Junkman
Super Member
Using Teflon tape can get you into a jam in a hurry when it is used on pipe threads. With Teflon tape, you loose to ability to know exactly how tight it is because there is very little friction. If you over tighten a device with a pipe thread, you can crack the block. Pipe threads, unlike a bolt are tapered. This taper is designed to create the friction that is necessary for a good seal. With a new item with pipe threads, the threads are very sharp and will also cut the tape as it is being screwed in. I have seen cast iron boilers that were ruined because an inexperienced person overtightened the pipe with Teflon tape on the threads and the cast iron was split open like a piece of wood as a result... Pipe dope is the better way.... and will do just as good a job of sealing the threads. This is one time more (pipe dope) is better, and more (Teflon tape) is worse. If you use Teflon tape for its original intended purpose, it is great. It was originally designed for use on old pipe threads that have been worn from assembly and disassembly. In the real old days, plumbers would use cotton thread and pipe dope to take up the gap that they now use Teflon tape for....