Thread joints and Teflon tape question

This may seem like a not so good question, but, I am building a second bath and have mastered the solder challenge, also installation of pex and manifiolds. That said, I have a number of thread joints in the shower and bath, for example I am threading 3/4 flex pipe to my 3/4 tub fawcets. Many times when I have used threaded joints, I do not seem to get correct amount of teflon, nor correct tightning on the joint. On this tub, I have to get right as I will be closing it in and do not want any leaks. Is there a rule of thumb as to how many wraps around the male thread I should do with Teflon? Is there a rule of thumb as to how tight to tighten the joints? Any help would be appreciated.

Most use about three wraps with tape if it's a tapered thread.

If you have flex connectors with straight threads and seals, then you wouldn't use tape.

What do you mean by threaded flex connector? If it is a line like would be used on a sink faucet, they seal with a gasket, and tape will CAUSE a leak.

The fawcet is a porchet with 3/4 male thread. I could not find any 3/4 flex with female for tying to fawcet but am imporovising with 3/4 stainless flex with a female thread that was designed for hot water heater hook up. Will this work?

That would work, but not with Teflon Tape. They come with their own seals.

tape going in the right direction?

In addition to the comments above - to not use tape whre the threads are not supposed to provide the seal but a gasget or a flange is - is idea that when you do use teflon to make it go in the right direction. Perhaps you are aware of this - but boy am I sure slow on the uptake - you just wrap it around - duh - It took me ages as a diyer to have someone finally put me out of my ignorance with teflon and tell me that the tape wraps on in the same direction over a male pipe thread as if you were installing a female threaded piece over it (in the "on" direction). The simple things in life!!

Good points - we all sometimes miss the seemingly "obvious" things (I certainly have...)

On this installation, I'm assuming you will be testing the connection for leaks under water pressure before you close off the wall/ceiling?

One point here about those flexi connectors.....if you over tighten them you can distort the gasket or even worse cut the gasket on the end of the male threads.I like to use a small amount of thread sealant (I prefer "Pro-Dope") on the male threads ,then tighten hand tight plus a 1/4 turn.Pressurize your system and check for leaks...........done

poorplmbr said:

One point here about those flexi connectors.....if you over tighten them you can distort the gasket or even worse cut the gasket on the end of the male threads.I like to use a small amount of thread sealant (I prefer "Pro-Dope") on the male threads ,then tighten hand tight plus a 1/4 turn.Pressurize your system and check for leaks...........done

Click to expand...

ProDope RULES!
I used to use nothing but rectorseal till I bought some at a supplier that had only ProDope...has a better consistancy, spreads better and if it spills it doesn't cake all over everything nearly as bad as the yellow stuff.

question and a comment

I understand that tapered threads need sealant, and flares/gasketed/o-ring types do not. I have heard some people advocate using teflon tape on the nuts of unions, not to seal, but to ensure that they can be disassembled readily in the future. Any thoughts as to this being a good or bad plan?

Also, instead of the usual pipe dope or tape, I have had excellent success with a Loctite product, Loctite 567 Thread Sealant. Started using this at work on industrial hydraulic and pneumatic installations, and it works great. Might be a bit more expensive. It cures anaerobically (in the absence of oxygen) and seals well even if the threads are a bit dodgy. On of the knocks on using tape with more sensitive equipment is that little bits can dislodge and clog ports of valves and such (more applicable in pneumatics).


Greg