You could put a PCB in the tail cap that is isolated from the cap.
Contact would go through board to negative spring.
Most zebralights are like this, lots of other brands too.
It’s nothing more than a spring soldered to a copper coated pc board.
It will depend on the design of your light but may fix your issue.
Pretty much all Convoys I own have this problem, not only will this disable the lockout, the light also jumps through modes or flickrs wildly when removing/screwing on the tail cap.
No, you need to either reanodize it or apply some sort of powdercoat or ceramic coat, which is almost just as difficult and will add thickness possibly making the threads not fit together anymore.
Teflon tape for pipe threads is a good idea, worth trying, even if it does not last long. Use some lube on top of the tape may help it to stay in place. Sometimes you have to play the cards your dealt.
If you want to keep it really cheap you could take the PCB out of some broken electronics, find a section that’s mostly unpopulated, cut an appropriately sized disc, solder the spring to it, dab of glue, and stick it in the tailcap.
As long as there are no throughs on the section it will be isolated from the tailcap and give you trouble-free lockout.
Barely chamfer the copper side to isolate it from any exposed aluminum.
When I saw the title of the thread I got high hopes it was going to be something easy, but I don’t have any of the equipment necessary for reanodization T.T