How to demagnetize a magnet

Due to frequent use, or perhaps an accident, it is possible for a magnet to lose some of its magnetic force or stop working altogether. Also, it can be useful to know different methods to demagnetize a magnet. There are various tools or pieces of equipment that need to be demagnetized for various reasons. Some engine parts, industrial tools, kitchen materials, parts that have been welded and parts that are going to be used as metal molds.

In this article you will discover how a magnet can be stripped of its power of attraction and used for another purpose. There are different home methods that can be used, and each can be useful depending on the resources available.

How do I magnetize a magnet?

Here are some of the most commonly suggested methods to try at home:

The double tap method.

This is an effective and relatively fast method that can be used frequently to magnetize.

• Place the steel bar that you are going to magnetize on two magnets that are also shaped like a rectangular bar. Both magnets should be on opposite sides of the steel bar, and each should touch an opposite pole to its corresponding side of the steel bar.
• The next thing you should do is get two more magnets (also in the form of a bar); make sure they are strong.
• Take each magnet by one end forming an angle of 45º with respect to the bar and touch the opposite end to the center of the bar. Each point of the new magnets should correspond to the same pole of the magnets below.
• Now rub each pole of the new magnets towards the bottom magnets and move the magnets up when the friction reaches the end of the bar. Repeat this process from the center of the metal bar several times.
• Each side of the bar you are magnetizing will have an opposite polarity to the magnet you are rubbing on that side. You can mark the resulting polarity with ink for future reference.
• When you have repeated this process several times you can test the magnetism of the bar by using small metal objects to test its attraction. We suggest tacks or office clips.

And then how to remove magnetism from a magnet?

There are several methods, and some of them may work only partially:

Using brute force

Hitting with a hammer, dropping or subjecting to constant small blows, such as leaving it inside the uncovered trunk of a moving vehicle.

heat the magnet

A magnet can lose its magnetism if it is heated to a certain temperature, called the Curie point. In iron it is 770 degrees Celsius, in steel it is 880 degrees Celsius, in Nickel it is 358 degrees Celsius, cobalt has the highest Curie point of all these with 1,121 degrees Celsius.

You can use lab tongs to grasp one side of your magnet and a lab burner to heat it directly with fire.

induction method

If two magnets are placed side by side with like poles together, each magnet will induce an opposite polarity in the other. As a result, each magnet will lose magnetism on its part.

electricity method

If you surround the coiled magnet with copper wire and connect each end of the wire to an AC regulator, you will be able to demagnetize your magnet. You will need to periodically reduce the current to zero. The magnet will lose its magnetism, since the alternating current constantly changes direction.

References

FicaeTV. (2012). Demagnetization of a magnet using temperature. Available at: https://youtu.be/3PgXpezpfbQ

Immagnets (s/f). How can you demagnetize a magnet? Available at: https://www.imamagnets.com/blog/como-se-puede-desmagnetizar-un-iman/