We all know that if you unscrew your flashlight enough and don’t tighten it, it will flood. But…did you know that you can also flood it by over tightening it? It is common for divers to damage their lights by tightening them down too much in hopes that they may stop it from leaking. As I gear up for dive season here and start taking more underwater pictures and videos, I am using my light more. I can tell you I ruined a flashlight this way I think. Hardly used the thing but was fanatical about tightening it. I didn’t want it to leak and corrode the inside. After some careful research, I have found out…I am dumbass.
When the lens cap is tightened down too far, the threads force the cap to bend in an oblong/oval shape. This allows for additional leaky areas. Depending on the size of the o-ring, it can also cause the o-ring to fold out of its groove due to this warping of the lens cover. Therefore, over tightening the lens cap on a light is often times a cause of leaks. Once the lens cap has past the o-ring, it should be sealed. Just turn the lens cap until it’s flush up against the body is all that is required, nothing more.