IST Light - Too Hard to Turn On

[eponym]

Hi. I have a small IST light, innards modified by Packhorse (another SB member). It's a great light. My usual primary is a hand-mounted cannister light but the IST gives a good tight beam when I don't want to bring the can along.

Recently (over the last four months) the thing has become well-nigh impossible to turn on underwater.

It's a twist on/off design. I've cleaned the threads on the cap and body, and put silicone on the threads and on the o-rings lower down, but half the time in the water I have to give up trying to turn it on.

Can anyone suggest what the problem might be?

Thanks,
Bryan

 

[Kilili]

I have same problem with one...

 

[linger]

Does it turn on fine out of water? Does yours have 2 or 1 or 5 modes?
(I have the same light)

 

[Kilili]

Nope, and mine was built, on request, single-mode.

 

[eponym]

Just a single mode. Was also hard to turn when out of the water.

Have re-cleaned the threads (with a toothbrush) and the o-rings and have lubed all with silicone grease. Have started leaving it almost completely unscrewed between dives (after re-charging), only screwing it down closer to "on" before the dive.

That has helped keep it from locking up. I made three deep dives while conducting deep dive training yesterday and had no trouble turning it on before each dive.

-Bryan