The Right Way to Demagnetize Your Watch Movement at Home

NH movements normally run at -20 / +40 seconds per day which is quite good for its caliber. This can be improved even further with regulation which you can learn more about here. So what does it mean when you notice that suddenly, your watch is running a few minutes past per day when you haven’t dropped or dinged it anywhere hard enough to cause this level of inaccuracy?

In most cases, when a Seiko suddenly goes haywire like this, you're looking at magnetization. But good news! This is one of the easier problems to fix with watches, although it does require special tools that you most likely don’t have at home yet unless you’ve been practicing watchmaking for a while. Read on to know how you can safely demagnetize your watch at home.

 

What Magnetization Actually Does to Your Movement

To put it simply: your movement has a hairspring that controls timing. When that spring gets magnetized, the coils stick together, and stuck coils mean a shorter effective spring length. Shorter spring means faster oscillation, which in turn means your watch runs faster than intended. That’s the whole problem!

Source: Pocket Watch Database

 

This issue has been affecting mechanical watches for a long time, making these timepieces unreliable for certain professionals that routinely deal with magnetic apparatus. That’s why some watch brands have models that are purpose-built to withstand strong magnetism like the Rolex Milgauss or the Omega Seamaster Aqua Terra.

In our modern age, magnetic fields are much more common. Your phone has them. Your laptop has them. Even some watch straps use magnetic clasps that can mess with your movement over long periods of time. You don't need to work in a power plant to magnetize a watch these days - just set it on top of your iPad overnight and you might wake up to a problem.

 

Test Before You Touch Anything

Source: World Tempus

 

Don't assume you know what's wrong. Test it. Grab any compass; the cheap plastic ones work fine, or use an old-school metal one if you've got it. You can even McGyver it and float a needle on a bowl of water. You can even get a compass app on your phone, although some older models may not have magnetic field sensors built in.

Put the compass on a flat surface and let it settle. The needle should point north and stay there. Now bring your watch close, about an inch away. Move it around the compass slowly. If your watch is magnetized, that needle will follow it around like it's on a string. If your watch is fine, the needle might wiggle slightly but won't swing hard toward the watch.

This test takes less than a minute and saves you from wasting time on the wrong fix. 

 

The Tool You Need: A Demagnetizer

Source: Hodinkee

 

A demagnetizer is a simple device that creates an alternating magnetic field. When you move a magnetized object through this field correctly, you neutralize the magnetic charge. These things run from about $15 for basic models up to $50 for slightly nicer ones. The expensive ones might look cooler on your workspace or last longer in a commercial shop, but they don't actually demagnetize any better. If you just want to DIY it for the experience, cheap demagnetizers are fine.

There are two common designs. Some have a flat surface where you place the watch. Others have a circular coil you pass the watch through. Both work the same way. Pick whichever one looks easier to handle.

Buy one, stick it in your toolbox, and you're set. 

 

How to Demagnetize the Right Way

Clear your workspace first. Move other watches, metal tools, and anything magnetic at least a few feet away. You're about to create a magnetic field, and you don't want to magnetize something else while fixing your watch.

If you’re using the flat demagnetizer tool, place the watch face up on the tool, hold down the power button, then slowly lift the watch away from the tool over 5 seconds. If you’re using the coil type tool, the steps are similar: turn on the power button and pass your watch through the hole 1 or 2 times slowly, like someone getting an MRI scan. 

Source: Vintage Watch Inc.

 

Now here's the part that matters most: pull the watch away from the demagnetizer in one slow, continuous motion. Don't jerk it. Don't pull it away quickly. Slow and smooth. 

Why so slow? Because the demagnetizer creates a magnetic field that alternates polarity rapidly. As you move the watch away, the strength of that field decreases gradually. This gradual decrease is what actually removes the magnetism. Your watch gets hit with weaker and weaker alternating magnetic fields until there's essentially nothing left.

Pull away too fast and you cut the process short. The watch might still hold some magnetism. 

After one pass, test with the compass again. The needle should stay still now. If it still moves toward your watch, you've got residual magnetism, in which case you just repeat the process.

 

Wrap Up

Prevention is easier than fixing, so develop these basic habits and you won't have to demagnetize your watch as often, if ever. Stop putting your watch on top of electronics. Get a watch box or designate a spot on your dresser that's away from phones, laptops, and tablets. When you're modding, think about what's magnetic and what's near your watch.

Ready to try your hand at modding and facing the hurdles that you might encounter along the way? Go check out our huge catalog of Seiko mod parts for SKX, SRPD, and other watch models that are guaranteed to look awesome! We have individual parts and even all-in-one watchmaking kits to suit any experience level.

Happy modding!