How To Correctly Apply Teflon Tape to a Thread

When working with a pipe thread sealant tape (incorrectly referred to as Teflon tape), it is very important to correctly apply it to to prevent a leak.

This is one of those things that require few practice rounds to get comfortable. If you have some time, I highly recommend purchasing practice parts (they are relatively inexpensive) so that you are ready for your next plumbing projects.

Note
I wrote a post titled “When to use PTFE Teflon Yellow or White tapes or Pipe Dope” to talk about about different types of thread sealants and their applications.

Required parts and tools

• Threaded male pipe/connector – 1/2″ 90 degree brass elbow fitting

• Threaded female fitting – 1/2″ 90 degree brass elbow fitting male to female

• PTFE thread sealant tapes
  • LASCO White 1/2-inch Double Density PTFE Thread Seal Tape
  • Oatey Yellow 1/2-Inch Gas PTFE Thread Seal tape
  • I suggest buying both and practice to get a different feel

• To clean pipes and fittings after practice, you can try to use old toothbrushes, or something like this 3 piece brush set

Step-by-step Instructions

Over the years, I’ve learned that taking time and paying attention to little details will minimize the risk of leakage (very frustrating to take it all apart to fix a leak!).

In its simplest form, we are trying to apply the sealant tape from the end of the pipe and wrap the sealant tape under tension in the direction of the thread turns.

Each successive layer should overlap the previous layer by approximately 1/2 to 2/3 in width and continue wrapping until the entire threaded portion of the pipe is covered.

In most cases, 2 turns is sufficient (max of 3 turns). If you wrap it the wrong way, discard, and start with a new piece of tape.

1. For this exercise, let’s assume that our elbow piece is a RIGHT HANDED thread;
2. That means when you are looking directly at it, the threaded piece is designed to be tightened by turning right;
3. While looking directly at the elbow as if you are still installing it, visualize a thread sealant tape is wrapped in the OPPOSITE direction;
4. For example, a sealant tape is wrapped to the LEFT TURN for a a RIGHT HANDED thread;
5. It can get little confusing if you change your viewpoint so make sure that your elbow piece is DIRECTLY IN FRONT of you when visualizing. When installing a tape, this perspective will change because you need both of your hands to correctly install the tape;
6. Now take the your TEFLON / sealant tape roll, spool out approximately 3 inches of tape which will be just enough for 2 wrap turns on a 1/2″ thread (you do not want it too thick);
7. A circumference on a 1/2″ diameter is roughly 1.6″ (2 turns x 1/6 = ~ 3″). Obviously if your threaded pipe has a larger diameter, you will need a longer tape. If you need help with math, you can always use this calculator from About.com;
8. Hold down the beginning of the tape with your left thumb;
9. With your right hand, gently tug on the tape until you can see the outlines of threads;
10. You can let go of your left thumb once you complete the first turn
11. Continue to tug on the TEFLON roll and complete 2 additional turns and cut it off
12. Make sure that any part of the TEFLON tape does not go inside the pipe/joint (you don’t want a small piece to rip off later and clog something)
13. Carefully apply the threaded piece to the female coupling (if you back out the threaded piece for whatever reason, you need to install a new piece of tape)

Don’t do this!

If you wrap the thread sealant tape against the turning direction (wrapping it in the same direction), your thread sealant tape will end up bunching up which will prevent the threads from mating properly.

Wrapping Up

I know it looks very confusing at first but give it a try few times I promise you it will get easier. Just remember to wrap the sealant tape in the OPPOSITE DIRECTION of a thread.

Another option is to use a liquid sealant tape like Permatex Thread Sealant with PTFE which is good for preventing air and liquid leaks. Remember that you want to apply a nice, consistent thin layer, not goop up a whole bunch. It can get messy in a hurry so have a roll of paper towel nearby 🙂

Well, that’s it for this article. If you liked this article, would you please do me a favor and leave a comment and sign up for my newsletter? The signup form is on the upper right hand side of your screen. Thanks!

REFERENCE LINKS

• When to use PTFE Teflon Yellow or White tapes or Pipe Dope