Pressure test and troubleshooting

[bvbellomo 0]

I bought a used 6300 Nauticam housing, but was disappointed that it leaked on my trip.  It does not leak at surface pressure - even 48 hours in a bucket randomly pushing buttons, but it leaks right away below about 60 feet.  Nauticam offers a full overhaul, including "pressure testing" if I ship the housing back to them, and I may go that route.  But I wondered if there was a way to pressure test this at home?  Obviously throwing it until a pressure cooker is a bad idea, but there should be some sort of vessel I can buy and pressurize with a pump.  Any ideas?

Edited November 15, 2021 by bvbellomo
typo

[TimG 62]

Hi bvbellomo

If you fit a vacuum valve that will give you an indication on the surface if a housing is leaking - although, if course, it does not tell you why!

Lots of WP members use them and the Vivid Leak Sentinel is popular (I've had one for years). Have a look at:

https://www.vividhousings.com/leak-sentinel.php

 

[bvbellomo 0]

Either I misunderstand what this device is, or it is the same thing Nauticam already has built into the housing.  The housing does not leak at surface pressures.

I imagined using something like a pressure cooker with a bicycle valve, fill it 3/4 with water, and add air until around 30 psi.  I could probably make something like this, but for far more money and time than just having the housing rebuilt.

Edited November 15, 2021 by bvbellomo

[TimG 62]

Ok, right, yep, if you have one built in to your housing, then it's pretty much the same thing.

My moderator colleague, Chris Ross, is a whizz on pressure issues and calculations and can probably tell you how you might be able to do it. Chis is in Australia so you'll have to hang on till he's up and about....

Curious though that you don't get any kind of leak indicator at the surface when pressurised using the leak detector. Normally as you get deeper the seals improve. This leads me to think that perhaps there is salt on one of the control buttons and the depth is just putting sufficient additional pressure to unseat the control slightly and the salt build-up is preventing a compete seal.

If the device you suggest can be made to work  you could stuff the housing with, say, toilet paper and see where the leak is.

I'm not sure what it would cost to cobble something together, but getting a housing serviced sure does not come cheap if you have to send it to a dealer.

[Kraken de Mabini 204]

Some suggestions to locate the housing's leak:

 

1. Inspect all O rings and grooves, ports and back cover, for defects and dirt.

 

2. Buy a vacuum leak detector from Miso, install it.  To locate a small leak, this might work: Stuff the housing with balled up newspaper, establish a vacuum, sink housing in bucket for 1 or 2 days, hopefully the newspaper will help locate the leak site. 

Sinking the housing in a swimming pool will be better.

 

3, inspect housing closely to see if you can take the buttons, etc. apart. Nauticam housings are famous for being difficult in this regard.  

 

4. Send it to a qualified repair shop: Nauticam, Reef Photo, Backscatter.

 

or better still:

 

Ask the guy you bought the housing from for a refund.

 

Good luck and let us know the outcome.

-
Reference:  https://wetpixel.com/forums/index.php?/topic/66474-vivid-vacuum-leak-detector-some-comments/

 

[bvbellomo 0]

I'm familiar with  Chris Ross and will wait for his advice, especially if the alternative is over $500 and over a month's wait.

If I had a good deep place to dive, stuffing it full of toilet paper and going to 60+ feet would probably work.  In Ohio, quarry diving is miserable until April and they probably aren't deep enough anyway.  I planned to try this summer but never got the chance.

I completely fail to understand the physics here.  If it leaks immediately at 60 feet with very little vacuum, and that a pressure difference of 30psi, then it should leak immediately with 30psi of vacuum on the surface, right?  Maybe the Nauticam pump isn't strong enough to pull 30psi, but their are no leaks with the strongest vacuum I can get for 48 hours but it leaks in 5 minutes every time 60 feet down with normal use.

[TimG 62]

1 hour ago, bvbellomo said:

I completely fail to understand the physics here.

Yeah, I'm with you. If it's ok at the surface it should be ok at 60' - better than ok! Something ain't right (doh!)

