Horological Meandering

I learned first hand why the hesalite lenses used on Omega Speedmaster Pro’s are the preffered material in space.

 

Despite being unaware of any trauma to the sapphire lens of this Zenith Prime, after carefully laying it down in the watchbox the night before I discovered in the morning that the lens had shattered. Fine shards littered to dial and I carefully carried it to the local authorised LVMH repair centre. The watch has now been repaired and the movement fully serviced, which it was in need of and the dial is undamaged.

 

Have any of you had this shattering experience before?

 

Andrew

Andrew,

Do you have any idea what could have caused such large fractures in your Zenith's sapphire crystal?  Is it a function of rapid pressure/temperature changes possibly?  I don't know how this could've happened, short of you knocking your watch with significant force, but surely you would've recalled such an occurrence?  Bizarre.  I've luckily never encountered the same phenomenon (not yet, but my watch family is still in its infancy).  The fissures in your crystal remind me of my recent car windshield issue.  A small star-shaped crack blossomed into a windshield spanning canyon due to years of temperature fluctuations.  I simply went to bed one day with an intact windshield, and awoke to a decidedly broken one.

C'est la vie!  Glad to see the Zenith is fixed and looking sharper than ever!

Daos

About 8 years ago, I checked some watches in my Luggage. They were in an unpresserized cargo hold on U.S. Air going from L.A. to Charlotte NC. The lens popped out of the case but did not shatter. It was an essentially new ETA 7560 chronograph made by Hebdomas. A beautiful watch that keeps near perfect time . The watchmaker got the lens back in and never another problem. We thought the problem may have been caused by air pressure changes. Have no other idea.

BUCKO

… If the theory is correct it suggests that the watch is impressively water (and air) tight.

 

Someone with more physics background than me might be able to work out how much the air inside a watch case would expand at 35000 feet, but personally I would be surprised if it was sufficient to ‘pop’ a crystal out. Although those baggage handlers can be pretty rough, it does sound like the most plausible explanation.

 

Perplexed,

 

Andrew

No message body

Thanks Andrew, that’s very helpful.

 

Does an expansion of 5.4 times imply an increased pressure of 5.4 atmospheres? And in practice the much lower external temperature (minus 40 to 60oC) must reduce this expansion considerably.

 

I guess that even if a watch is rated to withstand a certain pressure, the design is such that this pressure should come from the outside rather than the inside.

 

Pressure differences are still the best explanation, Watson.

 

A

...air simply leak out of the case? The pressure gradient in a watchbox in your house is going to be very shallow. Plenty of time to leak out....

Hi Daos,

 

I don’t recall any anomalous atmospheric conditions that night, or aliens hovering overhead. The kids were already asleep and, as I mentioned, I was not aware of any trauma to the crystal during the day.

 

Hopefully this is a once in a watch-collecting-life event. I will post another photo later that shows the fine shards that littered the dial; they really sparkled in the sun light. I carried the watch carefully face down to the service centre to prevent gravity allowing them to work their way into the movement.

 

A

...look for Gremlins, Andrew!

... or Poltergeist ?

As long as they wind up my watches, I don't mind.

 

That's a creepy movie!

*shivering*
Daos

you hit glass at the right spot even a small blow can cause this...

extreme temperature or pressure or frequency...could do it....

you got pissed and threw it...

somebody (dear...or not) got pissed at you and tried to hit you with something and blocked it with your watch...

the way the crack on the crystal happened, I assure you did not happen by itself and was definitely caused by an external force/object that encountered it

I hope whatever or whoever it is that hit, or caused to hit your watch is resolved. Good luck and the new SC looks good.

and the answer to your question is... it has not happened to me, either

ppcollector

… many of which made me laugh.

 

I do agree that the right blow to a crystal, perhaps if it was under pressure at one point in the mounting, could do this. Just interesting that it did not happen while on my wrist. I guess Daos’ experience with the windshield shows that this sort of thing can extend over time.

 

No fights, defensive blocks, gun recoils or golf games to explain this … but I am trying to keep my identity as a jet setting international spy a secret.

 

Andrew 008

....from the photos, so this may be completely erroneous.

But since you cannot recall whacking it on anything, it appears that the installed crystal had too much pre-load around it's perimeter (eg crystal may be marginally oversized). The appearance of the cracks (looks like inner surface was under compressive stress, outer under tensile) and the fact that they roughly follow the circumference of the crystal, would point to this.

It may be that very small or directed forces caused the pre-loaded, brittle Sapphire to stress-relieve in the form of the cracks you experienced.

Fractures from point loads (direct whacks) tend to be pretty obvious, even in formed crystals, you get the obvious star-pattern radiating out from the impact point.

 

… I don’t know what sort of stress that is, but I may be suffering from it!

 

Seriously though, I think you are right. I have been walking around with a ‘time' bomb on my wrist. That’s a very helpful explanation.

 

Andrew

My first thought was that there was some kind of resonance factor, but sounds highly improbable.  Very strange, glad all is well.  Looks  traumatic.  Very nice watch.

No message body

...(as long as she likes it...whatever! =:^D).  However, methinks whether it's sythentic sapphire, rock crystal (a la Marie Antoinette watch by Breguet), Hesalite or whatever, it can crack in many different ways by many different means.  Watch (no pun intended) that arm swinging when drinking beer and telling tall stories ("..the fish was this big... >crack!< ....uh oh...").  Enjoy!    ^_^

I once knew a girl that could suck the chrome off a trailer hitch. Don`t know what she could do to a watch crystal...?

BUCKO