The rubber coat of these pot magnets protects the sensitive surface from scratches and increases the load capacity in shear direction. We also carry pot magnets with internal thread without rubber coating.
Principle: The strong neodymium magnets are 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. In order to move the magnet sideways, it doesn't take as much force, despite the rubber coating. Therefore, you can strain a pot magnet much less if you use it on a wall as opposed to using it on the ceiling.
Rust: The rubber protects the magnet from occasional wetness or splash water. Permanent outdoor use, however, may lead to rust build-up. Guaranteed rust-free, on the other hand, are our ferrite pot magnets as well as our waterproof magnets.
All further information regarding these products can be found in our FAQ about pot magnets.