Episode V – Water Resistance
Water resistancy can be grouped under two standards: ISO 2280 and ISO 6425. Most watches, if they are not a serious real diver, will not be tested and badged under ISO 2280 standards. The real water resistance can be provided if ISO 6425 standards are applied. EG: Water resistant 20 atm is different than “diver’s 20 atm”. First one is for snorkelling, the second is for scuba diving.
There is no “water proof” watch in the world. After some time or pressure, all watches have leakage. Underwater pressure is as 1 atm increase per 10 m depth. Enormous pressure is exposed on a watch at depth, this is usually measured in centimeter squared.
There are 3 weak points on watches when water resistancy is issue:
1)Crystal gasket (I ring, we mentioned at episode 4)
The domed thick crystals always have more resistance for depth pressure due their convex structure.
The thickness of the I ring is also important.
Applied locks and under crystal secondary gaskets always pays off.
The crowns have double or triple nitrile or vitron gasket “o rings”. They are quite resistant if not exposed to direct sun light. They can last more than 10 years.
HINT: If you are looking for a sport watch, field watch or diver watch, the crown must be of a “screw down” type. There’s no difference if it’s inner threaded or outer threaded, but inner threaded ones stay cleaner and the thread is not easily stripped out.
Backlids both screw or bolted, if they have proper vitron or nitrile ring gaskets, provide water resistancy. The screw downs are a bit risky, friction during screwing down the backlid may damage the gasket. It will be better to replace backlid gaskets after opening and closing it a few times. The gaskets are very cheap.
There is no need for water resistance over 5 atm for dress or pilot style watches, but they must be min 5 atm. For me, a watch must be 5 atm water resistant at least for every type or style.
You will see Helium escape valve on cases of 300m (30atm) and over divers watches. This is for saturation. When you come up to surface the pressure inside may pop up the crystal. This valve lets out the pressure. They may be manual too, as in Omega Seamaster PO at the 10 o’clock position.
HINT: Always wash your watch under fresh water after salty water contact. Never leave your watch within salty water. This may damage gaskets.
There is certain amount of athmospheric water particles in watches. This may cause fog on the crystal. It is normal, but you may get it dried when it’s serviced.
If you use your watch differently than the designated and marked water resistance standards eg: Using a 5 atm watch whilst diving, there will be leakage. The fog may appear ( if you are lucky, the watch will survive, and it will not fill with water)
The appearance of fog means there is a slight amount of damp air in the watch. I know, it looks nasty and irritating. It occurs when the crystal is cold and backlid is warm. It is kind a condensation on the surface.
Today there are lots of desk divers. People like them, buy them, wear them. Actually most don’t comply with ISO 6425. They’ve never really been tested. Never actually left under designated pressures. Most testing is simulated in the factory with a pressure testing device, that actually doesn’t involve water. Basically the pressure is changed in the chamber to the amount required (20atm for example) and it then senses if this drops. If it does, it means that some of the air has leaked into the watch. If it doesn’t, it means the watch can handle that pressure with air and since water is thicker than air, water therefore won’t leak in either. Some check for deformations at different pressures by being in contact with the crystal during the test. Most don’t test to more than 1.5atm pressure in reality…
HINT: While choosing a diver watch, and if you would like to know if it will survive the indicated water pressures, be sure there is an indication of compatibility at their website, user manual etc. It will be better to search and buy a REAL ISO divers watch. I can not name a brand here, but there are really cool macro and micro brands that are actually meeting standards.
The rotating ring is not a must nowadays with it’s indications in 15 min increments. These bezels are made of ceramic mostly and look nice. It is a quick time keeper for divers both ascending and descending, to check air left at tanks etc. Be sure it is unidirectional and clean neat clicks 60,45 or 90 ….
For all movement type wrist watches there are 3 deadly enemies :
Many watches are broken down and serviced because of water leakage. Have you ever taken hot a hot shower with 3 atm water resistance watch left on your wrist? Probably it ended with disaster, or luckily nothing happened.
In reality, hot water causes metal and gaskets to expand and therefore compromises them. You should never really wear ANY watch in the bath or shower.
From many years ago, the voice of a 70 year old watch repairer of my youth, echos in my ears: “Nobody gets in water with a watch they love”
Nowadays there are diving computers, designed for the job and better suited. If it makes you happy, you may prefer to dive with your diver watch, as secondary time keeper. It is truth that, we mostly wear divers at pools and beach. Heck, most never dive in their watches, but it’s nice to know that they’ll survive washing the car at the weekend.
Here are some serious divers: