What Silicone Grease (or other lubricant)

Another vote for Superlube from me!
I was using some dielectric car grease before and didn’t notice any adverse effects, but Superlube is just much better value and works well.

Thank you for all your responses.
Superlube it is!.

The carlube silicone grease must be reacting with the O Rings.

https://www.fasttech.com/product/3586300-yezl-sg6-silicone-grease-for-flashlight

Feels waxy in the jar, lubes up nicely when you dab it on, the jar lasts nigh forever for <3bux unless you sell your own line of flashlights.

Here is a great resource on lubes for flashlights and info on their compatibility with different oring materials. I’ve been using Nyogel 760G for a while on all my lights and it was worth buying - takes a long time to dry out and is… “stickier” by which I mean it stays in place better.

Nyogel or Super Lube seems to be to best lubes for flashlights. But, be careful which Super Lube you pick since there are many to choose from and some may not be good for flashlights: Silicone grease for torches, which is the best?

I use Superlube as well but honestly, I’m getting tired of grease. It invariable attracts grit and gets on your hands when swapping cells. I’m actually thinking of trying some Johnson’s paste wax or some PTFE dry-lube spray. I have both in the workshop so perhaps a weekend experiment is in order.

The more important function of grease on the threads is to ensure liquids don’t penetrate past the oring or threads. Something that doesn’t fill any micro gaps or repel water misses the mark there, which may or may not be a concern for some or all of your lights.

I got this YEZL stuff, but got mixed results. On some lights it seemed to swell the o-ring a bit and/or felt a bit sticky, noticeably increasing the force required to twist the caps.

In the case of my C01S, after some time the head got stuck on the body and unscrewing actually just removed the bezel. It’s no fun trying to get a bezel-less head off with 100 lumens to the face. :stuck_out_tongue: P.S. the edges are sharp under there… enough to cut desperate fingers a few times. That light is just one frustration after another for me. Though that mule state was actually pleasant, circumstances notwithstanding.

Yet in other lights YEZL seems smooth enough without adverse effects.

Maybe the difference is whether the grease is in a liquefied or waxy state. In the jar it’s waxy, but I found body heat is enough to melt it and afterwards it stays mostly liquid-like with just the occasional bits solidifying. Maybe it needs to be melted really well when applied to function as intended.

Yeh, I’m pretty sure it’s supposta melt when being applied, to fill in all the nooks and crannies.

Just goggled the reviews, seems Jerommel reviewed it, too. Wonder whatever happened to him, hasn’t posted here (that I’ve seen) in ages.

Anyhoo, I always scrub the threads clean with O-rings removed and also cleaned. Rub the O-rings between greased fingers to completely cover them in a thin layer. Then apply a thin layer to the threads, stick the O-ring back, then another thin coating again to make sure the O-ring’s completely covered.

Less is more, no need to slather it on. Maybe that’s what’s “lumpy”?

Same with vaseline. When applying to something (never ever ever O-rings!!), it’s goopy, but rub it between your fingers and let body-heat warm it, or just start with it pre-warmed (eg, sitting in sunlight for a while), and it’s almost liquid and drippy.

Oh, just recalled a bit from the CPF thread posted above, to not use silicone grease on silicone O-rings.

Yah, here we go…

Don't use silicone lubes on silicone o-rings. The o-rings can swell and make your light almost impossible to get open.

Mebbe that’s why.

I use this: https://www.fasttech.com/p/1436202 for about 2 years.
Until now no problem.

Silicon is the go to for fountain pen repairers, largely used for O-ring lubing of Sheaffer Vacs and snorkels and I’ve been using it for 16 years without any observed o-ring swelling.

Silicon is also used for dive equipment and dive related o-rings, also been using for these applications without issue.

Would be interesting to see a confirmed account of o-ring swelling, IMO it sounds like nonsense.

Here are some silicone grease that I have. I use the high vacuum grease to stiffen the mode ring on a Sunwayman V11R. I mostly use the Superlube on flashlight O-rings because its in a tube and easy to direct where I want it. I will use the other silicone grease on other things as needed. For threads, I probably would just use one of the jars and dab with my finger.

Yeah, maybe some of the O-rings are different materials? Though I wouldn’t think so by their feel.

What I do notice is a dark gray-ish residue where the grease has been when I run my finger over it, suggesting it is breaking down the O-ring a bit? Do you get that too?

A cleaning and reapplication is due, so next time I’ll make sure it melts well and also try a different lube on some lights for comparison.

A lot of the time that residue is a small amount of the anodization on the threads wearing off and getting mixed with the lube. Usually when a like oring and lubricant/grease/etc. are used it will swell the oring or cause it to stretch out instead of causing it to dissolve.

Ah, worn off anodization dye could make sense.

I just find it strange that one or two O-rings felt swollen very soon after the lube application, while all the rest did not.

Haven’t really noticed, so can’t definitively say yes or no.

It will depend on the type of O-rings you are lubing. Some are silicone and some are nitrile (rubber). Silicone O-rings should be lubed with petroleum based lubricants and rubber O-rings should be lubed with silicone lubricants. If you use silicone lube on a silicone O-ring, it will react with it and cause it to swell. Vise versa with using a petroleum lube on a rubber O-ring.

It seems the black O-rings on my flashlights are nitrile, so SuperLube works fine. But the green (glow in the dark) and clear O-rings next to lens are silicone, so I don’t lube them. But they are a one time install vs the nitrile O-rings on the threads which get used with every battery change.

Worth noting that many other “rubbers” are compatible with synthetic [hydrocarbon] greases like Superlube synthetic (+ the silicone products) although natural rubber isn’t.

Here’s Superlube’s compatibility chart .

Good info on how to tell o-rings apart, Fan. Much appreciated. Now I’ll be sure to not run any silicone grease on the GITD o-rings of my torches.

Also for what it’s worth, I spread silicone grease on my threads and o-rings with an old toothbrush. Helps to prevent mixing in any fingerborne nastiness with the contents of the grease container.