Best O-ring grease

Hi:

I have found Dow Corning "Molycoat" 55 (silicone) to be highly regarded among the paintball crowd. Underwater photographers and SCUBA divers, OTOH tend to use "Sea & Sea Silicone grease". Photo folks sometimes use greases recommended and supplied by their camera manufacturers too. Some are available from B&H Photo, Adorama, etc.

I was also considering Dow Corning High Vacuum grease 976V (also silicone).

Is it better to have a highly viscous grease? If so, 976V is about the best available. But I'm tempted to try the 55 since it's specifically designed for o-rings. However, the Molycoat 55 does have a property which concerns me. It "slightly swells" the o-rings for better sealing. But, being silicone, it does not break down the rubber. I'm not sure I want any swelling at all, since I generally want my lights to be easier turning, rather than tight. Though, with proper lube, they will probably be plenty easy to turn compared to their horrible dry condition now.

It seems clear that a silicone grease is best for o-rings, since neoprene or natural rubber rings will break down with hydrocarbon based greases. Only buna-N (nitrile), silicone, and PTFE o-rings are compatible with hydrocarbon greases. So if one doesn't know what their o-rings are made of, silicone offers the highest likelyhood of compatibility. Unless one has silicone o-rings, which is unlikely.

Does anyone here have experience using any of the greases mentioned?

Note I am *not* talking about grease appropriate for threads that must mate as well as conduct electricity. That's another subject... I know Nyogel is popular, but it is hydrocarbon based, so probably shouldn't be used on o-rings unless one knows for certain they have nitrile.

Thus, if one has both unknown o-rings *and* electrical threads in a flashlight, it seems two greases are needed!

Any other favorites?

Nyogel 759G and Nyogel 779ZC are recommended by many manufacturers, including SureFire. Synthetic bases. Another option is SuperLube, a synthetic teflon grease.

I used a synthetic grease with teflon in it to lube my lights. I won't ever use it again - for some reason the light started skipping modes and glitching. It also turned a nasty black, maybe from a little galling of the threads?

In any case, I bought a fat tube of Nyogel and i'm never using anything else.

For < $5.00, a tube of Radio Shack General Lube. The tube will last a lifetime, won't hurt the wallet and will do what it's supposed to do.

Suggestion: check MSDS (Materials Safety Data Sheet) for petroleum ingredients for o-rings that don't like oil based products. Also for other ingredients that might be corrosive, etc. Many MSDS forms can be found on-line at the manufacturers' web sites.

nyogel is hydrocarbon based? i didnt know that....yet everyone is reccomending it?

Crenshaw

this_is_nascar said:

For < $5.00, a tube of Radio Shack General Lube. The tube will last a lifetime, won't hurt the wallet and will do what it's supposed to do.

Click to expand...

I'm using a variation of TIN's plan. It works very well, lasts forever and isn't expensive.

Anyone into RC model cars?

They use a sillicone grease to lube differential assemblies.

I have been using this stuff, you can get it at any well stocked RC hobby shop. I have no clue what the grade is though, but I am pretty certain it does not contain petrolium.



So far it has worked just fine. I also use it to lube the gaskets on my dive watches, when I replace the batteries.

I'm sticking with my cheap dielectrical grease, it works, that's all I can say.

The line of topics can easily be searched and you'll find a lot of information on viscosity of different greases, on which thicken or stiffen up in use and make the flashlight threads harder to use, on which tend to collect more dirt and grit, on which have petroleum that could possibly affect o-rings, etc., etc.

It's really not that hard to find answers to a wide range of questions on CPF by using the search function and then making a post to get an answer if the information could not be found by a search. That way the thread might not be skipped over by the person who could answer your question in a heartbeat. Too many threads on one topic leads to getting that "flogging a dead horse" smiley and could well get the thread ignored because similar queries have been made five or six times in just a few days.

Getting a thread ignored, on a topic like this especially, might lead someone to use something that could end up damaging parts of their flashlight.

We should all learn to search first, and then post a query or even PM someone that you think might have the answer. Creative searching isn't hard. Hint: Avoid common terms like "flashlight" and stick to more specific terms like "viscosity" or "grit." See how that works and good luck!

chmsam is right. There have been hundreds of threads on this topic, and it has been flogged to death.

Please use the search function before starting threads.