Neodymium magnets are powerful magnets that are used in many different applications. Most magnets bought from stock are nickel-plated. Nickel is an excellent choice to protect the magnet as it is highly resistant to corrosion. Unfortunately, the same great properties of nickel that make it ideal for magnet protection make it difficult for adhesives to form a chemical bond to adhere to the substrate. Additionally, nickel plating produces a surface that is extremely smooth and hard, further reducing the ability of the adhesive to form a satisfactory bond with the metal.
When using stock neodymium magnets, the types of glue that actually work are very limited. Get more here electronics assembly adhesives. The best choice is a two-part epoxy adhesive. These adhesives are mixed just before use and create their own chemical reaction to attach the magnets to another object.
Before attempting to glue neodymium magnets, users should take the time to prepare the surface to interact with the glue and create the best bond possible. Begin by cleaning and degreasing the surface of the nickel plating. This requires the use of an industrial solvent degreaser. Household detergents and alcohol do not have the degreasing power to effectively clean the magnet and prepare it for gluing. Once the grease is removed, use a 200 grit emery cloth to abrade the surface. The goal is to create a surface with enough texture for the glue to grip and without breaking through the nickel, which would allow the magnet to corrode. After sanding the surface, clean and degrease a second time. To test the preparation, put a few drops of water on it. When the water spreads to wet the surface and doesn't bead, it's ready to pick up the glue and form a strong bond. Be sure to let the surface dry before mixing the glue and attempting to stick the magnet to the surface.
The surface to which the magnet is to adhere must also be prepared to receive the magnet. Make sure it's also free of grease, dust, or other contaminants. If this surface is also extremely smooth like the nickel plated neodymium magnet, it may be necessary to grind this surface as well.
Mix the epoxy according to the package directions. Hardener and adhesive are usually mixed in equal parts. Only mix as much glue as can be used in a short time. Apply to the magnet and attach to the surface. Clamp to dry if necessary.
Stock neodymium magnets are plated with extremely hard and smooth nickel, which prevents adhesion with most adhesives. With proper preparation, the magnets will adhere to most surfaces with a high-quality, two-part epoxy adhesive.