btwn dives, do you leave your camera latched up in its housing?

[James R]

I wouldn't open my housing on a dive boat or out on the road in a truck (eg Bonaire). If the boat (or our truck) comes back to the dive center (camera room or my room) and I have a good reason to (batteries, SD card), then sure.

I have a vacuum system on my housing, and I like to give it at least 30min after I pump it down to ensure it holds.

 

[ballastbelly]

The entire premise of this argument is basically "if you have no reason to open it, should you?" which is an utterly stupid question. Underwater cameras are only opened for a reason. That reason could be any of a number of things, including changing media, charging batteries, decompression for air travel, preventing permanent deformation of the o-ring, etc., but there will always be a reason why you open it.

yes but does the o ring *really* deform when left alone at atmospheric pressure, for a day, a week? this is why i am asking. in the past i had the habit of opening my camera to allow the seal to relax after each dive day.

from what i am reading o ring damage primarily occurs during ascent/decent when huge pressure changes cause the housing edge to knife into the seal, hopefully the applied lubricant will keep the seal slippery and the housing wont be able to grab into it, the seal will be able to maneuver into its new 'at depth' shape.

i cant imagine any additional damage which will be suffered by the seal by leaving it at atmospheric pressure for a few days after surfacing.

 

[flareside]

yes but does the o ring *really* deform when left alone at atmospheric pressure, for a day, a week?

from what i am reading o ring damage primarily occurs during ascent/decent when huge pressure changes cause the housing edge to knife into the seal, hopefully the applied lubricant will keep the seal slippery and the housing wont be able to grab into it, the seal will be able to maneuver into its new 'at depth' shape.

Remember, the o-ring is not under atmospheric pressure, it is under the clamping pressure of the housing and it is that clamping pressure that is deforming the o-ring. And how long that clamping pressure is going to take to deform it is truly a function of the molecular makeup, quality, and age of the o-ring. I honestly doubt that leaving it for a few days or a week is going to hurt it. But where is the line between the person who leaves it for a week at a time 4 or 5 times a year and the person who leaves it for a week at a time 52 times a year. Opening it up every Saturday night for a few hours of air isn't going to save it.

I had never heard of the issue of the housing knifing into the o-ring. That should only be an issue with low quality housings. The real issue is deformation strain tearing at the molecular bonds and good housing design limits the amount of deformation strain. Age can be the real issue here, as the molecular bonds weaken with age.

 

[Golo]

The o-ring just by itself will not deform at atmospheric pressure, but when it is installed in the housing and the housing is closed, it is squeezed, and that can deform the ring. It's a matter of time.

That's why it is not recommended to store your housing closed with the o-ring installed.

In fact, there is even a specified test regarding this (compression set, A or B). Different rubber materials have different compression sets.

And I hope there is no housing out there that has an edge pressing against the seal.

Theoretically, if you apply more pressure (going deeper), the o-ring will squeeze against the sealing surface with a force according to the added pressure. If thre pressure is high enough and the housing can widthstand the pressure, then yes, an o-ring can start extruding into the gap between the two sealing surfaces and that can start damaging the material. At which pressure it is going to be a problem depends on the size of the gap and hardness of the rubber material. The silicone grease won't help at that point though. As far as I know the silicone grease is just a means to protect the rubber material from the saltwater (another reason could be to make it easier to close the housing).

Personally, on one occasion I have opened my housing on the dive boat, geared up and ready to jump in, to fix a memory card issue. I would not advise to do that, though And I probably would not have done that with an expensive camera, but with my 200$ compact it was worth it to me. I also have to change the battery after two, latest three dives, and I have done so many times, also on dive boats. In about 170 dives with a camera I never had a flooded housing, but that is no proof that it won't ever happen. It could happen on my next dive.

If I wouldn't have a reason to open it, I wouldn't though. Not after a day of diving, maybe after a week, maybe after a month...not sure, but at some point I would open the housing and check the o-ring for stuff like indentations. Latest I would open it after the dive trip.

 

[ballastbelly]

silicone grease is there to reduce friction of the housing in relation to the seal. As you go deeper, the crushing pressure will put both sides of the housing and the seal in (inperceptible) motion, if their surfaces get caught, by too much friction, they will tear at the weakest of the three, the seal.

 

[victor]

Open at the hotel to unload the pictures and recharge the battery.
If I could charge and download the pictures without opening I would do so.
Still I have the problem of changing the lens & port. Maybe 2 cameras? Have to ask her who must be obeyed if I can carry MORE stuff on holiday, oh yes and cost.

 

[Golo]

silicone grease is there to reduce friction of the housing in relation to the seal. As you go deeper, the crushing pressure will put both sides of the housing and the seal in (inperceptible) motion, if their surfaces get caught, by too much friction, they will tear at the weakest of the three, the seal.

The "inperceptiple" motion is no problem or danger to the seal. In terms of O-Ring design, this is a static seal. Also, the pressure change gradient is rather gentle. There are dynamic applications for O-Rings that are much, much more demanding in terms of tear and wear. And the maximum pressures we are dealing with in diving should be no problem, things like extrusion (which I mentioned in an earlier post) should also not happen at those relatively low pressures.

I also thought at first that the silicone grease could be there to protect the rubber material from the saltwater, however at the temperatures we are dealing with in diving, exposure to water is also nothing to worry about. It won't harm the rubber.

The main reason why one would lubricate/coat an o-ring in a static application with radial sealing is that you don't want it to be damaged during installation (in this case, closing the housing), or to just make installation easier. This is actually a bigger threat than one might think, and for that reason it is recommended to design the system with a lead-in chamfer.

As a matter of fact, the silicone grease itself has the drawback of making dust particles and hairs stick to the surface, which could in the end be the cause for a leak.

 

[drbill]

I "have" to open my housing after each day of filming since I edit my footage after I'm through. I re-seal the housing without the camera in it, recharge the camera and LCD batteries and am ready to dive again the next day. I am not as anal as some about making sure everything is perfectly dry when I open it. At times I've had to open the housing between dives to change a battery and although I do dry my hinds, I'm still in my wetsuit. I'm just careful about it and have never had a problem. Even the very few times one of my housings has leaked, I've never lost a camera housed in it.

I'm talking about video cameras and housings here, not still cameras. That may make a significant difference as still photographers have camera batteries that last much longer and may not need to open their housings as frequently.

 

[victor]

I re-seal the housing without the camera in it, recharge the camera and LCD batteries and am ready to dive again the next day.

Ops Diving with an empty housing!

 

[sphyrnidus]

My housing has a double O ring. The housing is only opened when needed, mostly to take the cam out to download the film to the computer, every other day or to charge the batteries of the LCD screen of the housing.
I leave the O rings alone as they are very hard to get out and back in is a difficult job too. I use the camera quite often as I have it with me on practically every dive, about 100 times per year. It has been fine for 2 years now.