Let's Talk About Teflon Tape

[In The Doghouse]

I've used Teflon tape for years during my projects around the house. I used some this morning and realized that I really don't know how many layers around the threads are recommended, or what else I may not know. What I have done over the years has worked and has held the seal.

I know to go in the direction of the tightening threads and to keep it off the very end of the pipe. How many layers and how tight should it be wrapped? What's a good quality Teflon tape?

 

[ericg]

Good source here

Oatey 101: Thread Sealant Tape | Oatey

PTFE (polytetrafluoroethylene) tape, also known as plumbers tape, is wrapped on a pipe to help create a leakproof seal between the threaded joint of a male pipe and a female fitting. Thread sealant is used in many industries for various applications requiring a watertight and airtight seal. It...

www.oatey.com

 

[tominboise]

Three wraps and use pipe dope on the outside of it.

 

[kbuhagiar]

Good source here

Oatey 101: Thread Sealant Tape | Oatey

PTFE (polytetrafluoroethylene) tape, also known as plumbers tape, is wrapped on a pipe to help create a leakproof seal between the threaded joint of a male pipe and a female fitting. Thread sealant is used in many industries for various applications requiring a watertight and airtight seal. It...

www.oatey.com

Clear as mud, lol. Not as helpful as I would have expected.

Yellow is for gas, that part's easy, but what's the difference between Harvey and Oatey? Is one a higher quality?
"Choose the Harvey brand if you don't own the house and don't give a **** about leaks."

Then they sell six different types of general-purpose PTFE tape, but they are vague about selections criteria, so I still don't know which one is best for my particular application (whatever that my be).

And pink for water? What's wrong with the other 'general purpose' PTFEs?

I'm more confused than ever...

 

[aka Larry]

I'm no plumber, but pipe dope made a mess the couple of times I tried it. I've never had a problem with the Teflon tape when it's wrapped in the correct direction. I use 3-4 rounds myself.

 

[Rc_Guy]

Three wraps and use pipe dope on the outside of it.

Putting fire sprinklers in, we would dope the threads first and then tape them because the tape keeps dirt off the threads sticking to the dope if you don’t put the pipe up right away.

And I would usually do 2 1/2 to 3 wraps

 

[rlitman]

...Then they sell six different types of general-purpose PTFE tape, but they are vague about selections criteria, so I still don't know which one is best for my particular application (whatever that my be)...

Yellow is thicker and denser, and the color is made to make it easy to recognize that it's not the regular white tape. Most of the other color codes are brand proprietary marketing to let you know their product is better than everyone else's, but for the most part what differentiates better teflon tape from cheaper stuff is the density (cheap stuff may be foamy) and the thickness (thicker is better). The color itself isn't important, but you need to know when you're using thicker tape, so you don't end up winding on too much. To that end, the gray and pink tapes are so far as I can tell the same thing as the yellow.

There are special green tapes out there that are rated for oxygen use, because they're cleaned of any combustible oils. But that's a very specific edge case you don't need.

 

[dr_clyde]

The steamfitters and pipe guys I used to work with did 3 wraps of teflon and a slick of dope over the tape. Probably a bit belt and suspenders but it worked well and we didn't have leaks when done that way. Stainless we did tape and then used a small amount of food grade anti-seize over the tape. Helped prevent galling on the stainless threads if there was a burr or something.

We used Blue Monster for everything, tape and dope. We never needed the stuff for oxygen or natural gas service, but if you're doing those, use the correct grade.

I used to work at a large brewery, we had a lot of pipes...

 

[Wamsutta]

I try not to go more than two layers.

 

[BTL-A4]

For sprinklers I go 6 or so turns with the stuff you get (thin, white) at the big box stores.

 

[Hohn]

I'm no plumber but I've used more PTFE than I ever though I would.
I've frequently had pipe dope leak. Never had tape leak unless it was user error on my part.

These days I just buy the most expensive tape Menards has-- usually blue monster.

There's nothing wrong with using yellow "gas tape" for everything. It's just thicker and stronger because sealing gas is harder and more important than sealing water.

The number of wraps really depends on the grade of tape you use. With thick stuff, 2-3 can be quite sufficient. With thin stuff, even 5 might leak.

 

[Leon bee]

The tape and dope approach is one I learned entirely on my own years ago. By crawling way up under dirty old houses and into creepy crawl spaces. Also learned to always have a few of those gator bite type pipe caps on hand as well.

 

[tak1313]

I've used Blue Monster in the past as well, but I PERSONALLY have found the Oatey FasTape (gray) stuff to be better. I get it at the local HD.

