# How do I remagnetise a magnet? **URL:** \ **Category:** Factual Questions\ **Created:** [January 26, 2004, 2:08pm UTC](https://boards.straightdope.com/t/how-do-i-remagnetise-a-magnet/226145 "2004-01-26T14:08:35Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Tuco](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tuco](https://boards.straightdope.com/u/Tuco)\ **Post date:** [January 26, 2004, 2:08pm UTC](https://boards.straightdope.com/t/how-do-i-remagnetise-a-magnet/226145/1 "2004-01-26T14:08:35Z")
I’m at work and I’ve been asked to remagnetise a couple of magnets, only problem is I have no idea how! They’re just normal bar magnets, nothing special, and they don’t need to be _super_ powerful, just strong enough to move iron filings, nails, etc. Thanks, Tuco. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [January 26, 2004, 2:33pm UTC](https://boards.straightdope.com/t/how-do-i-remagnetise-a-magnet/226145/2 "2004-01-26T14:33:54Z")
The very simplest method is to use a good magnet. Take the good magnet and stroke it _in one direction only_ along the length of the magnet to be remagnetized in a line with the intended poles. Repeat this several times. ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [January 26, 2004, 3:00pm UTC](https://boards.straightdope.com/t/how-do-i-remagnetise-a-magnet/226145/3 "2004-01-26T15:00:12Z")
The usual method is to put the magnet in an alternating magnetic field. This causes the field in the magnet to cycle through the entire hysteresis curve. Then the applied field is gradually reduced to zero which results in demagnetization. ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [January 26, 2004, 3:03pm UTC](https://boards.straightdope.com/t/how-do-i-remagnetise-a-magnet/226145/4 "2004-01-26T15:03:56Z")
Holy cow! It’s early in the morning and I read **re** magnetize as **de** magnetize. Follow QED’s method. As a bonus, is your **are** ever asked to **de** magnetize you now know how. We offer a complete service from A to Z whether or not it is asked for. ---
**Author:** ![spingears](https://avatars.discourse-cdn.com/v4/letter/s/ebca7d/32.png) [@spingears](https://boards.straightdope.com/u/spingears)\ **Post date:** [January 26, 2004, 3:16pm UTC](https://boards.straightdope.com/t/how-do-i-remagnetise-a-magnet/226145/5 "2004-01-26T15:16:22Z")
Using another magnet works under centain conditions. The magnet must be stronger than the finished magnet you wish to achieve. Magnets are magnetized commercially with specially wound heavy duty cable/wire. coils. The piece to be magnetized is placed inside the coil. A large amperage DC current is discharged through the coils to produce a very strong magnetic field and the job is done. You can wrap a soft iron or steel bar with as many turns of # 10 or 12 wire as possible. Connect one end of the wire to a car battery. Then apply the other end of the wire to the other battery terminal, BRIEFLY. Voila… the bar is (re)magnetized. you can repeat this two or three times to enhance the magnetic field of the bar. Wear safety glasses and/or face shield while working around batteries! ---
**Author:** ![bbeaty](https://avatars.discourse-cdn.com/v4/letter/b/c0e974/32.png) [@bbeaty](https://boards.straightdope.com/u/bbeaty)\ **Post date:** [January 26, 2004, 11:40pm UTC](https://boards.straightdope.com/t/how-do-i-remagnetise-a-magnet/226145/6 "2004-01-26T23:40:03Z")
> [@Tuco](#): > > I’m at work and I’ve been asked to remagnetise a couple of magnets, only problem is I have no idea how! They’re just normal bar magnets, nothing special, and they don’t need to be _super_ powerful, just strong enough to move iron filings, nails, etc. > > Thanks, > Tuco. Arbor sells an expensive re-magnetizer: > **[Magnetism & Magnets](https://www.arborsci.com/collections/magnetism-magnets)** > > Magnets are awesome. Browse our attractive lineup of magnetic products designed to help students appreciate and understand this invisible force around us. Model the Earth's magnetic field with the Magnetic Globe, demonstrate induced magnetic fields... Much easier: get yourself a neodymium supermagnet. Stroke it along the bar magnets a couple of times on both sides and they’ll be remagnetized. Neodymium magnets can be found for cheap at [http://www.wondermagnet.com](http://www.wondermagnet.com) ---
**Author:** ![\_xiao\_wenti](https://avatars.discourse-cdn.com/v4/letter/_/b782af/32.png) [@\_xiao\_wenti](https://boards.straightdope.com/u/_xiao_wenti)\ **Post date:** [January 27, 2004, 11:10am UTC](https://boards.straightdope.com/t/how-do-i-remagnetise-a-magnet/226145/7 "2004-01-27T11:10:53Z")
I frequently have to reset some 2-inch alnico magnets that we use to bias during deposition. Granted, I have tools not available to others. I use a 1.6 tesla electromagnet. The hard part is to keep them from slamming into the poles.