Sylvain Van der Walde wrote:

Bosswhite jointing compound will. Don't use it too sparingly, though.


I'm not going to keep repeating myself, but I'll say it one last time.
There is no need for any PTFE, joining compound, hemp, spit, glue,
silicone or any other crap in a compression joint. Make the joint
properly and it won't leak.


--
Grunff