Oatey® FastTape™ | Oatey

Oatey® FasTape™ is an all-purpose, professional-grade thread-sealing tape designed for use on a wide range of threaded pipes. Made for the pros by pros, this plumber's tape can be used on virtually any piping system including stainless steel, cast iron, PVC, CPVC, ABS, brass and chrome fittings...

www.oatey.com

It SEEMS to be SLIGHTLY thicker than Blue Monster, and a little "tougher."

 

[manwithtools]

Three wraps and use pipe dope on the outside of it.

The tape and dope approach is one I learned entirely on my own years ago.

I'm not sure when this trend started but it makes no sense to me. I'll bet you will not find any dope manufacture recommend tape too, or any tape manufacturer recommend dope along with their tape. My father was a steamfitter in a paper mill for 35 years and never used anything but tape. I've worked in the industrial automation world for 40 years and I'll I've had to use is tape. I have had to fix some pretty poorly made threads, but I've never had to add dope to get an air or liquid tight joint.

 

[Steve_P]

There is a white mil spec tape that I buy from either Zoro or McMaster and it's significantly thicker than the junk from HD. I've had a bunch of leaks from using only dope on 150 PSI air lines and stopped using it 20 years ago.

 

[dscheidt]

I'm not sure when this trend started but it makes no sense to me. I'll bet you will not find any dope manufacture recommend tape too, or any tape manufacturer recommend dope along with their tape. My father was a steamfitter in paper mill for 35 years and never used anything but tape. I've worked in the industrial automation world for 40 years and I'll I've had to use is tape. I have had to fix some pretty poorly made threads, but I've never had to add dope to get an air or liquid tight joint.

tape and dope used to be called for on large diameter pipe and fitting (> 2", typically.) Male side gets tape, female the dope. I use just tape (almost always blue monster, because it's reliably good and easy to get), because it works fine and dope is a messy pain. I'll use both on stuff big enough, or if I think the threads are not the best.

 

[ericg]

As mentioned by @rlitman , its all about the density. Yellow is thicker than regular teflon tape and meets spec from AGS and its color can be easily seen by an inspector. Thicker tape means less wraps. https://images.boshart.com/boshartimages/2024/02/PTFE_ThreadSealTape_TechnicalSheet.pdf

 

[Retired dozer fixer]

In my retirement I worked at a fertilizer dealer. Used miles of blue monster tape and Rector Seal dope. Liquid nitrogen fertilizer is hard to seal under pressure. Especially with stainless steel pipe and fittings which are all we used. 1/4” to 4”. Like was said earlier, 3-4 wraps of tape depending on size. Dope on female threads on 3” and larger

 

[Wamsutta]

For galvanized steel pipe, I gave up on Teflon tape. I use joint compound instead. I went to ACE and got the most expensive joint compound they had. Worked a treat like the UK guys say. In the exact same spot where Teflon tape was leaking, the joint compound made a good seal. What I do now is save the Teflon tape for plumbing fixtures like shower heads; works good on those applications.

 

[seber]

It's all pretty loose as long as you get enough tape to seal. One caveat though. We had Oxygen lines in the brazing department. I had to personally take the compliance officer with me to confiscate the pipe dope and teflon paste sealant from the operators. Do not use any paste of any kind with oxygen.

 

[M635_Guy]

This video was pretty helpful (if a little slow - I forwarded past the more obvious stuff).

Skip to 7:50. The net in terms of "how many wraps" is of 4-5 clockwise wraps. The manufacturer recommendation appears to be a minimum of 3. A tighter seal is achieved since the teflon is a lubricant.

 

[Rc_Guy]

The number of wraps really depends on the grade of tape you use. With thick stuff, 2-3 can be quite sufficient. With thin stuff, even 5 might leak.

The tape shouldn’t matter, the threads should, I worked with a few guys that never used tape, but always used dope.

I'm not sure when this trend started but it makes no sense to me. I'll bet you will not find any dope manufacture recommend tape too, or any tape manufacturer recommend dope along with their tape. My father was a steamfitter in paper mill for 35 years and never used anything but tape. I've worked in the industrial automation world for 40 years and I'll I've had to use is tape. I have had to fix some pretty poorly made threads, but I've never had to add dope to get an air or liquid tight joint.

Installing fire sprinklers, the threads had to be very good for testing the system and holding for many years or forever and everyone used dope, but some didn’t use tape.

So we all have our own opinions.

 

[no704]

I have some gray tape for high temperature. Think it has graphite in it. Have to cut it with a razor. Very expensive but works when the normal stuff doesn’t.

 

[Jim greengo]

Clear as mud, lol. Not as helpful as I would have expected.

Yellow is for gas, that part's easy, but what's the difference between Harvey and Oatey? Is one a higher quality?
"Choose the Harvey brand if you don't own the house and don't give a **** about leaks."

