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  1. ScubaPro Actually dives with dive watches!!! Nov 1, 2016

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    I've always wondered if you get a full service on a watch (especially a dive watch) with a display back do they replace a seal similar to the crystal or is the display element more permanently sealed into the back? Anyone know of a display back ever leaking?
     
  2. Canuck Nov 1, 2016

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    Does anyone produce a serious diver's watch with a display back? I'd be a bit afraid of the glass back popping out during a water resist test!
     
  3. Archer Omega Qualified Watchmaker Nov 1, 2016

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    ::facepalm1::

    New PO's have a display back and are rated to 600m mate...so yes the brand is the main one on this forum...
     
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  4. Archer Omega Qualified Watchmaker Nov 1, 2016

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    Of course when servicing the case back gasket (rubber O-ring in most cases) is replaced. There is a seal between the sapphire crystal in the display back and the case back, and it is a hard plastic seal similar to the one that holds the front crystal in place. These are one use only items, so once you press the crystal into the case and deform that seal, if you remove the crystal you must use a new seal.

    Typically a brand will remove everything from the case when they do a service, so I know for sure they remove the front crystal, and I would assume they remove the back crystal - this is primarily because they are doing their typical complete refinish of all case surfaces though, and not because the seal itself really needs to be replaced at each service.

    If a seal around a crystal is leaking it's likely due to poor installation rather than a breakdown of the seal itself. With thick crystals used in dive watches in particular, the gaskets can be pretty tall, and any misalignment while pressing the crystal in will damage the seal and you have to start over. A good sturdy rack press like this one is best for pressing in these crystals...

    [​IMG]

    [​IMG]

    And of course the proper 2-step technique is used for fitting these crystals...

    Cheers, Al
     
  5. Canuck Nov 1, 2016

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    In my Post, perhaps you missed the word SERIOUS in italics? If you were a serious commercial diver, would you wear a "diver's" watch tarted up with a glass back? It was an honest question! Thanks for your flip answer!
     
    Edited Nov 1, 2016
  6. Vercingetorix Spam Risk Nov 1, 2016

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    Omega replaced the rear crystal gasket on my Solar Impulse last time they had it.
     
  7. Archer Omega Qualified Watchmaker Nov 1, 2016

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    You! Are! Welcome! Seriously! ;)
     
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  8. ScubaPro Actually dives with dive watches!!! Nov 1, 2016

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    I've always wondered about this, and while I thought there might be a way to seal the rear crystal in more permanently but I never thought about refinishing the case back and I guess you would need to remove the "glass". Besides, you do have two completely different materials pressed together so you would need a gasket since they would react differently during pressure and temperature changes. I've noticed the latest crystal seals on dive watches seem to be of the "L" shaped delrin variety and really tough, but are no good once disturbed. Another thing for the watchmaker to deal with during a full overhaul, but very reliable once properly installed. Thanks Archer-
     
  9. Archer Omega Qualified Watchmaker Nov 1, 2016

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    Omega doesn't typically use L-shaped cross sections for their crystal gaskets. They use a rectangular cross section, often with an internal bevel as you see here:

    [​IMG]

    There are many ways of holding a crystal made of a rigid material in place - they can be friction fitted like the old glass pocket watch crystals are, or they could be glued in place like you would with a vintage fancy wrist watch crystal, but most modern watches use a gasket of some kind. This kind of gasket is used in watches with extreme depth ratings, so even a "serious" dive watch like this Sinn U2 I have in the shop right now that's rated for 2,000 m depth...

    [​IMG]

    If I look at a new PO, rated for 600m, the gaskets for the front and back crystals are identical other than their diameters - both are like the one I show above so rectangular profile with leading bevel, and both are 1.6 mm high for the thick crystals involved. So if a gasket can hold the front crystal in place, obviously it can hold the back crystal in place.

    Cheers, Al
     
  10. w.finkenstaedt Nov 1, 2016

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    I know a couple commercial divers that wear Omega's as their primary dive watch, one who wears a Blancpain Bathyscaphe (again, crystal back).

    Just because you don't consider them "serious" dive watches doesn't mean they aren't used that way. These guys all have them insured on their homeowner's policy or a separate jewelers policy and don't hesitate to use them for what they're intended for.

    From talking to them, the Omegas and Blancpain all perform way better than other backups they've had (Seiko, older Rolex, Sinn, etc).


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