might as well have been the hulk working on it. LOL. Should have known to start with everything new.
Originally Posted by Carbon12
Domestic water pressure tank sprang a leak this week so I had to install a new one. Sealed all threaded connections with Teflon tape. In past experience as amateur DIY plumber the tape seemed to work better than thread compound from the little tube. However this time it has been terrible. I have tightened connections 2 times now and still have minor drips. Very aggravating.
What has worked better for you, tape or compound? If compound is better, what type and brand?
Thanks in advance.
When I was a small child, I remember my father working on our swimming pool plumbing (in ground). He used some very heavily scented primer and then other stuff. (I was 4-5 years old, sorry about being vague...). I never recall a single issue with it. It worked fine for decades.
Further, my house now was formerly owned and spec'ed by an engineer. He did some really awesome stuff in his time, and was a very particular individual, to the point that he kept 100% of every electric bill, as well as a written journal of the time he spent in what is now my house, hand-written (ex: "Arrived 10am, June 12, 2014, worked in garden 11-2pm, made fire in fireplace before bed").
Looking at the plumbing, all of the joints are secured with a blue chemical compound. I have never had an issue with anything in this house.
Domestic water pressure tank sprang a leak this week so I had to install a new one. Sealed all threaded connections with Teflon tape. In past experience as amateur DIY plumber the tape seemed to work better than thread compound from the little tube. However this time it has been terrible. I have tightened connections 2 times now and still have minor drips. Very aggravating.
What has worked better for you, tape or compound? If compound is better, what type and brand?
Thanks in advance.
When I was a small child, I remember my father working on our swimming pool plumbing (in ground). He used some very heavily scented primer and then other stuff. (I was 4-5 years old, sorry about being vague...). I never recall a single issue with it. It worked fine for decades.
Further, my house now was formerly owned and spec'ed by an engineer. He did some really awesome stuff in his time, and was a very particular individual, to the point that he kept 100% of every electric bill, as well as a written journal of the time he spent in what is now my house, hand-written (ex: "Arrived 10am, June 12, 2014, worked in garden 11-2pm, made fire in fireplace before bed").
Looking at the plumbing, all of the joints are secured with a blue chemical compound. I have never had an issue with anything in this house.
Originally Posted by Ws6
Originally Posted by Carbon12
Domestic water pressure tank sprang a leak this week so I had to install a new one. Sealed all threaded connections with Teflon tape. In past experience as amateur DIY plumber the tape seemed to work better than thread compound from the little tube. However this time it has been terrible. I have tightened connections 2 times now and still have minor drips. Very aggravating.
What has worked better for you, tape or compound? If compound is better, what type and brand?
Thanks in advance.
When I was a small child, I remember my father working on our swimming pool plumbing (in ground). He used some very heavily scented primer and then other stuff. (I was 4-5 years old, sorry about being vague...). I never recall a single issue with it. It worked fine for decades.
Further, my house now was formerly owned and spec'ed by an engineer. He did some really awesome stuff in his time, and was a very particular individual, to the point that he kept 100% of every electric bill, as well as a written journal of the time he spent in what is now my house, hand-written (ex: "Arrived 10am, June 12, 2014, worked in garden 11-2pm, made fire in fireplace before bed").
Looking at the plumbing, all of the joints are secured with a blue chemical compound. I have never had an issue with anything in this house.
I bet it's LEAK LOCK.
Originally Posted by Carbon12
Domestic water pressure tank sprang a leak this week so I had to install a new one. Sealed all threaded connections with Teflon tape. In past experience as amateur DIY plumber the tape seemed to work better than thread compound from the little tube. However this time it has been terrible. I have tightened connections 2 times now and still have minor drips. Very aggravating.
What has worked better for you, tape or compound? If compound is better, what type and brand?
Thanks in advance.
When I was a small child, I remember my father working on our swimming pool plumbing (in ground). He used some very heavily scented primer and then other stuff. (I was 4-5 years old, sorry about being vague...). I never recall a single issue with it. It worked fine for decades.
Further, my house now was formerly owned and spec'ed by an engineer. He did some really awesome stuff in his time, and was a very particular individual, to the point that he kept 100% of every electric bill, as well as a written journal of the time he spent in what is now my house, hand-written (ex: "Arrived 10am, June 12, 2014, worked in garden 11-2pm, made fire in fireplace before bed").
Looking at the plumbing, all of the joints are secured with a blue chemical compound. I have never had an issue with anything in this house.
I bet it's LEAK LOCK.
4WD
$50 site donor 2025
Thanks in advance. [/quote]
When I was a small child, I remember my father working on our swimming pool plumbing (in ground). He used some very heavily scented primer and then other stuff. (I was 4-5 years old, sorry about being vague...). I never recall a single issue with it. It worked fine for decades.
Further, my house now was formerly owned and spec'ed by an engineer. He did some really awesome stuff in his time, and was a very particular individual, to the point that he kept 100% of every electric bill, as well as a written journal of the time he spent in what is now my house, hand-written (ex: "Arrived 10am, June 12, 2014, worked in garden 11-2pm, made fire in fireplace before bed").
