Simple plumbing question re: teflon tape

[JDeereman]

Simple, stupid question regarding the use of regular white teflon tape - do the number of turns you are supposed to use vary with pipe size, thread type and pipe material? seems that the standard rules don't apply with very small or very large pipe sizes. also seems to work different for me with brass vs steel or iron fittings and fine vs coarse thread. what is your experience and recommendation? and please no advice about using teflon joint compound instead. i know it is better but today i need to know about using teflon tape. thanks.

Theo

 

[CCWKen]

I think a lot of folks get into trouble by using too much tape. NPT is supposed to be self sealing threads. Using too much won't allow the joint to go far enough up the taper to seal. I use no more than two wraps. It seems to fill enough of the "cracks" to make a good seal and allows easy disassembly later. If you do use it on hydraulic lines, make sure none of it comes within about 1/8" of the end of the fitting.

I'm not a plumber so take this as a suggestion only but I've run a lot of water, oil and air lines and never had a problem.

 

[Sherweld]

What he said.

Plumbing Repair Guide: How To Use Teflon Tape - ACME HOW TO.com

 

[ray66v]

3 turns of teflon is the rule I was taught by a master plumber. 1/2" wide tape covers up to 1 1/4" pipe use 3/4" wide tape on larger sizes.

Using a thin coat of dope with the tape is preferred by many plumbers. This helps to reduce the friction, and helps keep the teflon in tact.

 

[Bentwrench]

Above answers are correct. On brass & copper the threads are usually smoother so less friction two wraps is usually good. With brass, copper, and malable iron too much tape can lead to over tightning causeing the fittings to stretch resulting in leaks. Plastic and tape is a "no". Cast iron will not stretch but to much tape and really over tightning can crack them.

 

[ampsucker]

anybody else prefer pipe dope over the tape?

i bought a decent size bottle of the white pipe dope/putty and have never looked back. on the can it says it is good for water, air, natural gas, propane, hot/cold, just about anything except strong oxidizers.

whenever i've watched a plumber, they almost always seem to use the dope and not too many choose the tape option.

just curious if this is the norm or if there is some good reason to go with one over the other.

amp

 

[Inspector507]

Around these parts, tape is used for water, dope is used for gas.

 

[EddieWalker]

I put some new water valves under a kitchen sink on a remodel that I did that leaked with teflon dope. I took them off and used tape without any leaks. For the life of me, I can't figure out what I did wrong, but now I only use tape on water lines.

I use two wraps as I'm worried about too much.

Eddie

 

[JDeereman]

Thanks to all who replied. from your collective suggestions, i think i see where i may have been going wrong and not getting really great results. i'll go back and try again armed with this info. thanks!

Theo

 

[Wayne County Hose]

For as many posts as there are on this subject, you will get that many different answers. And, the other guys will always be correct.

 

[SPYDERLK]

I disagree, in part, with all answers given.
larry

 

[Iplayfarmer]

Thanks to all who replied. from your collective suggestions, i think i see where i may have been going wrong and not getting really great results. i'll go back and try again armed with this info. thanks!

Theo

Don't hog all the experience to yourself . Tell us where you went wrong and what you did different. Did your results improve?

We all want to learn from your experience so we don't have to make all the mistakes ourselves.

 

[JDeereman]

Don't hog all the experience to yourself . Tell us where you went wrong and what you did different. Did your results improve?

We all want to learn from your experience so we don't have to make all the mistakes ourselves.

For one thing, it never occurred to me that there was a wider teflon tape available for larger diameter pipes. i've been using 1/2 inch where i apparently should have been using 3/4". i will have to look for it. i've also been using 2 wraps max where i probably should have been using 3 wraps. but tightening is also a mystery to me. seems that where fittings finally line up, they are always either too loose and leak or it would take overtightening to get one more full turn. this usually means i need to start all over again and use more or less tape but often with no better results.

Theo

 

[Wayne County Hose]

I disagree, in part, with all answers given.
larry

Larry, we finally agree on something.

 

[SPYDERLK]

For one thing, it never occurred to me that there was a wider teflon tape available for larger diameter pipes. i've been using 1/2 inch where i apparently should have been using 3/4". i will have to look for it. i've also been using 2 wraps max where i probably should have been using 3 wraps. but tightening is also a mystery to me. seems that where fittings finally line up, they are always either too loose and leak or it would take overtightening to get one more full turn. this usually means i need to start all over again and use more or less tape but often with no better results.
Theo

If a fitting is a little too loose at lineup, take it apart and clean off the teflon scraps. Then put moly anti seize grease on the male, assemble, and tighten 1 turn beyond the too loose line up point. Remove, clean, rewrap teflon, and assemble to the line up tight point.
larry

 

[skipro3]

I realize you are probably speaking of conventional home water line plumbing, but thought it might be worth clarifying;

Tractor hydraulic plumbing should not use teflon tape on the threads. Instead use the paste with teflon in the mix and be sure it is rated for hydraulic oils and pressures.


Also; when using teflon tape on water pipes, the direction the tape is wrapped onto the threads matters!!

One more thing; gas pipes use a yellow teflon tape and water pipes use white teflon tape.

 

[TedLaRue]

... Then put moly anti seize grease on the male, assemble, and ...

Just a precaution, if you're working with fittings on an oxygen tank or lines (e.g., for an oxy/acetylene torch), don't use any oil or grease.

 

[TedLaRue]

The teflon tape varies in thickness. The yellow "gas" tape is supposed to be double density or twice as thick as the white stuff. But I use Oatey brand, and their white tape seems to be thicker than the cheap white tape and about the same thickness as their yellow gas tape. The thicker tape is much easier to work with (it doesn't twist as much and it doesn't stick to everything as readily).

The number of wraps depends on the tape which varies in thickness. I prefer the thicker tape, so I usually give it two wraps.

The tape should be wrapped around the male threads in the same direction as you turn the female part (so it doesn't tend to unwrap when you thread the female part on).

There's a controversy relating to using tape for gas fittings. Some argue that bits of the tape can plug the orifice of a gas fixture, which might be the reason some only use dope on gas lines.

 

[RedDirt]

anybody else prefer pipe dope over the tape?

i bought a decent size bottle of the white pipe dope/putty and have never looked back. on the can it says it is good for water, air, natural gas, propane, hot/cold, just about anything except strong oxidizers.

whenever i've watched a plumber, they almost always seem to use the dope and not too many choose the tape option.

just curious if this is the norm or if there is some good reason to go with one over the other.

amp

I've had mixed results with tape and mostly poor results with tape when used on water lines. I have followed the gist of most suggestions here so far and experimented with more and less tape wraps. I now use tape primarily for air lines and sometimes brass fittings. For most of the remainder of my pipe fit-up I use "Rector Seal" brand pipe dope. I've never had a leak with the Rector Seal.

 

[Iplayfarmer]

I think the reason the pros use the dope is because it's just easier and quicker.