On 21/09/2019 17:09, Andy Burns wrote:
Steve Walker wrote:

I can't remember the number unfortunately, but Loctite used to do a
white thread sealant for pipework - we used to use it at work where
PTFE tape was banned. You used to put it on the male thread, screw it
into position and allow to set. It set rock hard, although it was
(just) possible to unscrew it if necessary.

I've seen a liquid PTFE sealer in Wickes

https://wickes.co.uk/slic-tite/p/227184

Yes, I've seen a number of different products, I just don't know if they
are the same as the Loctitie one that I knew - it was in a traditional
loctite style, red bottle, with a nozzle (no brush needed) and it set
solid. I am not sure whether the various options today set solid or just
form a seal.

It may well be worth trying one in this sort of case.

SteveW