I'll try "Crystal Thickness" for $400 Alex....

Forumers,

Doing some research in the archives and found 1/2 the answer to my question from a post by Cellar (Sept. 5, 2007).

Does anyone know the crystal thickness of the VC-AT vs. the AT2000's(4.3mm)?

Thanks for any assistance,

Andy

Hi Andy,
The AT-VC (3231) front crystal is 2.20mm thick.
From lower edge to the top of the dome it is 3.50mm in height.
The GST-AT (3536) crystal is 3.70mm thick.
Leo

Great topic! Any info maybe about the crystal of the youngest Aquatimer Chrono ref. 3767?
I semm to remember a back issue of the Watch International where the Fliegerchrono 3706 was mentioned to have a crystal 0.8 mm thickness and this was mentioned as thick... I'm not sure to remember correctly though. As I have this issue somewhere I can look after this info when I'll be back from holidays (on my wrist my Cousteau chrono 376706...)
Best,
Robert

Hi Robert,
The 3767 crystal is 2.50mm thick.
The 3706, 1.40mm
Leo

Leo,

Thank you so much for taking the time to verify the "crystal thickness" of the VC-AT.

I'm curious...is there some reference you use that is available to Forumers for future inquiries?

Again, many thanks....Andy

Hi Andy,
I have been the head watchmaker/manager of the IWC-UK workshops since 1999 but the precision, rather than experience, required in response to your 'thickness' question had me referring to our internal intranet database.
I thought someone might pick me up on it, knowing, as a fellow forumer, the thirst for more IWC knowledge held by forum members.
Although not quite'Top Secret', it obviously can't be accessed by, or published for, the general public (or unfortunately Forumers).
That said, I am more than happy to offer replies (within reason) that require access to the database through the normal forum.
Leo

Leo,

I can only imagine the wealth of information you have acquired as a watchmaker along with your capacity for IWC. I fully understand the restricted access of the companies proprietary database and appreciate your invitation to help answer (reasonable) questions from fellow Forumers.

Over the last 18 months, the "virus" has done a number on me and my wallet. My appetite for learning specific details about each new model added to the collection has been one of the "side effects" of the infection. However, I must admit, wearing IWC watches is just part of the enjoyment. Understanding the history, specifications and method of construction
adds to the overall satisfaction of owning the IWC luxury experience.

Thank you Leo for offering your expertise to the Forum. The contributions from the many "seasoned" members make this site the go-to for the most accurate, up to date and reliable information about IWC.

Regards,

Andy

@ Leo, I guess you know that us fellow forumers really do appreciate your inputs and responces. Knowledge held by Watchmakers like yourself and Jack are of great importance to ensure our questions are answered - and we really are thankful for that.

Hi Leo,

just reading again my Watch International back issues, in the 1/96 issue I've found a data the Fliegerchronograph having 1.8 mm thick crystal. This does not mean necessarily that one of the two data is wrong, maybe IWC thinned down the thickness as the watch has to withstand only 6 atm pressure. The 1.8 mm data comes from the earliest days of the Fliegerchrono production, that was introduced in 1994.
I've posted this only as an interesting addition.

Best,
Robert

Hi Leo,
When crystals are replaced for the Aquatimer during a complete service, do they get oven baked when the epoxy is reapplied for the new crystal? Would it be possible for you to elucidate the process of crystal replacement, particularly for the AT range?

Furthermore, does each professional Aquatimer (2000m rated) go through pressure tests again to the specified rating (i.e. 2000m) as part of the complete service?

Your insights are very much appreciated.

Hi Leon,
The only Aquatimer with a baked-in fitting was the GST 3536. All others since, from 3538 to the current 3769, have the crystals friction fitted with Hytrel gaskets. The equipment for fitting the 3536 crystals is very specalized so this model is now always returned to the factory for servicing.
The proceedure for fitting crystals with gaskets is relatively simple.
The model specific synthetic case support and crystal die made by IWC are attached to a hand-operated press or potence, the case and crystal are inserted and carefully aligned and the press operated, driving the crystal into place while compressing the gasket.
The watches are tested to their stated depth during manufacture to verify the strength of the case and components at that depth.
During service they are tested to 10bar. As per the factory, this is more than enough to guarantee the continued water resistancy to the depth the watch is designed for. This is possible as the extreme thickness of the caseback and crystal prevent the watch from compressing by no more than a few microms at depth.
As an extra security measure, the watch is also tested at a negative pressure of -0.5 bar to simulate the possible forces experienced when first entering the water.
Leo

Excellent reply with great insights. Thank you Leo. Really appreciate your time.

