How to bond magnets

Magnet Bonding – There are a variety of adhesive types that bond magnets. The features and benefits of each type are listed below.  Permanent magnets are made from hard ferromagnetic materials. Magnet types vary in strength, cost, temperature and corrosion resistance. Typical magnet types include neodymium, rare-earth, samarium cobalt, AINiCo, and ferrites. All of these magnet types can usually be bonded as received but for highest strength or if the surface is contaminated cleaning with isopropanol is recommended.

Adhesives are used to bond magnets in a variety of industries; most notable are electric motors and speakers.  See the complete line of electric motor adhesives and speaker adhesives.

Motor magnet bonding

Epoxy adhesives – one and two component epoxy adhesives form strong resistant bonds to various types of magnets.  Ask Permabond about specialty high-temperature motor magnet bonding adhesives for Class H motors.

Structural acrylic adhesives – surface activated acrylic adhesives are often preferred for high-speed motor production due to the very fast set times.  Alternatively, two component external mix systems are available for a one step process.

Examples of Permabond surface activated acrylic line include:
The adhesive is applied to one surface, and the initiator is brushed or sprayed onto the other surface.  Upon assembly, strength development
occurs rapidly.  NOTE: Permabond TA437 can be used without
the initiator, providing at least one surface is metal, and the process can allow for 5 to 10 minutes of fixture time before moving.

Cyanoacrylate adhesives offer high strength bonds which are formed very quickly. Should you require high impact strength or resistance to polar solvents, epoxy or structural acrylic adhesive would be preferred.

Permabond 910 metal bonding adhesive which has a service temperature up to 195 degrees F (90C) and Permabond 737 toughened adhesive for improved impact resistance with a service temperature of 250 degrees F (120C).  Permabond 820 resists 390 degrees F (200C).  Permabond 820 resists 390 degrees F (200C).

For higher temperature resistance (up to 482 degrees F(250C)) Permabond 922 can be used with a secondary heat cure schedule as follows:

1) Parts are bonded and clamped at room temperature for four hours.
2) The clamped parts are then heated at 150°C (302°F) for two hours.
3) After two hours, the bond will be thermally resistant up to 250°C (482°F).

NOTE: Without the secondary heat cure activation of the high-temperature resistance properties, Permabond 922 will only resist temperatures up to 180 degrees F (82C)



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