Any suggestions for the longest lasting o-ring material in a flashlight application? I’m not as worried about wearing the o rings out on my less frequently used lights but I would like to maintain their performance over time. Most of my critical duty lights see very little use and in all honesty probably won’t get updated until there is a SIGNIFICANT breakthrough in lighting at this point.
Would nitrile or silicone offer better longevity? I don’t mind changing what I use for a lubricant if necessary (right now I use silicone grease on some and nyogel on others).
With nitrile rings you can use silicone grease as a water repelling lube.
With silicone rings, every lube swells or eats the silicone over time. Especially silicone grease will swell silicone rings and turn them into a sticky goo over time. This could be intentional, if it will not be opened frequently, as it will need replacement as soon as a a slightest moment of friction is applied to the goo. This includes pressure (diving/high altitude/space), which will then break the viscous gooey seal very easily, especially at low temperatures. The goo can easily glue everything together, making unscrewing the flashlight almost impossible.
Not at all. With nitrile oring yo can use silicon grease or PAO grease.
With silicone o-ring yuo can use a wide list of greases, except silicone grease.
And we should understand, that a lot of greases that called silicone is not on silicone base oil, but thickened by pyrogen silicium, that’s not the same. Such greases are safe for silicone o-rings, and, if based on PAO base oil - for nitrile.
Viton comes in all kinds of sizes.
FWIW, unless it’s a dive light requiring excellent fit, the exactness is not crucial. It should feel a bit snug when it hits the O-ring, but not shove it out of the groove or be difficult to twist on.
I’ve had O-rings in dive applications last for years with no problem. Some of the stuff that comes on lights though is pretty cheap crap.
