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FAQ - Frequently Asked Questions

What are special features of a pot magnet?

Table of Contents:

Important features of pot magnets

Key points: When handling pot magnets, keep the following in mind:

Principle:

A pot magnet is embedded in a steel pot. The steel pot increases the adhesive force of the magnet on direct contact with a thick iron surface. If there is no direct contact with the counterpart, or if the steel plate is thin, painted or rough, you can strain it much less.

Shear force:

The indicated adhesive force was measured perpendicular to the surface to which the magnet should stick. It takes a lot less strength to move the magnet sideways. Therefore, you can strain a pot magnet much less if you use it on a wall as opposed to using it on the ceiling. Please note our FAQ regarding shear force. By using appropriate rubber caps on the bottom side of pot magnets, you can enhance the adhesive force in shear force considerably. Or you can use pot magnets with rubber coating: They adhere much more in shear force.

Rust:

Neodymium pot magnets are not rust-proof and therefore intended for dry indoor use. Our ferrite pot magnets, on the other hand, are rust-proof.

Maximum working temperature:

Most pot magnets can be heated to a temperature of up to 80░C without losing their magnetisation (ferrite magnets and certain CSN-types even higher). The adhesive that connects the magnet and the steel pot may become brittle at continuous heating to this temperature. Hence, it is recommended to use pot magnets only at room temperature.

Magnetic flux lines of raw magnets vs. pot magnets

Disc magnet in free space

Raw magnet

With a "naked" magnet (raw magnet) the field lines move freely through the air. They surround the magnet widely in all directions and can therefore attract a counterpart from a distance of a few millimetres.
Disc magnet on iron contact surface
Pot magnet in free space

Pot magnet

The field lines move even easier through iron than through the air. The steel pot of a pot magnet directs the magnetic field lines downward to the contact surface. This causes the magnetic force to be bundled at the contact surface (see picture below).
Pot magnet on iron contact surface
Adhesion diagram of article CSN-16
Such a strong adhesive force occurs only on direct contact with the counterpart. A pot magnet is not suitable for attracting an iron subject over a distance of several millimetres, since the field lines don't cover this distance.
Example adhesion diagram of article CSN-16 (max. adhesive force: 4 kg): At a distance of 1 mm between pot magnet and steel plate, the max. adhesive force is still 1 kg, at a distance of 4 mm and more there is no more adhesive force left.

Why can't I put two pot magnets flush on top of each other>

Unfortunately it is true: You can't stack two pot magnets exactly on top of each other, because this way they repel each other. Pot magnets can only be arranged side by side and staggered (see picture and video).
The reason is that all our pot magnets have the same pole on the adhesive surface, e.g. always the north pole (coloured in red). The steel pot is the south pole of this system (coloured in green). If two pot magnets are near each other, the north pole of the one pot magnet attracts the south pole (=steel pot) of the other. Hence, the pot magnets arrange themselves next to each other. It is not possible to put them on top of each other, because the same poles repel each other.

Offset

To protect the magnet and ensure maximum adhesive force, the magnet must not protrude from the pot. In practice the magnet is lightly recessed in the pot, which varies from magnet to magnet, but the adhesive force indicated on the web shop is guaranteed.

Suitable counterparts to pot magnets

Screw-on metal discs

As ideal surface for pot magnets we recommend affordable and practical countersunk metal discs. They can easily be screwed onto non-magnetic surfaces with a countersunk head screw. They are also suitable counterparts for disc magnets (available with our without borehole).
Select a counterpart that is slightly larger than the diameter of the pot magnet, which ensures that the magnet has some leeway on the disc and still unfolds its full adhesive force.
Go to screw-on metal discs

Glue-on metal discs

We also recommend self-adhesive metal discs as counterparts to pot magnets (available untreated or with white coating). They are only suitable for pot magnets and disc magnets with a diameter of up to 20 mm.
Go to glue-on metal discs

Combination of pot magnet with raw magnet

Normally you place a pot magnet on an iron counterpart. This results in a very high adhesive force (see explanation above).
If you combine a pot magnet with a raw magnet, however, the magnetic flux lines are not bundled downwards but distributed in a large area. The adhesive force is only a fraction of the indicated maximum adhesive force. If you want to combine pot and raw magnets, you have to use magnets with a significantly higher adhesive force.
Pot magnets on iron
Pot magnet on raw magnet

Pot magnet application areas

Pot magnets are especially suitable for use in the following industries:
  • Booth construction, store construction, interior fittings
  • Bath and kitchen installations
  • Cabinetry, furniture construction
  • Metal construction
  • Machine and plant construction
  • Lighting industry
But pot magnets are also a good solution for hobby and leisure use, which is illustrated in the following customer applications: