Odd Leak

[klausi]

Good news: It was my TG6 which experiences a leak, and it's fine.

But, I would like to understand what was going on. I had in fact cleaned the o-ring and grove before the dive, re-lubed with original Olympus grease, and re-inserted. I do a lot of beach dives, so there is some fine sand on the o-rings occasionally, hence, the need to clean it.

The dive I did was to 18 meters, very nice muck diving off Negros Island/Philippines. I spend most of the dive at 14-18 meters. The leak happened after 25 minutes. I didn't go deeper, I didn't bump the camera into anything, no unusual event preceded it.

I would think that a poorly inserted/dirty/... o-ring would lead to a leak right away? How could there be such a delay to o-ring failure?

 

[Barmaglot]

Are you sure the leak happened through the main o-ring? It could be one of the buttons.

 

[klausi]

Are you sure the leak happened through the main o-ring? It could be one of the buttons.

That's a possibility, good point. Still, why after 20 minutes at ~ 18m, not right away?

 

[Barmaglot]

If it's a button problem, it could manifest when you press a specific button. It could also be dependent on depth - I'm quoting Oskra@RetraUWT from Wetpixel, regarding an incident where a pair of Retra strobes simultaneously flooded at 89 meters:

We have finished our pressure testing and found the very likely culprit for the flooding that was reported by the user.


1.) Firstly we conducted multiple 24-hour high-pressure tests at 12 bar and a 4 hour test at 15 bar. Testing was done with the user's strobes and a Supercharger from the same production batch as the flooded ones. We used a new Supercharger because the original ones had clear damage to the sealing surfaces which made them unreliable. In all the tests we've done with the user's strobes and undamaged Superchargers there was no indication of water intrusion or any other damage as a result of over-pressure. Please note that these test do not imply that our equipment can be safely used below the official rating of -100m.


2.) Because we could not reproduce the flooding incident at significantly higher pressures than reported by the user, and higher than the rating of our equipment, we started to introduce handicaps to the sealing. We used single o-rings instead of double o-rings and repeated all initial testing. We then installed wrong o-rings to the Supercharger. Despite using single o-rings and wrong o-rings we could not reproduce the flooding.


3.) We continued to apply handicaps to the sealing via o-ring maintenance. This is where we finally made a breakthrough. While testing with handicaps we found if there is too much silicone grease applied the seal can sometimes fail at around the equivalent of diving to -70m. Too much silicone grease in the grooves where the o-rings seat combined with high pressure can result in the silicone grease forming a pathway for water to come in. Perhaps the grease has accumulated through several greasing events until there was too much to sustain a seal during a high depth dive.


This is the only time we have been able to produce a flood during our testing with undamaged equipment. Since the depth is similar to what was reported and the fact that we have not been able to reproduce the flooding in any other case (even by removing o-rings, using wrong dimension of o-ring and testing for several months at much higher pressures than specified, etc.) we are convinced this was the reason for the flooding incident the user encountered.

 

[klausi]

Very good information, thank you!

If it's a button problem, it could manifest when you press a specific button. It could also be dependent on depth - I'm quoting Oskra@RetraUWT from Wetpixel, regarding an incident where a pair of Retra strobes simultaneously flooded at 89 meters:

 

[klausi]

Update: cleaned the o-ring again with lots of attention to any sand grain there might be, applied grease, the housing was ok during a 1 hour dive to 18 meters. I still don't quite understand how a leak can happen after 20 uneventful minutes, the "grease bridge" mentioned above sounds most likely?