Water testing watch dangers

[mikesomething]

I was thinking that if we were to do a wet test, if the watch has pressurised air in it, when we depressurise, is it possible the glass could get pushed out?

also, say you tape the crown down on a basic watch, wouldnt the tape invalidate the test, as in the real world the watch wont have the tape present?

 

 

[szbalogh]

3 minutes ago, mikesomething said:

I was thinking that if we were to do a wet test, if the watch has pressurised air in it, when we depressurise, is it possible the glass could get pushed out?

also, say you tape the crown down on a basic watch, wouldnt the tape invalidate the test, as in the real world the watch wont have the tape present?

 

 

You depressurize it slowly. As slow as pressurizing. This way as much air went in so much will come out while depressurizing. Basically there is no difference in the pressure if there is a leak. If no leak then the internal pressure is lower.

Taping the crown? Why?

[jdm]

1 hour ago, szbalogh said:

You depressurize it slowly. As slow as pressurizing.

Yes. But in cheap testers the pressurization is always relatively slow since the pump is operated by hand, instead the depressurization is done with a quite crude valve, so it's easy to let air out too fast. Some risk exists.

[clockboy]

I have not encountered any crystal problems when pressure testing watches. My method is I test the watch case first before progressing with another test with the movement installed. If a crystal was to pop out then it is either not fitted correctly or the wrong size crystal case been fitted. 

[parmenion31]

i had a crystal poped out but the watch case was plastic.

[SSTEEL]

• Ive had a crystal and bezel pop off whilst depressurising, and for this very reason, I always remove the movement, and only test the mid-case of a watch.

[clockboy]

Interesting were the watches designed to be waterproof. I never test watches that are sold as water resistant only waterproof watches,Rolex,Omega, Seiko Diver etc. I don't know of a waterproof plastic watch.

[jdm]

1 hour ago, clockboy said:

I don't know of a waterproof plastic watch.

One example is the Casio G-shock, 200m certified diver's http://world.g-shock.com/asia-mea/en/technology/water-resist/

[jdm]

2 hours ago, SSTEEL said:

• Ive had a crystal and bezel pop off whilst depressurising, and for this very reason, I always remove the movement, and only test the mid-case of a watch.

This way you won't know if (for example), the back gasket has not seated perfectly after installing the mov.t, and there is potential water ingress. Unfortunately there is no replacement for testing the complete watch, but as mentioned, decompress very slowly.

[Ishima]

It's not unheard of, but I think it's usually a case of careless testing. It only happened to me once after I pulled the watch out of the water and in my haste let the valve off a little bit more so I could get the watch out and go about my work quicker, so luckily no real harm there done.

I was trained to follow these rules. 
after pressurizing, wait 1 minute per bar of pressure before beginning the test, so that in the event of a leak, the pressure is equal and water won't get in easily. Let the valve off slowly as has been mentioned, so that the pressure behind the glass isn't excessive. Keep a hand on the valve ready to adjust if needed. Make your decision on a pass/fail and pull the watch up before the pressure needle hits 0. (usually I do this just before the needle hits +1 atm). The exception to that rule, where I'd let it go completely down to zero submerged is if I do a case only test, which I only do with screw down crown watches, as I don't believe taping the crown down is the same as it normally would be. Also if you do notice a stream of bubbles that indicate a leak, don't leave it for a second longer than you need to to get the information/confirmation you need, remove the watch from the water and end the test. (again an exception if it's case only, no need for that precaution) 

Oh and this won't apply to many but if you have one of those basic vacuum testers as well, it's usually worth doing that quick test first, so that you can either take a clear pass result from that at face value and not wet test, take another look at the watches sealing if the result wasn't good, before wet testing. Or at least just be prepared for the fact that it's going to leak and you're testing to find where the leak is. 

Edited August 23, 2017 by Ishima

[SSTEEL]

53 minutes ago, jdm said:

This way you won't know if (for example), the back gasket has not seated perfectly after installing the mov.t, and there is potential water ingress. Unfortunately there is no replacement for testing the complete watch, but as mentioned, decompress very slowly.

Once I know a case is waterproof, I then carry out a final test again, this time with the movement fitted.

[jdm]

29 minutes ago, SSTEEL said:

Once I know a case is waterproof, I then carry out a final test again, this time with the movement fitted.

A matter of preference, To me, doing that way makes me spending more time, and more chances that something can go wrong wit the extra manipulation. A quality watch is OK being tested once, with the precaution already mentioned above: depressurize slowly, and stop at the first indication of leak.

Edited August 23, 2017 by jdm

[SSTEEL]

Spending more time carrying out a secondary test is no problem for me, I supply videos of the test too for some customers.

[Ishima]

On 8/24/2017 at 8:22 AM, SSTEEL said:

Spending more time carrying out a secondary test is no problem for me, I supply videos of the test too for some customers.

 

I can see that being a problem.  Get those little pockets of air trapped in the bezel or what have you and end up having to go through this lengthy explanation and maybe they don't believe you and ergh. Would be a big problem for me at least, most of the time I just need to get the jobs done, serve the customers efficiently and get back to the workbench.

As a tangent though, I am guilty of occasionally being a bit too transparent with customers in other ways though. For example, a lot of people tell them "You open a watch and it breaks the seal" well that isn't really accurate, so If a customer tells me they've been told that I usually explain the full nature of resealing instead of using the quick and easy white lie. The problem being I'm rarely sure whether they're less assured or more. I just don't want to lie both because it makes me uncomfortable and because of that adage about "the truth being easier to remember" you don't end up contradicting yourself.