I’ve recently had good luck with Master Plumber Faucet and Valve grease - waterproof, heat resistant, designed to be used with o-rings, valves, washers, etc. $2.99 at True Value Hardware.
I’ve compared it to Syl Glide, white lithium grease, dielectric grease, and others, and it seems less sticky, and more slick. The store rep said it’s silicone based, but you’d have to verify that. I like it. Mag recommended Vaseline. You likely didn’t do any harm, but you’re probably correct to switch to better.
After re-installing the ring, I’ve always used Hoppes 9 gun oil instead of grease on the threads, after cleaning them with alcohol. Things seem to spin together better, especially on Maglites.
- Some O-rings are petroleum-based. These are generally black, somewhat firm to fingernail pressure, and not very stretchy.
Some O-rings are silicone-based. These can be various colored, a bit softer to the fingernail pressure, and a bit more stretchy.
Yeah, there are a whole lot more but for the most part with lights this is what you likely have to deal with.
I know, not very scientific determination, but we are working with cheap lights here where they fabricate performance statistics. Probably most of the time they don’t have a clue what O-ring is bring used and it may change depending on what bulk shipment they got from wherever. I doubt you are ever going to find out.
For threads….metal on metal > use whatever grease or lube you want. Use sparingly, and try not t goop everything up with it.
But, most of the metal threads end in at a O-ring. If you are using the wrong lube, you may end up compromising the O-ring over time.
Not a critical O-ring, not a big deal. You may not even actually need it….so who cares.
I, on the other hand, am a scuba diver. My lights and my cameras are $$$ and those O-ring need to be clean, properly lubed, and taken care of, or I pay the price. Literally.
On petroleum-based O-rings you can use silicone lube.
On silicone-based O-rings you may be able to get away with petroleum lube….but those come in so many different formulations it’s a headache to sort out. I just use a ‘universal lube’ (generally damn expensive; Christo-lube, Tribolube) or one that I KNOW is formulated for silicone, generally less expensive but not terrible (stuff that comes with my camera equipment).
A small amount goes a long way so even an expensive tube is not that big of a deal.
Screw it up or don’t know, some hardware stores have a decent stock of O-rings. Then you know you can use silicone grease.
If it comes out of a spray bottle I wouldn’t trust it.
WD-40 is not a lubricant. It’s a [water displacement] and a poor lube.
For older lights without anodized threads in the tailcap, i find that candle wax does the trick best.
Use the softest candle wax you can find, which will stick to the aluminium and smear rather than crumble.
Unlike any other lubricant, it doesn’t dissolve the aluminium, so you don’t get that awful grey gunk you normally get, even with lumpy silicone grease.
True story.
Thanks. You’re the person to ask this question I’ve had. At some point, do you guys have to just replace the Orings on a time schedule to maintain the waterproof ratings?
I have lights that I’ve kept the rings in good cond. for long periods of time, but I don’t really know if they’re as water resistant as they used to be. Lots of use can fatigue some materials, especially cheapo stuff.
i tried marine grease on one light and it seems ok so far; will see over time how the o-rings survives
advantage is that it is not water soluble. so will keep water out of the light
desadvantage is that if you get some on fingers, it is difficult to clean…
as for o-ring compatibility with grease types, it will depend on the elastomeric material used, for exemple :
- silicon might not like some greases. silicon is expensive and i would be surprised to find it there, not compatible with oil, but excellent on high and low temps- quick curing too
- acm should be fine - perfect for oil, not good with alcool
- nbr may be ok - cheap , excellent with water and alcool, not good with oil
epdm may not like cheapest material only good with water
others excellent materials like fkm, viton, hnbr would not be used because of cost
Well, I have been using Petroleum Jelly.
No problems so far with any o-rings, but based on what I have read in this thread I believe it’s a good time to invest in something more o-ring friendly