How to Magnetize Rebar

Rebar is a type of steel bar used in construction and industry. The word "rebar" is a portmanteau (blend) of the words "reinforcing bar." Ordinarily, rebar is not magnetic, but it can be magnetized. Since it is made of steel---a hard alloy of iron, rather than soft pure iron---rebar is an ideal material for this purpose because it tends to remain magnetized (i.e., it has "remanence"). Placing rebar in a strong magnetic field will magnetize it, or the effect can be achieved by stroking the rebar with a magnet.

Things You'll Need

• Small piece of steel rebar
• Permanent magnet such as a strong refrigerator magnet
• Small bits of iron or steel (iron filings, small hardware, etc.)

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Instructions

1. • 1

     Lay the rebar on a flat, non-magnetic surface, such as a wooden table.

   • 2

     Stroke the rebar lightly with the permanent magnet (use the strongest magnet you can find). Move all the way from one end of the rebar to the other end. Hold the magnet very close to the rebar while stroking; it is not necessary for it to continuously touch the rebar, because the magnetic effect does not depend on physical contact.

   • 3

     Repeat the stroking motion, always in the same direction, about 20 times.

   • 4

     Place the rebar close to the iron filings or small pieces of hardware to test whether it has been magnetized yet. If this material is strongly attracted to the ends, then you have successfully magnetized the rebar. If not, then continue stroking the rebar with the permanent magnet, retesting it periodically.