There are two common references to plumber's tape: one that should correctly be called Teflon tape, and one that is more correctly referred to as metal strapping. In both cases, the product is referred to as plumber's tape since it is most commonly used by plumbers.

The plumber's tape more properly called Teflon tape is used to seal pipe threads against leaks. It is a thin, white tape that fills in the gaps between the pipe threads in order to seal against any leaks. It also acts as a lubricant for the pipe threads when tightening the fittings together. This type of plumber's tape is not an adhesive tape and cannot be used to fasten things together.

There are some basic steps to using plumber's tape or Teflon tape. Start by wrapping the tape around the threads at the end of the pipe. Do not go beyond the end of the pipe, or small pieces of tape may break free and eventually clog the system. Put a couple of loops of tape around the end of the pipe, then proceed to wrap all of the threads, overlapping half the tape's width each time.

Always wrap in the same direction that you will tighten the fitting onto the pipe. If you wind in the opposite direction, the tape will unwind when you screw the fitting onto the pipe. Keep the plumber's tape tight as you wind it onto the pipe so it pulls into the threads. In case you change your mind and undo the fitting, do not reuse the tape. Rather, remove the plumber's tape and use a new piece.

The other type of plumber's tape is really a type of strapping. This is a flexible metal strip with a regular series of holes running the length of the “tape”. It is generally used to provide mechanical support for piping. However, non-plumbers have frequently found much more creative uses for this product.

Both types of plumber's tape can be purchased from any plumbing supply store. Be sure that you get the type you expect, and since the two are very different in function and look, confusion should be easily avoided.