Sorry Phil. Just relaying the info I was taught at the local union hall. Local 230 Plumbers, pipefitters, steamfitters and sprinklerfitters. Spent 8 years working as an industrial HVAC mechanic out of the hall. We were taught to always use tape as a lube and dope to seal all connections. Although there is a specific tape and dope for many applications. Then for different types of work (med gas, etc) there are even requirements on exactly how many wraps of tape and how much dope (by weight) on each type and size of fitting.
So to not make it difficult for the average user I made a general statement.