Then they sell six different types of general-purpose PTFE tape, but they are vague about selections criteria, so I still don't know which one is best for my particular application (whatever that my be).

And pink for water? What's wrong with the other 'general purpose' PTFEs?

I'm more confused than ever...

Pink is for steam,last I heard anyway.

 

[Jim greengo]

Rector seal Tplus 2 works for the majority of situations I've ever come across, and there's been a lot of them.

 

[Rinspeed]

I've used hundreds of rolls of Teflon tape in my life and can only say what has worked for me. For water or air I always, always use tape and dope. I like Monster tape and dope but also use Loctite 567 dope a lot as well. Both tape and dope add lubricity and that is exactly what you want for NPT fittings. Next the parts you are putting together have to be as tight, to a point, as you can get them. I usually do between 2-3 wraps but that's not really as important as getting them tight. Not all fittings are created equal, most of the **** you buy in the big box stores is from Taiwan. To compare low quality fittings to something like you get from Swagelok is a joke. Just because one technique you used didn't work out so well doesn't mean your technique *****, it's probably just that the fittings were out of spec.

 

[Beerhippie]

Here's what I've been using in the brewery since the last ice age:



My original boss--a professional pipe fitter and brewery builder--used that with the same brand dope. Note that this tape is approved for just about EVERYTHING.

I quit using the dope years ago and never missed it--certainly not the mess. 3-4 wraps, burnish it in with your fingers and Bob's yer uncle.

For many things nowadays, I use Loctite 542 thread sealer. The main exception is stainless, where the tape prevents galling.

Fun fact o' the day: The WL Gore company was experimenting with new stretching techniques for Teflon pipe tape when they serendipitously invented Gore-Tex. Last I looked, they still made pipe tape, too.

 

[Dagny]

I use anchor or ward . What is swagelok.

 

[Rinspeed]

I use anchor or ward . What is swagelok.

I should have clarified, Swagelok sells some of the highest quality fittings made. Mostly compression fittings but they do offer others. They are a little pricey but they almost never leak.

 

[Hohn]

I should have clarified, Swagelok sells some of the highest quality fittings made. Mostly compression fittings but they do offer others. They are a little pricey but they almost never leak.

Indeed. In our Cummins facilities, they are *everywhere*. My injector and fuel pump test stand rig is plumbed entirely with swagelok.

 

[ronkz650]

Tape has always leaked for me, 100% failure. Most equipment I bought where they used tape, such as air compressors. Motorcycle lift, pressure washers, you can all but bet on every fitting they used tape on will leak. I will never use it again. For me if I don't care if I need to ever disassemble I use JB weld on the threads. It will never ever leak, but not particularly easy to disassemble if ever needed, but with heat not too bad, otherwise Rectorseal #5. It never leaks for me. I'm no professional working with 2000psi or gas, but for home use on normal air and water pipe fittings, my experience.

 

[Dagny]

****** seal no 5 is my fav also.

 

[Beerhippie]

Tape has always leaked for me, 100% failure. Most equipment I bought where they used tape, such as air compressors. Motorcycle lift, pressure washers, you can all but bet on every fitting they used tape on will leak. I will never use it again. For me if I don't care if I need to ever disassemble I use JB weld on the threads. It will never ever leak, but not particularly easy to disassemble if ever needed, but with heat not too bad, otherwise Rectorseal #5. It never leaks for me. I'm no professional working with 2000psi or gas, but for home use on normal air and water pipe fittings, my experience.

Really? I've been using tape, etc, for many years and my joints don't leak. They just make funny noises when I stand up.

 

[Dagny]

I have a can of expando in the shop I have not used it yet suposed to work good on bad fittings

 

[tak1313]

I'm not sure when this trend started but it makes no sense to me. I'll bet you will not find any dope manufacture recommend tape too, or any tape manufacturer recommend dope along with their tape. My father was a steamfitter in paper mill for 35 years and never used anything but tape. I've worked in the industrial automation world for 40 years and I'll I've had to use is tape. I have had to fix some pretty poorly made threads, but I've never had to add dope to get an air or liquid tight joint.

I mostly use straight tape (ala the Oatey stuff I mention above), and occasionally have used dope (without tape), but being DIY, it's not like I do a lot where I would periodically come across problems, plus the biggest connection I've used is 1 inch.

My PERSONAL theory is the "tape and dope" thing probably started years ago when there was really only one option for tape - the cheesy standard white stuff that's super thin. As manufacturing got cheaper with more imports, the quality (and possibly thickness) started dropping. The cheaply made stuff started causing problems, especially where the 3 wrap rule was now insufficient, so people started using both together.

 

[M635_Guy]

Tape+dope seems like it would work, but not make either product better. It's enough overkill to do the job, but either product in the proper application should work just fine.

