To lube or not to lube O-rings?

Please register or login

Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

Benefits of registering include

  • Ability to post and comment on topics and discussions.
  • A Free photo gallery to share your dive photos with the world.
  • You can make this box go away

Joining is quick and easy. Log in or Register now!

I work with (and design) a lot of camera housings and o-ring seals in general. I lube the o-rings on my cameras. You're right that grease, especially if you use too much, does indeed pick up lint/hair/sand. Camera housing seals need to be inspected and cleaned regularly. I take out the o-rings and rinse them off in the sink, running my fingers around the whole rings to wipe off any old grease and debris before relubing and reinstalling. I also leave the housings closed to keep junk off the orings.
 
Camera housing manufacturers disagree. Properly lubricating these O-rings includes a very light coating and the process of lubricating it includes inspecting and cleaning any debris that accumulates. Your point is well taken in that debris can contaminate in the sealing surfaces. This is independent of whether the the O-ring is lubricated or not. Lightly lubricating O-rings not only allows the O-ring to move to the pressure-seating position in the groove, it facilitates installing it in irregular grooves. It is much harder for non-lubricated O-rings that stretch during installation to evenly equalize the stretch in the groove.

All O-rings move in the groove unless the pressure is very low, like less than half an atmosphere. See the illustrations in O-rings for Divers.

I avoided the term static because it has a particular meaning in O-ring engineering. Static O-rings mean that the seating surfaces are intended not to move relative to each other in operation. It does NOT mean that the O-ring does not move in the groove.

I disagree with the Camera Housing Manufacturers. This unnecessary and upproductive "advice" has resulted in many owners flooding cameras. I can't tell you the number of times I have seen people lubing and stretching these like taffy.

If it gets gritty, just rinse it off and pat it dry. Wipe out the grove with a microfiber. Done.
 
I work with (and design) a lot of camera housings and o-ring seals in general. I lube the o-rings on my cameras. You're right that grease, especially if you use too much, does indeed pick up lint/hair/sand. Camera housing seals need to be inspected and cleaned regularly. I take out the o-rings and rinse them off in the sink, running my fingers around the whole rings to wipe off any old grease and debris before relubing and reinstalling. I also leave the housings closed to keep junk off the orings.

You have perfectly described the problem. Putting Lube on these orings means that when they get dirty they have be manipulated and run through your fingers to rub off the grit now stuck in the grease. For some unsuspecting owners this results in too much tension and force, stretching the ring to the point that it pops out of the grove.

Just omit the grease and you merely have to rinse it off and let dry. Lubricating the oring does nothing to improve the seal of the housing and adds failure points.
 
I disagree with the Camera Housing Manufacturers. This unnecessary and upproductive "advice" has resulted in many owners flooding cameras. I can't tell you the number of times I have seen people lubing and stretching these like taffy.

The fact that some people incorrectly manage their O-rings isn't a justification not to PROPERLY lubricate them. However, proper lubrication also does not compensate for the lack of cleanliness or sloppy installation. All three are required.
 
Lubricating the oring does nothing to improve the seal of the housing
Not true. The grease helps the o-ring avoid strain and displacement as the housing is closed, keeps the rubber conditioned to prevent cracking/perishing, and allows the o-ring to more easily stretch and "flow" into any small imperfection it needs to fill as it deforms under compression. I believe it also does literally make the o-ring form a better seal on a micro level (think wet vs dry sucion cup on glass) but that's getting above my pay grade. Maybe Akimbo can speak to that.

I completely agree about clueless people mistreating o-rings though. I actually try to avoid designing large o-rings into consumer-operated assemblies whenever possible. For example, a battery with a connector will survive idiot users better than a battery housing with a big lid that needs to be opened for charging.

Divers should learn to treat o-rings properly though.
 
Good design must incorporate human factors and adapt to field experience and known failure modes. The minimal benefit from lubrication on a big camera seal is far outweighed by likely hood of failures due to this practice.
 
The one O ring that is not recommended to lubricate is the GoPro housing O ring. It's kind of cross between an O ring and a gasket.

The O ring in a DIN reg to valve interface does take torsion as the wheel is tightened so it also is not pure static. I think a thin layer of grease prolongs this O ring.
 
I clean and grease the GoPro gaskets anyway. They may recommend "no lube" so that clueless consumers don't go smearing axle grease on them. Haven't had one leak yet and I take them to (and slightly beyond) their max rated depth.

GoPro uses a very interesting gasket design. Seems to work well.
 
A year ago in Mexico one of the tanks I have there that a friend of mine uses for fishing had a leaky valve to tank o-ring. Tank shop had a device for cleaning up the mating surface. Still leaked. New o-ring, still leaked. Tighten more, still leaked. I tried to get them to lube the o-ring but they would not listen to the stupid gringo. Finally I went and got my silicone grease, put a thin layer on the o-ring, hand tightened the valve and asked the fill station operator to put air in it. He did, and was amazed when it didn't leak.
 
I also leave the housings closed to keep junk off the orings.


Yeah I also leave my housings closed with the Oring in a ziplock bag inside

Same with my scooters
 
https://www.shearwater.com/products/teric/

Back
Top Bottom