Can A Watch Become Magnetized? Causes And Fixes
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Yes—a watch can become magnetized when exposed to strong magnetic fields such as airport security equipment or MRI machines, which can turn steel screws, pinions, and the hairspring into magnets. The usual symptom is fast running of up to 60 seconds per day, and there is no permanent damage.
What Magnetism Does Inside A Mechanical Watch
At the center of mechanical timekeeping is the hairspring, a fine spring that controls the balance wheel and helps the watch keep time. That hairspring is affected by magnetism. When it becomes magnetized, its coils can start sticking together, which makes the balance wheel move faster than it should. Another way to picture the problem is through the balance spring: magnetization makes it stick together at certain points, shortening its effective length. A shorter effective spring causes the balance to oscillate more quickly, so the watch runs fast.
In some cases the watch can run up to 20 minutes off. A magnetized watch may also show an amplitude deviation, meaning the balance wheel does not swing as far as it should. That reduced swing is another clue that the regulating organ is not behaving normally. To see how these parts normally interact, the balance wheel and hairspring are worth understanding as a pair. The hairspring is not just a spring in the everyday sense; it is a timing element. Its breathing motion sets the rhythm for the balance wheel, and the balance wheel’s swing is what the movement counts. Once magnetism changes the hairspring’s shape or spacing, the rhythm changes with it. The result is usually a rate that drifts fast, not a watch that suddenly feels different on the wrist.
A watch can gain time quietly, hour after hour, until the error becomes obvious. The balance wheel may still swing, and the watch may still run, but the rate is wrong. That is why a magnetized watch can be described as gaining rather than broken. The movement is doing what it was told; the hairspring is simply giving it the wrong instructions.
How A Watch Picks Up Magnetism
Strong fields are the obvious culprit, but everyday objects deserve attention too. Phones, laptops, speakers, and handbags with magnetic clasps are common sources that can affect watches. Smartphones, computers, refrigerators, and microwaves are also on the list. A watch does not need to be inside an MRI room to encounter magnetic fields; these smaller sources are part of daily life. If you want to reduce those encounters, keeping a watch away from everyday magnetic fields is mostly about awareness.
The goal is not to fear every speaker or clasp, but to recognize that steel components can hold a magnetic charge once they are exposed. A laptop speaker or a bag clasp may seem harmless, yet the field is there. A phone resting against a watch overnight, a fridge door, or a microwave in the kitchen all belong to the same category: ordinary objects with magnetic fields. The practical point is that these fields are present in ordinary places, so magnetism is not only a laboratory problem.
Demagnetization: The Usual Fix
The fix for a magnetized watch is demagnetization. A demagnetizer reorganizes electrons in metal components to restore them to a non-magnetic state. In practice, you place the watch on top, press a button, and move the watch slowly away. If you own a watch demagnetizer, the procedure is to place the watch on it, press the button, repeat if needed, and then check accuracy.
That sequence is simple, but the underlying idea is not mysterious: the tool changes the magnetic state of the movement’s metal parts. It does not polish, oil, or rebuild anything. For a broader look at how movements are built and serviced, see manual, automatic, or quartz movements. Demagnetization targets the cause rather than the symptom. A demagnetizer can be small enough to keep at home, but it is not the only route. The procedure is repeatable, and checking accuracy afterward is the feedback loop.
Shields, Materials, And Prevention
Some watch designs include a magnetic shield placed underneath the watch case back to block magnetic fields from reaching the movement. That approach is preventive: it keeps the field away before the hairspring can be affected. A magnetic shield is a physical barrier, not software or a setting. It sits under the case back, hidden from view, and its job is to intercept fields before they reach the movement.
Materials matter as well. Traditional metal hairsprings are susceptible to magnetism, but they can be repaired or modified by hand. That is a meaningful advantage for watchmakers who need to adjust a movement rather than replace an assembly. Movement type changes the context, so if you are comparing architectures, Automatic Vs Quartz: The Real Difference is a useful next read. And if magnetism resistance is part of a larger purchase decision, it can sit alongside the questions in How To Choose Your First Luxury Watch.
A shield is not a universal feature, and not every watch is built the same way. Knowing what is inside the case—and what materials the regulating organ uses—helps you set expectations. If you work around magnetic equipment, that hidden layer can make a difference. If you do not, knowing it exists still helps you compare specifications.
A Note On Watch Games
If you enjoy turning watch details into a challenge, Watchdle offers a game-like way to test your instincts. It is a light break from the technical side of magnetism, and it fits the same curiosity that makes people wonder why a watch suddenly gains time.
FAQ
Can a magnetized watch stop running?
Yes. In an extreme case, the hairspring may stick to itself, and that can cause the watch to stop running. This is different from the usual fast-running symptom, but it shows how much the hairspring’s behavior matters.
Do silicon hairsprings solve the magnetism problem?
A silicon hairspring is completely unaffected by magnetism, so it removes that specific vulnerability. There is a trade-off: silicon watch parts cannot be manipulated or repaired once manufactured, and they must be discarded if defective.
How can I check a watch for magnetism at home?
You can use an app such as LEPSI for iPhone or Physics Toolbox Magnetometer for Android, use a compass, or simply watch the time for fast gain. Those methods can help you decide whether demagnetization is the next step.
Is demagnetization expensive?
Many watchmakers offer demagnetization for free or for a small fee. That makes it one of the simpler fixes to try when a watch starts gaining time.
