How to remove the "donut" magnet from an audio speaker

First publication: August 21st, 1999
Last update: October 10th, 1999

This WEB page is not a message from David Hamel - but something that can help you. To remove the "donut" shape ceramic magnet from an audio speaker is easy and safe. You can do it yourself at a very low cost.

Method 1 - by Etienne Lahos (21-8-99)

This method described here was found by my good friend Etienne Lahos. He tried many things before this simple procedure. There is no risk to break the magnet if you follow the instructions. I tested his method myself and it works all the time, with a small speaker (1" outer diameter) to very big "woofer" (12" outer diameter donut magnet...).

Here are the tools you need:

- Of course, an audio speaker (or a big audio "woofer") that uses a "donut" shape magnet. Take note that most recent audio speakers use this kind of magnets, but older ones use cylindrical metal magnets (discard these speakers because you don't need them here). For a first trial, I suggest you to practice with a small audio speaker with a small magnet.
- A flat screwdriver
- A bench vice
- A propane torch welder
That's all !!

There is a round metal plate on each side of the "donut" magnet. Both of them are sticked to the magnet itself with glue. The main idea is to heat each metal plate, one at a time, as fast as you can without heating the ceramic donut magnet. By doing this, the glue on the surface of the metal plate will pass from "solid" to "near liquid". At this moment, it becomes very easy to remove them.

Here's the procedure:

To help you, see figure 1 above.

1- First, squeeze the metal cone of the speaker, into the bench vice. Don't worry, you can scrap the metal cone within the bench vice. You don't need this part. The bench vice is only used to hold the audio speaker and to work around it.

2- With the flat screwdriver, tear the whole cardboard cone inside the speaker. Remove it completely. Do the same thing with the corrugated spiral cardboard located at the bottom of the conical cardboard you have removed. The goal here is to have access to the inner ring metal plate sticked to the magnet. You will find also a small coil of wires - you can remove it.

3- Fire on the torch welder.

4- Begin with the outer metal plate (the other side of the metal cone squeezed into the bench vice). Heat it uniformly with the torch welder. You must do this quickly without heating the ceramic magnet. More you have a concentrated flame, more it's fast and less the ceramic magnet will be heated.

While heating the metal plate, after a time, apply a SMALL twist force just at the edge between the magnet and the metal plate (see figure 1) JUST VERIFY if the glue has lost its adherence. You will know that when the metal plate will move sideways a little bit.

5- At this moment only, you can turn off your propane torch welder. Then use your screwdriver to separate the metal plate from the magnet. The force you must apply is ONLY to overcome the magnetic attraction between these both parts. Important: the screwdriver is not used to break the glue - otherwise, you will break the ceramic magnet.

It's easy, heat the metal and wait until the glue has lost its adherence. Once done, use your screwdriver to simply remove the metal plate. Be cautious, it will be hot - however, the ceramic magnet is not supposed to be hot and you can handle it with your hand.

6- Repeat steps 3 to 5 for the inner metal plate on the other side of the magnet (the one connected to the metal cone squeezed into the bench vice). Point the flame of the propane torch welder toward the metal ring, at the bottom of the "cardboard" you have removed. It's the same process as the other metal plate you have just removed. When the glue has lost its adherence, remove the magnet. Be cautious because the magnet may fall down.

7- That's all! The "donut" shape ceramic magnet is now free. You can throw away all other parts of the audio speaker (or "woofer").

8- You can, if you want, remove the hard glue on each side of the magnet, by scratching it with the screwdriver or with a knife. If you want a "near perfect" surface, you can sand each side of the magnet.

9- Wash the magnet with a brush, water and soap.

The time required for the glue to lose its adherence depends on the size of the metal plate. For a small one, 1" diameter, it takes about 10 seconds. For a 4" diameter, it takes about 30 seconds. For a 12" diameter, it took me 6 minutes for each "big" metal plate.

This method works all the time with any audio speakers (or "woofers"), without any risk to break the donut ceramic magnet!!!

Special thanks to my friend Etienne Lahos who found this process and I wish you good luck!

Louis :)))

Method 2 - by Tracy Jones (19-9-99)

Tracy sent me his own procedure to do this work. Here are in his own words about his method:

My own experience with prying loose these magnets was to take a sharp heavy butcher knife and place the knife's edge between the iron attachment and the magnet. With a sharp blow using a hammer on the knife, it usually comes right off. I've separated more than 300 magnets of all sizes using this method and only broke 5.

The section towards the tip of the knife should be used. The knife needs to be very sharp and thin only at the blade edge. The edge needs to be placed exactly where the crack appears. The knife needs to be one of the old hickory type and not a serrated type. I just removed 500 from my hfs ("Hamel Flying Saucer") using this method from .010 aluminum that had been glued on. No cuts in the aluminum nor any breakage's. On radio speakers, it has always worked just fine except when I didn't place the knife's edge at the crack, but more on the magnet. Also, it doesn't require much of a blow with the hammer. Tracy.

If you do not want to do the work of removing the "donut" magnet from an audio speaker, here are 2 sources where you can buy ceramic magnets: "The Cutting Edge Company" and "Jobmaster Magnets Canada Inc.".

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