For my buddy Stas...and anyone else who may be interested, even though they don't dive...

I didn't want to post anything until I found these photos...but I knew I had tested at least one of these before, so after some digging, here you go. I'll start off by stating this is the second time the case was tested, because all of what you will see here is done with the case empty first, in case there is a failure. Then once the empty case passes, the movement is installed, and the test is repeated, so this is that second test. Start by using the dry testing machine, set to the dive watch program - it will use a -0.7 bar vacuum, and then a +10 bar pressure to test the watch, while carefully measuring the deflection of the case:



The watch passes both tests:



Now off to another room where the high pressure wet testing equipment is located:



The watch is placed in the testing chamber, and the chamber is filled with water:



The chamber is closed, and the watch is left with no additional pressure applied for 30 minutes - note that I hadn't wound the watch, so it wasn't running:



After 30 minutes the pressure is increased. This particular equipment is capable of testing to 125 Bar, but that is for very rigid dive watches with thick sapphire crystals. In this case I used 25 Bar, so 200 m rated depth +25% safety margin as per Omega standards for this kind of testing of their proper dive watches - here is the pressure gauge:



Shot of the watch in the chamber and you can see the pressure gauge also:



I leave it at this pressure for one hour, then lower the pressure back down to zero, and leave it in the chamber for another 30 minutes:



The watch is then removed from the testing chamber:



Placed on a heating plate that will bring the temperature of the watch to 47 degrees C - this takes 30 minutes:



After 30 minutes have elapsed, a drop of cool water is placed on the crystal, and left for one minute:



It is then wiped away, and the crystal is examined under a loupe to ensure that no condensation has formed on the underside - seeing none, the watch has passed:



et voilà

Cheers, Al

 

Thanks for posting, great step by step

 

If many more watchmakers posted all these useful photos and information there would be many other "watchmakers" out of a job...

 

Damn...I always wondered what was behind the curtain of a pressure test. Thanks!

 

Very interesting, I didn't know the last test with the cool water drop to check for condensation

Is this full test also performed with modern WR non diver watches?

 

For those that often complain at the costs of having a watch properly serviced and tested just imagine what this little piece of kit costs and then add all the other essentials to carry out the job properly.

Nice post

 

Very cool, thank you for sharing!

 

Always wondered about these tests. Thanks!

 

All watches get the dry pressure testing, and Omega uses the wet test for any watch that is rated for 120 meters or more, and has a screw down case back.

Cheers, Al

 

Stupid question I guess but how do you address a fail?

 

Identify and fix the leak if possible. How that's done depends on where the leak is. It can include things like changing the case tube, crown, case back seals, crystal seals or crystal, pushers if it's a chronograph, etc. Note that in most cases, if someone was that concerned about water resistance that they wanted it tested to this level, I would have already replaced those items.

If there is a whack of corrosion on the sealing surfaces for example, then that would require delicate work like laser welding of the O-ring groove in the case, then recutting that groove. Of similar kinds of repairs to the case back...I don't personally do this kind of repair. I'ce actually never been asked to do it either...

Cheers, Al

 

Very cool! This certainly raises my confidence in the integrity of these watches. Although I've heard that you're not supposed to do more than shower with a non-sport watch rated for, say, 30 meters, it's good to know that Omega (and Rolex, and a number of others) take the rating literally - if it says 300 meters, then by God they mean 300 meters! (As long as you get it pressure tested regularly!)

Thanks so much for the explanation!

 

Wow Al,
Just to be clear, when the chamber is filled with water and pressurized a blowout would fill the case with water.
For some reason I thought it risky to compromise the watch components and dial, you must be confident in your work
I've seen pressure testing done elsewhere without the guts of the watch just to test the case and caseback.
How is it done at the manufacture?

 

Thanks for the inside look. Very cool.

 

thanks for sharing yet another interesting insight into proper watch making/servicing...

 

If you read my opening paragraph in the first post...

"I'll start off by stating this is the second time the case was tested, because all of what you will see here is done with the case empty first, in case there is a failure. Then once the empty case passes, the movement is installed, and the test is repeated, so this is that second test."

There is obviously risk in this procedure, but before I get to this stage the empty case has been through the dry test, then the complete wet test, then the movement is installed and been through another dry test - so 3 pressure tests have been done to this stage before I do the last one. I can't eliminate 100% of the risk, but I eliminate as much as I can.

And yes, I've had failures...



But again the case was empty and on the first test when this happened:



Not something I could control in this case, as the crystal must have had a weak spot in it. I always check for a heavy scratch or chunk out of the crystal and didn't see any on this, so it was some sort of internal flaw in the sapphire, because I have pressure tested plenty of this model of Panerai and not had failures before. I was in another room adjacent to the pressure testing area when this happened, and about 20 minutes into the hour long high pressure portion of the test (at 37.5 bar) I heard a very loud "tink" sound, and even though this was the first time this has ever happened to me, I knew immediately what the sound was...

Watches are tested the same way at the factory, but in a machine that can accommodate more than 1 watch at a time of course. To be a proper dive watch, you can't just sample a batch - every watch has to be checked individually.

Cheers, Al

 

This is really interesting - I had never really thought about how it was done.

Have you ever had a watch (or most likely a crystal) crack which in the pressure chamber?

Edit - answered above

 

Sorry my watch testing equipment doesn't meet your expectations. However it is approved by Omega...listed as acceptable (along with Roxer brand) in Omega Work Instruction 22.

Cheers, Al

 

Okay...considering the most water the majority of these will ever see is washing hands, rain, or splashing in a pool, I doubt it makes a big difference if a 600 m rated PO is off on the pressure test by a few meters...

 

Good thing there is also a 25% FS...