By Maya Austen
Updated Mar 24, 2022

A permanent magnet is a piece of metal that retains magnetic properties without an external field. While the term “permanent” implies lasting magnetism, these materials can lose strength—especially when heated above their Curie temperature (Curie point) or exposed to strong opposing fields. Restoring magnetism involves cooling the metal (if heated) and re‑exposing it to a controlled magnetic field.

Step 1: Create a Solenoid

Wrap insulated copper wire tightly around the demagnetized metal, forming a solenoid. Each turn strengthens the magnetic field that will be generated. Leave at least six inches of free wire at each end to connect to a power supply.

Step 2: Connect the Power Supply

Attach the free ends of the wire to the terminals of a DC power supply. A stable, low‑voltage supply (typically 5–12 V) is sufficient for most hobbyist applications.

Step 3: Activate the Current

Turn on the power supply to pass current through the solenoid. This creates a uniform magnetic field that will realign the magnetic domains within the metal.

Step 4: Timing

Maintain the current for ten seconds, then switch it off. The brief pulse allows the magnetic domains to settle into a new, stronger alignment.

Step 5: Test the Result

Hold a nail or paper clip near the metal. If it attracts, the magnet has been successfully restored. If not, increase the field strength by adding more turns to the solenoid and repeat the process.

Materials Needed

• Demagnetized permanent magnet
• Insulated copper wire (spool)
• DC power supply (5–12 V)

Alternative Method: Stroking Technique

For weaker magnets, the stroking method can be effective. Using a strong, aligned permanent magnet, stroke the target magnet in a single, unidirectional sweep. Repeat from one end to the other until the magnet regains attraction to a nail or paper clip. Avoid back‑and‑forth strokes, as they can cancel alignment.