Curious if anyone has any ideas on home testing for non destructive/dry water proof testing.
Have tinkered around with the skx and replaced the gaskets and seals but would like to give it a dry test before I go swimming in it, key word swimming not diving so doesn't have to be a super hard core proof.

Thank in advance OF
Isaac

 

You need two gaskets for my way
Take movement out fit gasket and screw down crown, then jump in pool no water repeat with movement in


Disclaimer- I wouldn't do it as have a no open watches rule

I would take it to a watchmaker and get it pressure tested to see how you went.

 

Hmm that's actually not a bad idea in this case, tbh.
Thanks!

 

Most of the battery replacement kiosks in shopping centres have a basic waterproof tester. I'm sure they would test it for you if you dropped them a few $$

 

OP asked for a way to dry test the watch, and these places are not likely to have that sort of equipment. They will likely have the type that suspends the watch above water under pressure, then submerges the watch and releases the pressure - these have risks. If there is a big leak that someone missed the watch can flood, crystals can blow out, etc. Just want the OP to be aware of the most likely type of testing at these places...

 

There used to be an article somewhere out there on how to make a wet pressure tester. Still requires water but you take a strong-ish clear plastic bottle with a large top (larger than a watch head). Install an air valve (automotive style) in the side close to the top. Fashion a clip to the underside of the lid to fix to a springbar. Fill the bottle half with water. Attach your empty (sealed) case to the lid. Screw on the lid and stand the bottle upright. Pressurize the bottle 30 to 70+psi. Turn over the bottle and slowly let out the air pressure. Look for bubbles coming out of your case.

Or you can buy one of these on line.........
https://www.ebay.com/itm/6-ATM-Watc...021777&hash=item1a389f29ac:g:TAYAAOSwiYlZ8sqiPurchases made through these links may earn this site a commission from the eBay Partner Network

 

Fill top load washer and then load laundry with your newly acquired 2998 -6 on wrist. Have dealers admonishment never to go near water with it on ringing in your ears as you apply hairdryer then bag of rice....Take it to a watchmaker with proper equipment.

 

The real deal. A long time ago, Bulova offered a simple tester which is shown in this link.

https://www.ebay.com/itm/X-41-WATCH...STER-IN-THE-ORIGINAL-BOX-TESTER-/362203505796Purchases made through these links may earn this site a commission from the eBay Partner Network

It uses a rubber pancake and a Petri dish. Paint the watch with liquid soap, Place it on the rubber pancake, moisten the edge of the Petri dish and place it on the pancake, then depress the lever in the base. The pancake deflects into a concave shape, reducing the air pressure under the Petri dish, and the liquid soap around any leak will bubble. This is a “shade tree” method, and I don’t recommend it as being safe on any watch you are not prepared to sacrifice. Take it somewhere and have it done properly.

 

If it had no bids at $1.99 I guess I won't be listing the one I have somewhere in my basement for sale any time soon...

 

Nor I! But who is to know? Keep yours handy, now that the world knows there is such a thing. There might be a run on them.

 

When I was a kid, the mall repair kiosks used to use a sealed chamber with a dial micrometer inside. They would place the watch in the chamber and set the micrometer on the crystal, then pressurise the chamber. If the watch was airtight (and thus watertight), then the crystal would be deflected slight inwards by the external pressure. They would then let it sit for a while, and if the gauge moved back towards zero it would indicate a slow leak.

Is this method no longer in use? Are modern crystals too rigid to deflect under a few psi?

 

Interesting device, but doesn't it test for leaks under vacuum and not under pressure? Not exactly the same thing. Maybe watches are designed to seal in both situations.