Looking at the plumbing, all of the joints are secured with a blue chemical compound. I have never had an issue with anything in this house.[/quote]
Reminds me of a couple things … 1). Our pool pump is sucking in some air … can't find it on surface, oh boy.
2). My camp was built by a long term tool & die machinist (stayed single his entire life) … between the tirelessness of this guy … and the amazing things he made … plus items he could bid on after a plant shut down … he made lots of "extras" affordable. Now some were a bit O/K, like 15k valves on the fish cleaning sink, but hey they never rusted in the wet salty air.
When I was a small child, I remember my father working on our swimming pool plumbing (in ground). He used some very heavily scented primer and then other stuff. (I was 4-5 years old, sorry about being vague...). I never recall a single issue with it. It worked fine for decades.
Further, my house now was formerly owned and spec'ed by an engineer. He did some really awesome stuff in his time, and was a very particular individual, to the point that he kept 100% of every electric bill, as well as a written journal of the time he spent in what is now my house, hand-written (ex: "Arrived 10am, June 12, 2014, worked in garden 11-2pm, made fire in fireplace before bed").
Looking at the plumbing, all of the joints are secured with a blue chemical compound. I have never had an issue with anything in this house.[/quote]
Reminds me of a couple things … 1). Our pool pump is sucking in some air … can't find it on surface, oh boy.
2). My camp was built by a long term tool & die machinist (stayed single his entire life) … between the tirelessness of this guy … and the amazing things he made … plus items he could bid on after a plant shut down … he made lots of "extras" affordable. Now some were a bit O/K, like 15k valves on the fish cleaning sink, but hey they never rusted in the wet salty air.
I hate Teflon tape. I recently discovered Hercules Real Tuff thread sealant. It's awesome stuff. I'll never go back to using tape. I just finished plumbing my air compressor piping and this stuff holds 175 psi of air pressure no problem. Every joint I did with tape leaked, no matter how ridiculously tight I made it. I redid the connections with the Real Tuff stuff and that fixed it. I also had a thread-on valve on my water plumbing that kept dripping. I redid it a few times with tape and it kept dripping. I finally redid it with Real Tuff and it doesn't leak a single drop anymore.
https://www.homedepot.com/p/Hercules-4-oz-Real-Tuff-Thread-Sealant-156152/203304169
https://www.homedepot.com/p/Hercules-4-oz-Real-Tuff-Thread-Sealant-156152/203304169
I really struggle with the concept of a liquid (regardless of the polymer solids content) holding back 175 PSI. The only thing that is holding back that kind of pressure is metal-to-metal interference in the tapered threads facilitated by the lubrication of the joint compound.
Originally Posted by kschachn
I really struggle with the concept of a liquid (regardless of the polymer solids content) holding back 175 PSI. The only thing that is holding back that kind of pressure is metal-to-metal interference in the tapered threads facilitated by the lubrication of the joint compound.
Try joining the fittings without the pipe dope and see how many leaks you will have. Report back with your findings then.
I really struggle with the concept of a liquid (regardless of the polymer solids content) holding back 175 PSI. The only thing that is holding back that kind of pressure is metal-to-metal interference in the tapered threads facilitated by the lubrication of the joint compound.
Try joining the fittings without the pipe dope and see how many leaks you will have. Report back with your findings then.
Originally Posted by BlueOvalFitter
Try joining the fittings without the pipe dope and see how many leaks you will have. Report back with your findings then.
One would assume the dope allows the threads to engage without premature galling or welding, before an adequate metal-to-metal seal is made.
Try holding back 175 PSI with an uncontained liquid and see how it works. Report back with your findings then.
Try joining the fittings without the pipe dope and see how many leaks you will have. Report back with your findings then.
One would assume the dope allows the threads to engage without premature galling or welding, before an adequate metal-to-metal seal is made.
Try holding back 175 PSI with an uncontained liquid and see how it works. Report back with your findings then.
4WD
$50 site donor 2025
Dehydrated mass is no longer a liquid
I have used cement pumped into a leaking thread and achieved 3000 psi squeeze pressure many times.
The solids collect and bridge against each other ... liquid phase phase is squeezed out ...
The pressure is the facilitator
Smaller threads we need to test to 5k might be precision made stainless ... there the tapered thread is of suitable quality to seal ... but even if phos coated ? In that case agree the lubricant is mainly to minimize galling. Only wish Home Depot pipe had fine enough threads to seal dry ... but many are just plain rough
I have used cement pumped into a leaking thread and achieved 3000 psi squeeze pressure many times.
The solids collect and bridge against each other ... liquid phase phase is squeezed out ...
The pressure is the facilitator
Smaller threads we need to test to 5k might be precision made stainless ... there the tapered thread is of suitable quality to seal ... but even if phos coated ? In that case agree the lubricant is mainly to minimize galling. Only wish Home Depot pipe had fine enough threads to seal dry ... but many are just plain rough
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