Pressure Testing Your Watch


One of the most popular watch repairs we are asked to carry out at Timepiece Watch Repairs Blackburn is a watch 'pressure' test. This is usually required after a new battery is fitted or, less commonly, when other case repairs are carried out such as a new glass, pusher or winder. Each of these components play an integral part in your wristwatch's resistancy to water. A pressure test will confirm that your watch is still water resistant to it's original depth once a repair has been carried out.

Any sealed (splash-proof or higher) watch was originally constructed with seals of various types and qualities at each entry point to the watch case. Water entry points include:

- Glass
- Case back
- Buttons/Pushers

Some watches may have other entry points however these are the most common. Over time seals on these parts can begin to wear. Whenever one of these seals is removed to gain case entry or to replace a damaged part, the seal is effectively no longer guaranteed water resistant and a pressure test will be required. A 'reseal' and pressure test can be carried out for you by Timepiece Watch Repairs Blackburn after a battery replacement or other repair for your peace of mind.

If seals are worn out, they can usually be replaced. Rubber seals, over time, will dry out and start to crack, particularly if the watch is worn in salty or chlorinated water. If the seals are good, an application of the correct greases will maintain their condition at each reseal.

Once your watch has been professionally sealed, it is time for a pressure test. This test can be carried out in a number of ways. The most common are an air test and a water test.

Air Testing
With an air test (also known as a vacuum test), your watch case is placed with it's case back on a small podium inside a machine with a fine 'needle' resting on the centre of the watch glass. Air is sucked from inside the machine creating a vacuum around your watch. Air pressure inside your watch will try to equalise with the air pressure outside the watch causing the glass of your watch to bend very (very) slightly outwards. This convex bend is then measured by the needle. Over the next minute or so, this measurement needs to be checked for changes. If the measurement has changed, then the air pressure has equalised (if only slightly) signifying a leak. If it has stayed the same then the watch is most likely air tight.

The advantages of this type of test is that it is quick and water free. The disadvantage is that watches with thick glass can sometimes fail to bend, so no variation can be observed. If your watch glass is curved then the needle can sometimes move causing an inaccurate reading. Also, no specific water pressure is defined, only that it is air/water tight to a degree.

Water Testing
Water testing involves placing your watch case in a pocket of air above water inside a tank. The air pressure inside the tank is then increased. After a minute or so, the watch is then submerged in the water and the air pressure is then released slowly. As with the air test, any air that leaked into the watch before it was submerged will now try to equalise with the lower pressure outside. If this occurs, it is clearly visible in the form of a constant stream of bubbles coming from the location of the leak. Note that air is coming out, not water going in. If this bubbling doesn't occur, then the watch is air tight. Unlike the air test, the air pressure can be adjusted to test for different underwater depths e.g. 50 metres, 10 metres etc. This kind of test takes a little longer than an air test but is much more accurate and allows a technician to locate the exact position of any leak making any necessary repairs quicker and most likely more cost effective.

At Timepiece Watch Repairs Blackburn we use water testers and our technicians can normally install a new high quality battery and pressure test your watch to the manufacturers specification within half an hour. At Timepiece Watch Repairs Blackburn we only use high quality silver oxide batteries. Poor quality silver oxide batteries can leak, possibly damaging your watch, sometimes irreparably. Alkaline batteries, whilst similar in appearance, do not usually last more than a few months and yet again there is a high risk of leakage when used in a watch. Our staff are well trained and experienced and can replace your watch battery correctly and professionally without damage to the case back, movement or battery clamp.

We also carry out many other watch repairs including servicing to most brands of watches. Please call in to your nearest Timepiece branch and speak to one of our experienced technicians for help and advice with your watch repair. We also stock a large range of quality new watches including, Casio watches, Swatch watches, Skagen watches, in store.