I have seen alot of recommendations on this topic, but general speaking most will say Nyogel 760G or Superlube.
I have used all the lubes mentioned in this thread and a few that are not and they all worked fine but I find I reach for the Nyogel more than any other for O-rings.
I use to use vasoline before all these exotic lubes came out. Worked fine but had a tendency to attract dirt. Now they say not to use vasoline because it deteriorates the rubber.
I have used vasoline on my rubber O-ring for my whole house water filter for 12 years, its still there and working fine.
I was being a complete smarta. I was just making fun of their mostly blue hued emitter choices. I’m sure their gel is just fine.
I like the screw on lid. Keeps everything inside instead of all over my little parts box. I use one of those really small brushes that women use for detailing their nails. Brushes on nicely. Don’t ask how I know more about nails than I care to admit.
Used vaseline before, then ordered some inexpensive silicon grease (unknown brand, AE or BG) which was too viscous for threads. Now I have a jar from Mountain Electronics which works great.
I bought a 3 ounce tube of Super Lube like 8 years ago, I barely made a dent in it, probably last me another 8 years, talk about getting your money’s worth
I use Super Lube Multi-Purpose Synthetic Grease (that I got from Harbor Freight). Super Lube makes different types of greases so you have to be careful which one you use for flashlights.
The “Multi-Purpose Synthetic Grease” is compatible with both nitrile and silicone rubber, which I believe is the material used for the O-rings in flashlights. The black O-rings are usually nitrile and the clear and color O-rings are silicone.
But the Super Lube “Silicone Lubricating Grease” is not compatible with silicone rubber. Even the Super Lube “Silicone O-ring” grease is not compatible with silicone rubber.
Well if you had some laying around then go ahead. I would still go with any form of silicone lube over dielectric grease.
I find that dielectric grease is sticky that’s why I use them especially on my keychain twisties. As for any different from silicone lube, I think it’s more economical to use silicone lube plus it moisturizes your o-rings
I use TEF-GEL on flashlights and our boat. It is a ptfe based substance that has no electrical conduction, never dries out, won’t wash away with moisture, and only needs one application. I think it was primarily developed for the marine industry. It’s expensive, but a two ounce tub will last quite awhile, and won’t go bad at room temperature, at least so far. My tub is eight years old and it’s about a third gone. It’s super sticky and will make a mess of things if not careful. I put some of it, along with some silicone on a piece of metal and left it in the sun for a few weeks. No discernible change to the gel. The silicone was gone however.
Years ago I was using silicone based grease for o-rings and such, but had to re-apply every year or so. After awhile I noticed black on my fingers from seals degrading, probably from not applying often enough. I was using silicone grease designed for seals and grommets. Silicone dries out and disappears eventually, as do most other seal treatments I’ve used. TEF-GEL was designed to prevent corrosion between dissimilar metals in contact with each other, but it works fine for seals. Anyway, no more black fingers and I only have to do the job once, as it never dries out. And, threaded parts disassemble with ease. Don’t get me wrong. If I put it back tight it stays that way, but won’t gall or lock up from corrosion. Best to clean surfaces first to remove the old lubricant.