It the meantime it may well be worth trying what Kraken de Mabini suggests at 2 with the newspaper and bucket routine. You've got the vacuum detector already. That's the route I'd be going next. 

 

[Tom_Kline 143]

The theoretical maximum pressure differential one can test for at surface pressure with a vacuum device is 1 atmosphere (bar) - that would involve pulling a complete vacuum inside the housing. The most I have done is ~0.5 atmospheres (atm) by pulling down the vacuum to -15 inches of mercury (these are the calibrations on my analog gauge). This takes a bit of work (many pulls that get harder to do as the vacuum gets better) - I have only done this after having removed the port in the field (up a creek in my case). SOP for me is -10" so I pull about 1/3 atm thus there is just 2/3 of an atm pressure for leak testing purposes. I mainly use this amount to squeeze the O-rings a bit (thus putting them to work) for shooting in very shallow water.

As it sounds like you needed to have close to 2 atm to get a leak (assuming you had 1 atm inside the housing), it will not be possible to do at the surface. BTW most pressure cookers have a pressure relief valve so that may not work. As well one needs to be very cautious about pressurizing a container because at some point it will explode launching bits of metal in various directions. Extreme caution is advised. There are professional testing facilities for this sort of thing. By far the cheapest way of pressure testing is to take the housing on a dive without the camera inside (but have a weight (I use soft ankle weights) inside instead unless you want to tote around a balloon).

Edited November 15, 2021 by Tom_Kline

[ChrisRoss 150]

Most vacuum systems can only achieve relatively light pressures, the Nauticam system the light goes green at about 200 mbar of vacuum and as Tom says the max vacuum achievable of one bar or 14.7 psi and you won't get close to that with the little hand vacuum pumps no matter how much you pump.   The vacuum system works by seating the o-rings against the o-ring grooves and it needs time for enough gas to leak in for the system to detect it.

Have you already pulled a vacuum on the system and then left it to sit for an extended period - like 2-3 days?

If it has passed that test then it is likely to be a damaged or twisted o-ring that can seal against lighter pressures but higher pressures cause it to flex inwards and let water in.  There was a guy on here who was having similar problems, might have been in the last year or so who ended up sending the housing in.  You might PM him to see the result, this is the thread:

Before you do that I would I would suggest you take out both the back and port o-rings and critically examine them for cuts, splits abrasion etc using magnification to see any possible damage.  They should be perfectly smooth apart from a thin line of material from the moulding process.   Run them through your fingers as well. 

[josemuelledes 1]

Look at this solution by glowdive, in spain. 
 

Edited November 16, 2021 by josemuelledes
more information

[Kraken de Mabini 204]

Excellent video, the housing is surrounded by compressed air at 4 or 5 atm, the compressed air enters the housing through the leak(s), the housing is submerged and the bubbles can be seen.  Only problem is finding somebody with this pressure chamber.

Or one can first replace all readily available O rings, then substitute time for pressure and use a swimming pool: Put a soft weight in the housing, remove batteries, stuff it with soft paper, tie a line to it and sink it for several hours, or a day or two if needed, in the deep end of a swimming pool, and see if the leak shows. 

  

[Marc Furth 3]

I make my own housings and test them in a used pool filters. You can use regular city water pressure and simulate a depth of over 150 feet depending on you water pressure. It's much safer than using air pressure.

Edited November 17, 2021 by Marc Furth

[phxazcraig 123]

Guessing here, but if the leak detector doesn't show a leak after 48 hours, then I think there actually was no leak at the surface.

Which means something changed at depth, and I'm thinking that means that the pressure was enough to depress one of the buttons a bit.  And that button has a defective seal that only shows up when it is depressed.

Which would mean that it might be possible to find the leak at the surface by carefully holding in one button after another and looking for leak detection.  Obviously this might take a long time - but perhaps might just show up almost as soon as the problem button is held down a few seconds.

Another, seemingly unlikely, scenario would be the housing itself deflecting under pressure.

[TimG 62]

35 minutes ago, phxazcraig said:

Which means something changed at depth, and I'm thinking that means that the pressure was enough to depress one of the buttons a bit.  And that button has a defective seal that only shows up when it is depressed.

