Pressure Test Results

[marblegranite]

I had my Chopard MM GTXL Chrono pressure tested today to make sure I can swim with it. According to the TD's website this watch is supposed to be water proof up to 30m. They performed a total of 6 tests (2 at a time). The watch failed on a couple of tests.

I was told I can swim with the watch but can't dive deeper than 33 feet. I was also told NOT to use the watch in a hot tub because steam can still get in.

I would like to learn how to read the results to make sure what I was told is correct. Can anyone help?

[marblegranite]

Wow, no one knows how to read these results here either? No wonder the repair guy seemed confused and unsure when he told me I was okay up to 33 feet.

[surrealmethod]

a negative bar is done in a vacuum. So those test will be used in high altitude situations. They're also important when graphing the values... but in your situation, they're not necessary.

As far as the positive bar, it shows depth in water. The relation of 1 bar to 33 feet is somewhat true but bar is a unit of pressure while feet is in length. 1 bar is the unit of pressure at sea level. If you go down another bar you will descend 33 feet.

Your watch failed the 10 bar test. It held the 2 bar test but had 74 um of deformation. Unfortunately, every watch is different and depending on the gaskets and construction material, this could matter... but the watch did hold 2 bars of pressure thus why they mentioned you could go down 33 feet.

Test 3 (the +1 bar) should have been done first to relate sea level... but it doesn't really matter.

[surrealmethod]

I should also carify that I speak of the topic from my experiences in the engineering world.

I have never had a watch tested or have used one of these machines myself so my understandings could be way off and hopefully someone can chime in.

[marblegranite]

In case anyone else is trying to understand their own test results, here is the feedback I received on another forum:

The bottom line is these are air tests and until the watch goes through a more comprehensive water test there is no way to guarantee that it is waterproof.

P1 is a standard water resistance test for non-diver watches.

P6 is a 100m divers watch test.

P5 is a jewelry watch test for watches with less stable cases....

So looking at the three tests I would agree it passed the general water resistance test (although with a lot of deformation), failed the diver watch test in vacuum but passed in pressure mode, and passed the jewelry watch test. Looking at the results I would say it's safe to use it for hand washing and surface swimming, and would not trust it for anything else. It MIGHT take a dive to the bottom of the swimming pool.

Note these are air tests and not water tests. I used to dive professionally and I always had repaired dive watches first air tested, then when passed I had them water tested - that's the only way to be sure.

School of hard knocks: I once had a 600m Seiko tuna can pass the air test but flooded when I used it diving....ever since that happened I have them water tested if I'm going to use them for diving.

[panerai153]

I pretty much agree with your quote information. Unfortunately, most of the watch manufacturers use the air test to determine water resistance.First off it's faster, especially if you are going to test for depths like 100-200 Atmos.It takes an expensive hunk of a chamber to water test for real depth. The average hand pumped tester is only good for 3-10 bar, which isn't enough for divers. The second reason, if a watch has a catastrophic failure while air testing,there aren't going to be any water flood problems, which are a possibility with water testing. I do agree, if I were using a watch to dive, I would want it water tested before using it at depth. If it floods at 90 feet in salt water, pretty much what you have is a paperweight on a bracelet. Better to be safe than sorry.

[Jkay]

From a layman's perspective, water is quite a bit more dense than air. Quite a bit.

So why would you say that an air leak test is not as sufficient as a water test?

From an uneducated point of view, how can dense water leak in where imperceptibly ethereal air can not?

[Jkay]

Also, why is a 330ft dive rating not be "good enough" for divers?

I guess I have to be a diver to understand.

[DeeKa]

Also, why is a 330ft dive rating not be "good enough" for divers?

I guess I have to be a diver to understand.

It's according to industry standards.

200 m / 660 ft is the tested pressure to be passed for a watch suitable for "diving". And remember, not every diver just goes down to 20 m. I know some "normal" recreational divers reaching 100 m, well I'm keeping myself at 60

Dee

[Jkay]

It's according to industry standards.

Thank you for explaining.