Suggestions for Mounting
Because of their strength, neodymium magnets can be difficult to mount securely. I offer the following considerations:
- When mounting magnets, be sure to get the polarity of the magnets correct so that they attract or pull as per your wishes.
- Magnets are secure if they are mounted behind a surface. However, even a small gap between the magnet and the object being pulled can reduce the pull strength a lot.
- Magnets are secure if you use a type with a countersunk hole, with a screw or bolt. However if you use say a spade-bit to drill a hole to recess a magnet flush with a surface, then the point of the spade-bit may remove the very material that you want a screw to grip into.
- If you choose a cylindrical magnet with enough length, then secure mounting can be achieved by drilling an undersized hole in the material, say 0.1 or 0.2mm less than the magnet diameter, and force-fitting the magnet into that hole. This method does not have messy glue involved.
- Relying on adhesives alone can be unsuccessful. When a strong magnet collides to another magnet or steel, quite an impact is involved. Most adhesives, especially Superglue, eventually set sufficiently brittle that repeated impact can make them fail. Probably the most successful adhesive is a slow setting epoxy, such as Araldite Superstrength. It will be much more successful if it comes up the sides of the magnet. Clean magnet surfaces first to remove any trace of oil.
- If you want to glue a magnet into a hole, it is best to drill that hole slightly oversize so that there is room for glue up the sides of the magnet for added security. However then it is difficult to keep the magnet in its correct location until the glue sets.
- Disc magnets can be held to a surface with industrial strength adhesive tape. But personally, I would not trust it. But tape is good for attaching a magnet to the back of a thin sheet of material
- Disc magnets can be used successfully when sewn inside a cavity in a fabric, eg inside a curtain hem. Many caravan owners have done this to make magnetic curtains that can easily be attached and removed.