Aidan Karley wrote:
In article , Andrew Mawson
wrote:
But recently I've taken to Loctite 542 thread sealant which is
absolutely brilliant stuff - you can assemble threaded fittings finger
tight pointing where you want them, and within minutes you get a sound
seal and good mechanical fixing that can be undone later.

And it's tight to hydrogen!
(This is a very non-trivial point if you're plumbing laboratory
machines.)

Even 200 Bar H2!