Originally Posted by brewguyver
One of the big reasons for Teflon tape is to keep your threads from binding. Stick with Teflon tape, or nickel tape for connections outside your kettle. It has a higher temp resistance and is thicker.
If you don't use the tape and you get a leak and the threads bind, or if you ever want to switch things out, you'll have to replace the fitting (and potentially cut it out).
Don't go with pipe dope - Teflon tape is the way to go.
Im sorry, I don't mean to sound rude--even though I will--but that is absolutely not true at all. I'm a machinist, knowing threads is part of my job, not just a hobby; I don't say that to sound condescending but to imply that I literally have studied threads and what their shape is designed for. There are two types of pipe thread you will encounter in the general public DYI field: NPT, and NPTF. 95% of what you will buy and use is NPT. I could get into the specifics of the differences of each, but I'd rather it just be googled.
Tape is ~necessary~ for NPT threads if they are going to be subject to pressure without making a mechanical seal, or are going to be torqued to a seal, then loosened. It has nothing to do with lube, but actual seal. NPT threads aren't designed to seal mechanically, so thus they need tape to seal. They CAN be sealed mechanically, without tape, but then CANNOT be taken apart without compromising the seal.
Even if you deform the threads to a mechanical seal, and then loosen it, you can still use it with tape to make a seal. There is no way you should ever have to replace a fitting unless you a) applied WAY to much torque and deformed the threads, or b) crossthreaded the threads and destroyed them.
99% of threads are NOT one time use. If they get screwed up so that they can't be used again, chances are it's operator error, not because you didn't use "lube."