2c. Wrap electrical tape around the rod to completely cover the
area between the 2 squares. This adds extra insulation between
the coil and rod, for safety.
2d. Leaving 2"– 3" of length free at the start and finish of the coil,
tightly wind the full spool of #18 magnet wire (approximately
200') around the rod between the 2 squares. These lengths of
wire will connect the coil to the 120V AC power source later.
Once the coil is done, use electrical tape to prevent the wire from
3. CUT THE RINGS
Use a hacksaw or similar tool to cut several rings from the aluminum tubing. They should be at least 1" long, but you can cut
different sizes to experiment. You’ll need a whole bunch; the rings
can shoot up so high that you might lose some!
You can try cutting rings from other materials, although steel or
iron tubing won’t work well because it’s not only heavier and has
a lower electrical conductivity than aluminum, it’s also inherently
magnetic and will be attracted to the coil during those 2 instances in every cycle when the voltage isn’t
changing. Copper tubing conducts electricity even better than aluminum, but it’s also heavier than aluminum and doesn’t react physically (due to inertia) as strongly to the changing magnetic field as aluminum.
Rings cut from any type of tubing should have an inside diameter of q"– 1".
Optional: To make the rings easier to see and photograph, wrap the outsides with brightly colored tape.
4. WIRE IT TOGETHER
This project has only 3 electrical parts: the plug (P1 in the schematic at right), the coil (L1), and the fuse (F1). The time-delay
7A fuse is required to keep the coil from heating to possibly
dangerous levels if you leave the power-strip switch on.
4a. Use a knife or sandpaper to scrape 1" of enamel insulation off
each end of the coil’s magnet wire.
F1 (7A, time-delay)
P1 BLK or
Connect to steel rod