I tested out Loctite 222 on a Continental removable core inner tube recently. I removed the valve core with the Park Tool VC1 shown and put 2 small drops of Loctite 222 onto the threads and reinstalled the core then left if for a little while.
I then screwed a Lezyne threaded pump hose tightly onto it and when I unscrewed it the valve core remained solidly in place which was what I wanted, the Loctite also ensures that the core does not come out when using a screw fitting pump or CO2 cylinder which can be infuriating and costly.
Using the tool I was still able to remove the core if I needed to but it was a lot more difficult than without the Loctite, the shear force of around 6Nm could be overcome with hand tools but not fingers. This means that a valve extension for deeper rims used in this way could be reused.
So, all in all a success and a method I will continue to use. A lot more convenient than bits of plumbers tape and prevents those ghastly moments where you blow up the tyre only to find that you unscrew the valve core when disconnecting the pump 😩