How to Build a Magnetic Ring Launcher

Select a core for your magnetic ring launcher. This should be something that is magnetic, about 2 or 3 feet long and not too heavy--you will be holding it like a pistol for the launching. A few welding rods are excellent for this project. They are cheap and readily available. The more rods you use, the stronger the projector will be, but the more rods you have the heaver the projector will be. Glue the rods into a tight bundle and file the glue off so the bundle is smooth.

Find a ring that fits snugly around the core but slides easily. The ring will have to be made out of a diamagnetic material. In terms of magnetism, there are three kinds of material: ferromagnetic (attracted by magnets), diamagnetic (repelled by magnets) and non-magnetic (unaffected by magnets). Aluminum is the cheapest and more readily available diamagnetic material. You can buy aluminum rings in hobby shops and in large hardware stores. The strongest diamagnetic material is bismuth--a metal that looks like lead but is non-toxic. Bismuth rings work better but the rings are harder to find than aluminum rings.

Wrap the wire around 1/3 of the core (starting at one end)--leaving the other 2/3 unwrapped. The wrapping should be three or four layers. The two free ends of the wire go to the power source. It is convenient to put a switch between the electromagnet and the power source so the projector can be easily fired. Slip the ring over the core until it rests against the coils of wire. Point at a target and turn on the switch to watch the ring rush along the core and off the end of the projector toward the target.