Pot Magnets 101

1. What is a permanent magnet?

A permanent magnet produces a steady magnetic field without electricity. It’s made from ferromagnetic alloys like iron, nickel, cobalt, or rare earth compounds. It retains strength over time unless damaged by heat, impact, or corrosion.

2. What is a pot magnet?

A pot magnet is a permanent magnet housed in a steel cup or channel. The housing amplifies magnetic force at the mounting surface and protects the magnet from impact and stray fields. Pot magnets are defined by their steel housing, not the magnetic core—the magnet inside can be neodymium (rare earth), ceramic, or alnico, each offering different strength and environmental characteristics.

3. What is a rare earth magnet?

Rare earth magnets are made from alloys containing elements like neodymium, samarium, and dysprosium—metals with exceptional magnetic properties. Neodymium-iron-boron magnets deliver unmatched strength in compact sizes. Their high energy density makes them ideal for demanding industrial, mechanical, and consumer applications.

4. How are permanent magnets made?

Permanent magnets are built through a multi-step process. First, magnetic alloys—like neodymium, iron, and boron—are ground into fine powder. This powder is pressed into shape while exposed to a magnetic field, aligning the particles. The compacted form is then sintered at high temperatures to fuse the structure and lock in magnetic orientation. After cooling, the magnet is machined to final dimensions, coated for protection, and magnetized to full strength. This process creates a dense, directional magnetic field built for long-term performance.

5. What does magnet grade mean (e.g., N42, N52)?

Magnet grades indicate strength based on material quality and manufacturing. Higher grade numbers mean stronger magnets with greater pull force and resistance to demagnetization. Choose grades that match your load and environmental requirements.

6. What is pull force and how is it measured?

Pull force is the maximum strength a magnet can exert before detaching from a steel surface. It’s measured under ideal conditions—clean, flat steel with the magnet flush and perpendicular. Surface roughness, coatings, and angle reduce real-world performance.

7. How strong is the magnetic force of pot magnets?

Pot magnets can deliver pull forces ranging from a few pounds to several hundred pounds depending on size, material, and housing. Thicker, more ferromagnetic mounting surfaces increase adhesion. Always select magnets rated well above your required load.

8. How do magnets interact with coated surfaces?

Magnets adhere best to bare steel. Coated surfaces—like paint, powder coating, or plating—reduce contact and weaken pull force. The thicker or more non-conductive the coating, the greater the loss. Always test adhesion on the actual surface.

9. How do stacked magnets behave?

Stacking magnets can increase pull force, but gains aren’t linear. Each added magnet improves strength up to a point before diminishing returns set in due to field interference and alignment issues.

10. What temperature ranges can pot magnets withstand?

Standard neodymium pot magnets operate between -40°C and 80°C. Some variants with special coatings or materials can tolerate higher temperatures. Always confirm ratings before installing near heat sources.

11. Are magnets waterproof or weatherproof?

Rare earth magnets are not waterproof and will degrade if exposed to moisture. Protective coatings and housings can make them water-resistant or weatherproof for outdoor or harsh environments.

12. What coatings are available and why do they matter?

Common coatings include nickel-copper-nickel, epoxy, zinc, and rubber. They protect against corrosion, physical damage, and conductivity. Choose coatings based on exposure—wet, corrosive, or high-wear conditions require tougher finishes.

13. How do pot magnets attach to surfaces?

Pot magnets are mounted using threaded studs, countersunk holes, or adhesive backing. Fastening method depends on substrate and load. Proper mounting ensures full magnetic contact and prevents slippage.

14. Can magnets be cut, drilled, or machined?

No. Most magnets, especially neodymium, are brittle and can chip or shatter during machining. Cutting or drilling risks cracking and severe strength loss. Only modify housings, and only under expert supervision.

15. How should magnets be handled and stored?

Handle with care—rare earth magnets snap together fast and can pinch or shatter. Keep away from magnetic media and medical implants. Store in attracting pairs or closed containers. Avoid impact, heat, and moisture.

16. Will a magnet affect my smartphone?

No. Modern smartphones use solid-state drives and LCD/LED screens, which are immune to magnetic interference. Phones contain several small magnets for speakers, sensors, and vibration motors.

17. Can magnets interfere with Ethernet, WiFi, or electrical signals?

Stationary magnets emit static fields, not fluctuating currents. They do not produce electromagnetic interference and won’t affect copper cables, WiFi signals, or fiber optics.

18. What are common uses for pot magnets?

Pot magnets are used to mount signs, tools, fixtures, sensors, and cable runs to metal surfaces in shops, warehouses, vehicles, and job sites. They’re also used for door closures, magnetic bases, salvage operations, and temporary signage.

19. What affects a magnet’s lifespan?

Magnets don’t wear out like mechanical parts, but strength can degrade from heat, corrosion, impact, or stray magnetic fields. Proper handling, coatings, and dry storage preserve long-term performance.

20. What is the purpose of the cup on a pot magnet?

The steel cup concentrates and redirects the magnetic field toward the mounting surface, dramatically increasing holding power. It also protects the brittle magnet from impact, cracking, and corrosion. By shaping the magnetic circuit, the cup ensures more force at the same size—making pot magnets up to 30× stronger than bare magnets of equal dimensions.

The images below show how the steel cup contains and amplifies the magnetic field in our UHD Series and Winnie MAG pot magnets.

The steel cup of the Winnie MAG pot magnet contains and redirects the magnetic field toward the fastening surface, increasing holding power and protecting the magnet core.

The steel cup of the WUMAG-1420UHD magnet assembly shapes and focuses the magnetic field toward the mounting surface, delivering amplified force and shielding the magnet from damage.