HOW TO MAKE AN ARC LIGHT
Copper electrode holders
Heavy duty switch
Nichrome wire resistor
(CAUTION: VERY HOT) !
can build Sir Davy’s
invention out of
simple materials such
as copper and carbon
(Figure A), powered by
a 12V or 18V battery
instead of Davy’s
primitive voltaic cells.
He used charcoal, but
nowadays it’s easiest
to get your carbon
rods straight out of
(Figure B). When
electricity is applied,
small bits of hot
carbon jump across
the gap, producing a
arc (Figure C).
MATERIALS AND TOOLS
Please read before beginning the project.
» The arc light produces strong ultraviolet light
that can damage skin and eyes. For safety, use arc
welding style eye and skin protection including
gloves, long sleeves, and a helmet with #7 shade
or darker when using the arc light.
» The Nichrome wire and copper electrode holders
get extremely hot. Be very careful around them!
There is little to no shock hazard associated with
12- and 18-volt batteries.
Photography by William Gurstelle
» This is a demonstration device only and should
only be operated intermittently and for brief
intervals. Running the arc lamp for too long can
damage your battery or battery charger. If using
a battery charger, check the ammeter on your
charger to make sure the circuit is not shorted.
If it is, or nearly is, use a longer Nichrome wire.
12-volt battery charger with ammeter, or an 18-volt
battery from, say, a portable power drill
Carbon rod, about ¼" diameter, ½" lengths ( 2)
The easiest way to obtain a pure carbon rod is to
cut open a regular non-alkaline AA, C, or D cell
battery with a Dremel tool or hacksaw. Such
batteries are usually labeled “heavy duty” or “
non-alkaline.” Cut off the top and carefully remove
the carbon rod from the black, greasy packing
that surrounds it. The packing material will stain
hands, clothes, and work surfaces, so wear rubber
gloves and cover surfaces with newspaper.
Miscellaneous wood pieces
20- to 24-gauge Nichrome wire, 2'
Porcelain insulators ( 2) Electric fence insulators
Nuts and bolts to mount insulators to wood base
Heavy-duty flexible stranded lamp cord
Small copper spring clamps ( 2)
¼"-diameter copper tubing, 1½" lengths ( 2)
Heavy-duty on/off switch aka knife switch
Posable alligator clips I used clips from a discarded
“third hand” tool, but you could easily make them
by soldering an alligator clip to a stout copper wire.
Miscellaneous wood screws
Eye protection such as an arc welding helmet