Hi Leo,

You really have inside kowledge, thank you very much.

I have a question I asked once or twice here without really getting an answer. The Pilot's watches have a crystal construction to prevent the crystal to pop out when having an air pressure dip. How does this work? Is this construction only reserved for the Pilot's watches? About a year ago there was a member mentioning that the crystal of his Portuguese popped out while flying: not a nice experience. I could imagine that all the watches of IWC would have satisfactory anti-pop-out provisions, are those of the Pilot's watches different, better? Thank you for your answer.

Kind regards,
Paul

Hi Leo,
Sorry to trouble you again, but what are the pros and cons of the oven-baked crystal fitting (as per the GST 3536) vs. the less sophisticated friction-fitted process (as per the more recent models)?

There must be reasons as to why IWC has discontinued the previous approach (i.e. costs, time, failure wear & tear risks, temperature fluctuation intolerance?)

I really appreciate your experienced insights.

Cheers,
Leon.

Fascinating thread. Should I keep an elastplast over my 3536 crystal, just in case?

Hi Paul,
The factory has never issued any technical information to the service centers regarding the 'pop-out' resistance of pilot's crystals. After reading your question, I looked in to it but only found a short mention in the MKXVII manual.
Without official confirmation, this is my hypothesis:
Although both pilots and 'normal' models have the crystals pressure fitted to the case form the front, the seating of the seal is very different.
On a 'normal' model the seal sits on a 'L' shaped ledge with the top exposed.
On IWC pilots models the seal sits in a 'C' shaped groove with no exposed facets.
This encased seal should offer more security as it has nowhere to expand to when compressed by the crystal.
Pilots models are tested to 0.5Bar (50% less than sea-level pressure) but most airliners have a minimum pressure of 0.75Bar (25% less than sea-level) so your pilots watch can handle at least double the negative pressure normally experienced.
Older models negated these problems by fitting a stepped plexiglass from the inside of the case such as 3740 Qz Chrono or MKII.
Leo

Hi Leo,

It is great to read your answer, and to see that there is much more here than meets the normal eye. Thank you very much for looking into it, to take this trouble, and to write about it.

Kind regards,
Paul

Hi Leon,
IWC's previous 200bar watch was the PD Ocean 2000. It was produced for about 4 years under the references 3500 3504 and 3524. The crystal seal composition at the time could not be guaranteed to withstand these depths, unlike the Hytrel gaskets now used. Many of the adhesives available at the time could not withstand the depths either and more importantly could not withstand the changes of temperature experienced. The kiln cured adhesive was found to offer security in all conditions.
The 3536 used this method as it was well proven and the factory was already setup for this type of production. The crystals(and other components like the bezel gearing) are interchangeable on both PD and GST.
The change to gasket fitted crystals is a further example of IWC utilising the latest technological advances in their watches. The production costs must be significantly lower for the same level of quality and the watches can now be serviced and resealed in your local IWC service center rather than having to be returned to Switzerland.
Leo
P.S. for Rave
You can safely take off the bandage. In 15 years of working on IWC's, I have Never seen a 3500 or 3536 leak through the crystal setting.

Excellent insights as always. This is why I love IWC. Your transparency and fanboy engagement as a luxury watch company is second to none. I'm so proud to be a 3536 owner. Many thanks Leo.

Leo,

Hope you're well.
How thick is the crystal for the GST Perpetual Calendar/chronograph? I can't find any info on this. It'll be great to know.

Many thanks.

Hi Leon,
It is 2.5mm thick,38mm diameter.
Great watch....
Leo

What a fantastic thread..........

These shores may not have our own Boutique and AD's are getting thinner and thinner in the UK, with the closure of Airport concessions very shortly. London City Airport are forced to cease their IWC range end of next month. I will check with the CEO of Mappin & Webb when the likes of their Heathrow T5 concession may close......:((.

On a more positive note it looks like the UK has the best, informative and co-operative Service Manager on this planet. Big pilot strap thread is another good example.

So for all those UK travellers grab your duty free bargains before it is too late, the window is nearly closed :((((

Regards

Mark

Thanks Leo.

It's great to be able to talk to an actual watch maker.

And thanks MRP. The closure of UK duty free concessions are news to me.

I am pleased to report that it is only the London City Airport that will cease in terms of its IWC offerings at the end of March 2013. Heathrow via Other outlets survive.