Plumber’s tape is also known as thread seal tape, Teflon tape, and PTFE tape. You don’t need to use plumber’s tape on unthreaded joints, which you should use a liquid sealant for. Plumber’s tape is meant specifically for creating a tight seal between threaded plumbing joints.
For example, hold the pipe fitting horizontally in your left hand with the threads facing your right hand, then position the tape with the end facing down, so you will wrap the tape away from you. Wrapping the tape clockwise prevents it from unraveling when you screw the male pipe fitting into a female fitting.
You should be able to clearly see the threads after you wrap them. If all you see is tape or you can just barely see the threads, it is not wrapped tightly enough.
You can now screw the male fitting into its corresponding female piece and it will have a tight seal between the threads.
You can also use plumber’s tape to fix leaky connections between water lines and sinks. Shut off the water supply, place a container under the water lines to catch any water in them, and disconnect the lines. Remove any old plumber’s tape and wrap the threads tightly 2-3 times with new plumber’s tape. Reconnect everything and turn on the water supply, then test the faucet. Plumber’s tape can be used on waterlines provided it’s not a copper fitting.
You can also fix leaky shower heads and arms with plumber’s tape. Just make sure the water is off, then unscrew the shower head and arm and wrap the male threads 2-3 times with plumber’s tape, then screw everything back together and test the shower.
Plumber’s tape should never be used as a permanent fix for leaks. Just patch them up to contain the problem until you can replace the leaky pipes to provide a long-lasting fix.
