Some photos of the pressure testing process

I've seen a few threads where people are asking about pressure testing issues, so I thought I would show what I do in my shop to help people understand the process.

If you are using an independent shop to service your watch you need to ask your watchmaker what sort of pressure testing equipment he/she has. Not everyone has the equipment needed to test to higher pressures.

In my shop I have two pressure testing machines. One is a dry tester and uses a compressor to check the watch with both vacuum and pressure. The machine measures the deflection in the case to determine if the watch is water resistant. It has many programs for different types of watches (and I can create custom programs as well), but the limits of it's capability are -0.7 Bar, and +10 Bar. Here is the machine after a test of a JLC Master Compressor Memovox, showing that the watch passed on both the vacuum and pressure tests:



For watches that are rated in excess of 100 meters (10 Bar) I use a wet testing machine capable of 125 Bar or 1250 meters. All watches are first tested in the dry tester, and the final pressure test is done in a testing chamber filled with water.

Here a Doxa I serviced is placed in the chamber and the chamber is filled with water:



The unit is sealed and the test is ready to begin:



The pressure inside the unit is raised by turning the knob on the right side, while reading the gauge on the left. The pressure used is typically slightly above the rated pressure of the watch. In this case the watch is rated to 600m or 60 Bar, and I have the pressure set to 70 Bar (approx. 1,000 pounds per square inch):



After a defined period where the watch is left at pressure, the watch is removed, dried off, and placed on a heating unit that is tuned to a specific temperature. The watch is left there again for a defined period of time, then a drop of room temperature water is placed on the crystal:



The drop is cleaned away and the crystal is checked (using a loupe) for any condensation. If condensation is present, the watch has leaked. If there is none, as in this case, the watch has passed the pressure test:



Not all water testing equipment is of the same brand obviously, so the equipment shown is only one option available to professional watchmakers.

If you do expose your watch to water on a regular basis, I recommend getting the watch pressure tested at least once per year. The testing is a small cost in comparison to the work required when water does enter the case, as in this Tag I am working on now. You can see the dial and hands have been damaged by water intrusion into the case:



And there are small spots of rust on the movement in various areas:



The stem is rusted badly and will be replaced, as well as several other movement parts that were affected by the water:



Here the case has failed the pressure test, and I had to replace the case back gasket, crown, and case tube. The case still failed the testing and I found the plastic gasket for the crystal had a crack in it and this was another area for leakage:



The watch won't leave my shop until I know it meets the standards set out by the manufacturer.

I hope this helps you understand the process better. If anyone has questions about this please let me know.

Cheers, Al