Yeah, that was my hunch too.

[Davide DB 608]

Here's my horror story,

Friday evening my buddy and I closed the housings and turned on the leak detector which indicated a nice green light.

Saturday we go down on 70 meters and he photographs two sunfish and then a dogfish shark. Then he hears some tik tik tik and thinks it's the computer. He encounters another dogfish, goes to shoot and realizes he has water in the housing. We abort the dive but in less than a minute the case is full of water.

At home at night I still have the green leak detector light on. I still have the batteries full and am considering leaving everything as is. Then I turn on the monitor to show a clip and realize it's not working.... I think the HDMI cable came off, so I open it up and WTF I find a bit of water (salty) in the monitor case but all dry in the camera housing. Monitor saved but the internal flat hdmi cable is broken.
Since the camera and monitor housing are connected and make up a single vacuum assembly, I can't figure out how it happened.

To conclude: one of those weekends that it was better to stay home on the couch and watch the soccer game.

[TimG 62]

42 minutes ago, Davide DB said:

To conclude: one of those weekends that it was better to stay home on the couch and watch the soccer game.

Really. And hide behind the sofa.

[scubateacher 0]

Hi if you put a Schreder valve in the housing thur the vacuum hole. Then apply as much pressure inside the housing as you need from a pump. If you try this you have to let everyone know how it works. 

[ChrisRoss 150]

9 hours ago, scubateacher said:

Hi if you put a Schreder valve in the housing thur the vacuum hole. Then apply as much pressure inside the housing as you need from a pump. If you try this you have to let everyone know how it works. 

You can but I wouldn't - housings are designed for external pressure.  You can test with internal pressure but things like to port, viewfinder and LCD screen window may not be designed to handle internal pressure. 

A viewfinder like on the Nauticam housing has metal to metal contact when external pressure is pushing the viewfinder into the housing.  But inside it uses an o-ring which is the only thing stopping the viewfinder popping out and it it will be rated to a lot less pressure difference than the metal to metal contact you have when the pressure difference is external.

A bigger problem is the housing back, the forces on that are significant due to the larger surface area.  The force acting on my housing back which is  4.3 x 6.3 inches approx at one bar internal pressure would be equivalent to 390 pounds and the only thing holding it closed is a plastic latch on the side.  This is absolutely fine with external pressure as the back has metal to metal contact with the housing rim which supports that pressure.  If you put one bar of pressure inside the housing it would probably blow the back off with some force.  The bigger the housing the bigger the force acting.

In short DO NOT pressurise a housing internally it's not designed for it and it potentially dangerous.

 

 

[PeteAtkinson 53]

If you have access to a lake or the sea I would put weight in the housing so it sinks, stuff it with toilet paper so you see where it leaks and lower it 20m on a rope. Not too long in the first instance.

[Davide DB 608]

12 hours ago, ChrisRoss said:

You can but I wouldn't - housings are designed for external pressure.  You can test with internal pressure but things like to port, viewfinder and LCD screen window may not be designed to handle internal pressure. 

A viewfinder like on the Nauticam housing has metal to metal contact when external pressure is pushing the viewfinder into the housing.  But inside it uses an o-ring which is the only thing stopping the viewfinder popping out and it it will be rated to a lot less pressure difference than the metal to metal contact you have when the pressure difference is external.

A bigger problem is the housing back, the forces on that are significant due to the larger surface area.  The force acting on my housing back which is  4.3 x 6.3 inches approx at one bar internal pressure would be equivalent to 390 pounds and the only thing holding it closed is a plastic latch on the side.  This is absolutely fine with external pressure as the back has metal to metal contact with the housing rim which supports that pressure.  If you put one bar of pressure inside the housing it would probably blow the back off with some force.  The bigger the housing the bigger the force acting.

In short DO NOT pressurise a housing internally it's not designed for it and it potentially dangerous.

 

 

I completely agree with you.

P.S.

Many years ago I remember of a monster cinema 35 mm film camera housing having a Schreder valve as leaking test system. It worked applying a positive pressure inside the housing. But actually it was a completely different design with metal screw closing system. It was built like a tank.