Demagnetizing without demagnetizer

1. ## Demagnetizing without demagnetizer

Are there any ways to demagnetize a watch without a demagnetizer or am I pretty much locked into picking up an electronic version

2. ## Re: Demagnetizing without demagnetizer

You need to get your watch exposed to an irregular magnetic field. Then the magnetic moments in the steel parts will become irregular, and thus be demagnetized.

3. ## Re: Demagnetizing without demagnetizer

Originally Posted by thedeandk
You need to get your watch exposed to an irregular magnetic field. Then the magnetic moments in the steel parts will become irregular, and thus be demagnetized.
Are you talking alternating polarity? Because that is what I was thinking of trying. I have several magnets I was thinking of laying out in alternating polarities and sliding a watch across them in an attempt to peel the magnetic field out of the watch.

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5. ## Re: Demagnetizing without demagnetizer

Originally Posted by OnlyOneMore
Are you talking alternating polarity? Because that is what I was thinking of trying. I have several magnets I was thinking of laying out in alternating polarities and sliding a watch across them in an attempt to peel the magnetic field out of the watch.
I'm too sure about that. I'm no expert, and I encourage you too try. But just thinking about your method, seems like you would just increase the watches magnetism each time

These tools exist for a reason. I'm not sure what you are trying to accomplish here

6. ## Re: Demagnetizing without demagnetizer

One item that amazed me is a permanent magnet magnitizer/de-magnetizer sold in machinists supply catalogs. It's basically a block of magnet material with a rectangular hole and a stepped hole. You can pass a screwdriver through the rectangular hole and pick screws up with it, then pass it through the stepped hole and viola, screws no longer stick. It isn't sized for a watch though, although you could use it on parts.

I suppose this demagnetizer works by a varying magnetic field, but it certainly isn't alternating. After taking Physics 51 (E&M for Engineers) in college, a fellow machinist showed me one and I thought "There's no way this thing is gonna work". But it did.

You just gave me an idea, how about the pole pieces for a shaded pole fan motor. Any cheap fan has one, just take the motor bearings off and remove the rotor. It would probably overheat due to the missing reluctance of the rotor, but use a Variac to turn down the input voltage until it doesn't overheat. Then put the watch where the rotor was and slowly pull it out.

On second hand, I have one of the cheap blue ones on order from China, think I paid \$11 for it.

7. ## Re: Demagnetizing without demagnetizer

I read the little blue ones aren't powerful enough to work on a cased watch and I'm too cheap to buy a more powerful unit for the once/maybe twice I'm probably going to use it. I just wondered if there was a way to repurpose some of the magnets I have laying around

8. I managed to demagnetize one of my watches the other day using a bar magnet. I found the magnet was slightly concave on one side and convex on the other—just enough that I could “spin” it on my desk and have it turn for two or three seconds. While it was spinning, I passed the watch over the magnet, then checked the watch with a compass. It worked! Watch no longer deflects the compass needle. Suddenly, instead of gaining 30 or 40 spd, the watch is +3/-2 spd depending on position.

It took a little trial and error, but if you can get the magnet spinning it works great. If I hadn’t been able to spin it on my desk, my next step would have been to tape it to a drill or a dremal. Note, the orientation of the magnet matters. Spinning a coin shaped magnet—with plus on one face and minus on the other—probably wouldn’t have worked. But a bar magnet did great.

9. ## Re: Demagnetizing without demagnetizer

Originally Posted by jwillson
I managed to demagnetize one of my watches the other day using a bar magnet. I found the magnet was slightly concave on one side and convex on the other—just enough that I could “spin” it on my desk and have it turn for two or three seconds. While it was spinning, I passed the watch over the magnet, then checked the watch with a compass. It worked! Watch no longer deflects the compass needle. Suddenly, instead of gaining 30 or 40 spd, the watch is +3/-2 spd depending on position.

It took a little trial and error, but if you can get the magnet spinning it works great. If I hadn’t been able to spin it on my desk, my next step would have been to tape it to a drill or a dremal. Note, the orientation of the magnet matters. Spinning a coin shaped magnet—with plus on one face and minus on the other—probably wouldn’t have worked. But a bar magnet did great.
Now that's being creative.

Another way of demagnitising steel without using a demagnitiser is to hit it with a hammer a few times.............

10. ## Re: Demagnetizing without demagnetizer

Originally Posted by jwillson
I managed to demagnetize one of my watches the other day using a bar magnet.

It took a little trial and error, but if you can get the magnet spinning it works great.
Just out of curiosity, did you notice eddy current damping when you got the watch near the magnet? The magnet would have slowed much faster than without the watch present. Not to question the effectiveness of your trick, but I think either the case/movement doesn't conduct electricity very well, or the magnet would have stopped pretty quickly. I know stainless isn't a great conductor, and whatever alloys they use for plates are probably more highly alloyed and even worse conductors.

The conductivity doesn't affect demagnetising, but a stopped or slowly turning magnet would.

11. ## Re: Demagnetizing without demagnetizer

Originally Posted by OnlyOneMore
Are there any ways to demagnetize a watch without a demagnetizer or am I pretty much locked into picking up an electronic version
you can literally buy a demagnetizer on ebay for \$12. Is it worth it to go crazy trying to figure the physics behind demagnetizing to save 12 bucks?

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