Tape has always leaked for me, 100% failure. Most equipment I bought where they used tape, such as air compressors. Motorcycle lift, pressure washers, you can all but bet on every fitting they used tape on will leak. I will never use it again. For me if I don't care if I need to ever disassemble I use JB weld on the threads. It will never ever leak, but not particularly easy to disassemble if ever needed, but with heat not too bad, otherwise Rectorseal #5. It never leaks for me. I'm no professional working with 2000psi or gas, but for home use on normal air and water pipe fittings, my experience.

100% failure probably means you're doing it wrong - not enough wraps, wrong direction, etc. Maybe you had a bad roll, but even the cheapo stuff is pretty reliable if used correctly.

 

[dscheidt]

I mostly use straight tape (ala the Oatey stuff I mention above), and occasionally have used dope (without tape), but being DIY, it's not like I do a lot where I would periodically come across problems, plus the biggest connection I've used is 1 inch.

My PERSONAL theory is the "tape and dope" thing probably started years ago when there was really only one option for tape - the cheesy standard white stuff that's super thin. As manufacturing got cheaper with more imports, the quality (and possibly thickness) started dropping. The cheaply made stuff started causing problems, especially where the 3 wrap rule was now insufficient, so people started using both together.

It's no doubt a carryover from the lampwick days. Before tape and modern dopes, plumbers used wick, basically cotton thread, wrapped around the male thread, and put in place with grease, linseed oil, or something like white lead in linseed oil. the grease mostly serves to keep the wick in place while it's assembled. Once it's assembled, the wick swells from moisture, and stops it from leaking. (There are thousands of miles of natural gas distribution pipe line that leaks from every joint, because modern gas is too dry to keep the wick wet....) Tape and dope is pretty much the same steps as wick and dope.

Remember what the point of wick, tape, or dope is: to fill the radial gap between the crest of one part and the root of the other. Pipe threads make contact on the sides, but there is a gap at the top and bottom, and the sealer used works by fillng that gap. It's also an assembly lube, making it easier to make the joint properly tight so the gap is as small as possible.

 

[cannuck]

Made up many thousands of fuel, oil, gasses and vacuum fittings over the years. Was also my job for 30odd years to teach others how to seal pipe, flanges, structures, etc. I had 4 levels of tapered pipe thread sealant: very small (1/16 and 1/8) small (1/4, 3/8 and 1/2) medium (1" - 2" NPT) and large (mostly 3" and 4". The very small stuff needs relatively thin tape (usually white stuff from fitting supplier). Small used "petro tape" (can't remember brand" and medium usually same stuff, but also sometimes gas fitter's tape of similar thickness from same source. All of these in 3 turns - but the magic is not only correct direction but how tight you pull it. Tape seals by being squeezed apart by thread with material filling the gap between tip of male thread and groove of female. Alway dry. That came from doing one large project with many unreachable fittings running hot napthenic base stocks (very powerful solvency). We tried it with the PTFE paste recommended by our fitting supplier. It worked great...until it got hot and flushed 100% of the paste out - requiring a megabuck disassemble/reassemble process taking it out of service at a critical time. Most of our joints were either hot napthenic oil or very deep vacuum - and in many cases both conditions in same fitting) and you know you got it right when you measure absolute pressures that don't even START to indicate until below 1/1000th of an atmosphere.

Large (3 & 4) fittings were all vacuum and sometimes done in 5 wraps of gas fitters tape but by far best a tar like goo (also no longer remember brand as fitting supplier knew what we needed and just handed it to whoever came to pick stuff up). If the black goo was not in the trailer I would allow people to do what my gas fitting friends do: 5 turns of gas tape with PTFE paste outside of male or inside of female (preferred but usually meant someone had to get off their lazy *** and climb 20' or so to goop up the female side), My belief is if you can't properly pull tape tight enough to self adhere inside of groove and CLEARLY see the thread form slopping the PTFE paste on the outside would buy you a bit of forgiveness by allowing the dry tape to slide over the wet paste without pushing the tape out of place.

From doing this for decades you would be surprised how many people CAN'T (or won't - but not my employees so never got to fire anyone over it, just reprimand and report) do this correctly.

 

[Stick-man]

I like the blue tape, the heavy stuff. Three to four wraps, depending on the quality of the threads. Really crappy chicom stuff might get more.

 

[rust in the eye]

A bit off topic; how many rolls of this stuff do you guys have kicking around? I had more then a dozen last time I rounded them all up. Seems I never have any T tape at hand when I need it so wind up buying yet another roll.
Application? A few turns, 3 or 4 perhaps. I've done with paste too but those connections were just messier so just tape these days unless threads look buggered and no replacement fitting.