 

Yes, sort of. Here is an SMP I serviced recently and this is the pressure test after the watch was serviced:



The machine is set for the dive watch program, which checks it using a -0.7 bar vacuum (gauge pressure obviously) and then a +10 bar pressure. The machine looks at overall deflection like equipment you describe, but the type of tester with a dial indicator is a lot less sophisticated than this machine is. First thing is resolution - this is measuring the deflection to the 1000th of a micron. The machine also has parameters in it that consider the diameter of the case, how rigid the case is, the type of crystal, etc. and it is not just looking at the total deflection, but the way the case moves over time. It allows the watch to stabilize over time and then take a reading, and is looking for a particular pattern to the way the deflection moves. So back to the test - this watch passed the vacuum test, but failed the pressure test:



I use the leak finder program - this is an extended pressure test that happens over a longer period of time than the typical test does (so a few minutes rather than 45 seconds), and the deflection is watched over a longer period, and when the test is done it will tell you if it is safe to proceed to a water test or not. If the watch has been leaking, the pressure inside the case will be higher than atmosphere once the pressure is removed, and you can put the watch in a glass of water and check for bubbles to locate the leak. Took this photo as the chamber was decompressing, and it says the watch is okay to put in water - I had a glass of water standing by:



But I heard a thud just before the pressure reached zero, and when the chamber opened you can see the pressure inside the watch popped the crystal out of the case:



I suspect that whoever worked on this watch before me had used the crystal gasket over again, which is not something you should do - these hard plastic gaskets are one time use only.



I disassembled the watch and replaced the gasket:



You can see the crystal is really an interference fit with a new gasket:



Followed the two-step crystal fitting process:



Ready for another test:





Passed:



Assembled again and tested again:





Passed:



So yes the same idea is used, but in a much more modern way.

​

So yes, of course watches are designed to seal in both situations - positive and negative pressure. Since the watch is sealed (hopefully) any time it warms up relative to the temperature it was when it was sealed there will be some internal pressure. I've seen domed mineral crystals actually break just by being worn in the sun on a hot summer day - managed to find photos of this one I remember from about 10 years ago where the owner was at a baseball game in the sun, and was actually looking at the watch when the crystal snapped - that's one reason I remember this one so well with freak timing:



I've also know that on some cheap watches the crystals have popped out while people are flying in planes. But this same type of failure can happen with the machine that @redpcar posted above - you pressurize the watch above the water line, then release the pressure and submerge it - the crystal can pop out and flood the watch, which is why watch manufacturer's require a dry testing system like I have.

But the vacuum test in my view is a more useful "everyday" test than a pressure test. Pressure on the crystal, crown, etc. can actually help seal a watch so the vacuum test will give you a better idea of how the watch performs when it gets splashed while washing your hands, or when you get caught in the rain, etc.

Ideally you would do both, but in a pinch the vacuum test will tell you if the watch can sustain incidental water exposure.

Cheers, Al

 

Thanks, Al. I'm gonna guess that tester isn't something that one would find on Fleabay for a couple of hundred bucks.

 

Regular calibration costs more than that...so no this isn't a hobbyist type purchase. BTW not shown is the compressor that goes with the machine...

 

How often does it need to be calibrated?

 

I used to do profilometry when I was a process engineer in the semiconductor industry. I have a question about the Witschi : out curiosity, does it use contact (stylus) or non-contact (optical) means to measure deflection?

P.S. Awesome post BTW.

 

Okay realize now I made a typo - it's to the 100th of a micron...but hey what's an order of magnitude between friends!

On the sensor, there is physical contact between the sensor head and the watch crystal. I don't know what is inside the sensor head though as it's a sealed unit that gets exchanged if there is a fault (had to do that once). It has a pretty wide range because the deflection on some watches is pretty large - in particular with acrylic crystals you will see deflection close to a mm in some cases.

 

Which begs the question, how often if at all - do crystals fail due to fatigue. If someone was doing a lot of repetitive diving - say a divemaster who's dropping in two or three times every day - is it possible that the crystal may develop a stress fracture and fail, not unlike the ill-fated DeHavilland Comet?

 

Stress cracks do happen certainly on acrylic crystals, but it's not something that is really all that common with the watches I see in my shop. I can't say if those are from cycling of pressures or just degradation of the material over time though, or a combination of both.

My feeling is that most crystals would get replaced due to scratches or impact failures before the stress cracks form.