What oring material do most lights use?

I’ve been involved in paintball both as a hobby and profession at various times, there any black orings = buna-n and any translucent or colored were urethane. Have always used Dow 33 on everything (except for a few guns that REQUIRED 55 for swelling to maintain seal) with zero issues, but it seems with flashlights there’s a lot of people saying not to use lithium grease.

What’s the “final word”? Does Dow 33 lack the petroleum products that could affect some seals, and are all black orings buna-n?

I think most of them are carbon/nitrile based like buna-n, with oil resistance so hydrocarbon lubricants can be used with them. Silicone grease is also ok. I tested the greases some flashlight manufacturers used and they weren’t silicone-based, btw.

I suspect the white/translucent ones are silicone. The high-end green/orange ones might be fluoropolymer.

Interesting, not surprised you’ve found that manufacturers weren’t all using silicone grease, some threads on my lights were much slicker stock than what Ive seen of it.

Ive been considering swapping my lights over to urethane because comventional thinking in paintball was that they could stand up to abuse better than buna (cuts, nicks from debris and screwing/unscrewing) but Im not sure what the maufacturers reasons for going with buna on lights are, just availability and/or cost?

It’s weird because the grease they (eg Nitecore) sell is silicone-based.

Urethane sounds stiffer. Will there be issues with it conforming and sealing? I’m thinking paintball o-rings also need to be watertight.

Stiffness/hardness is indicated by “durometer” on orings, so in theory equal duromter buna and urethane should act the same there.

IDK about ever being watertight (other than where the tank reg screws into the gun) but they can hold back a great deal of air pressure (easily 150+ PSI in some guns/components) in a radial valve.

Most lights use silicone O-rings.

Usually, you don’t need to put silicone grease on an O-ring, but just on the threads to improve thread movement and waterproofing.

What I do to silicone O-rings to help them stay water-tight is put a tiny bit of silicone grease on them.

Since they tend to absorb it, they will very slightly grow in volume, which helps a lot in regards to sealing, to the point of making a pop sound out of my lights when I open them up, meaning they are watertight.

Too much though, and they can become impossible to close.

I think it’s simple, most manufacturers will use the cheapest O-rings they found.

Yes, most use cheap silicone o-rings. Better option is silicone orings with known hardeness.
Much better are nbr 70 or even 90 shore.
As best is viton o-rings

Most of my lights, including dive lights, seem to come with cheap silicone seals. I’m not too happy about that. For non dive lights, I mostly don’t care. The seals on one light swelled from using silicone seal and would not fit anymore.

Which brings up the next issue. A lot of them sure seem to use non-standard sizing, or at least sizes I don’t have. I have a LOT of neoprene and viton O-rings and I’d say the probability of finding an exact fit in neoprene is less than 25%. Very annoying.

Thank you, it was driving me NUTS trying to think what those were called, I know a bunch of people would swap the seals in their guns for those too, lower friction supposedly IIRC (a big deal on some components that had dynamic seals).

A bit irritating to think that some of the more “premium” brands (price-wise anyway) would go with whatever simply cheapest. From what I remember even buying bulk (like 1000+ of a particular size and durometer) it was pennies on the dollar more expensive for most different materials other than specialty ones like high-heat, etc. that you could find on McMaster-Carr.

I really doubt they would go for an unusual size like that if cutting costs is the goal. Maybe just metric, or already swelling from factory lube/compressed by the body of the light?