In article , "Grunff"
says...
Rob Morley wrote:

Are you saying that it is not appropriate for compression joints?

Yes, among others.


But it can be a good quick bodge on a dodgy compression joint, at
least until you fix it properly.


I disagree. If a compression joint is leaking, and further tightening
doesn't fix the leak, it is unlikely PTFE will fix it.

Think about how a compression joint is made - the olive is squashed
against the pipe and against the two parts of the fitting. The only
reason for it to leak is if the pipe, olive or fitting is damaged, or it
hasn't been tightened sufficiently.

So you wrap tape over the thread and the olive - with luck that will
contain the leak within the fitting.