Crown cap magnets

Embedding magnets in crown caps
Author: Thomas Westphal, Berlin, Germany, [email protected]

Problem: Weak magnets

There is one thing I always get upset about: The magnets that come with whiteboards or magnetic boards are usually so weak that gravity takes over when you try to pin several pieces of paper together. This is especially annoying during presentations when papers start flying around.

Neodymium magnets: Yes, but...

The solution for this problem was clear: I needed stronger magnets. I quickly found what I was looking for at supermagnete.nl and ordered 20 disc magnets 10 x 10 mm. These possessed the desired holding power, but were hard to handle. Removing them from the magnetic board was difficult because the magnets were so small and hard to grasp. Also, the magnets liked to clash.
Then I had the idea of glueing the magnets into old crown caps with a strong adhesive. Even then the result was not satisfactory because the plastic coating in the crown caps prevented a permanent hold. If one fell to the floor, the magnet jumped out and the crown cap got bent. Scraping off the coating was unpractical as well.

Permanent hold

I went to the hardware store and bought a can of polyester resin and sealed the magnets in the crown caps. I used a metal mat underneath so the magnets would stick to that instead of the polyester resin can.
I used the following material:
  • Crown caps
  • Disc magnets S-10-10-N
  • a can of polyester casting resin
After the hardening, the casting resin was a little sticky and attracted all sorts of dust, but that didn't hurt its functionality.

Applications

Finally, I have magnets that look good, can easily hold 20 DIN A4 sheets and document the drinking habits of their owner. Since I have the crown cap magnets, the applications are manifold. They hold on to nails and screws or fasten the tablecloth on the garden table. However, it's best to place the magnets somewhat hidden; otherwise people might mistake the crown caps for garbage and throw them away.

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