Plasma cutting -- "the
poor man's laser:"
From the very first time I was able to get two stepper motors to work
in concert to draw on an egg's surface, I realized that the exact same
process could be used for laser cutting. Unfortunately, the cost of
laser units with enough power to cut metal is stratospheric. By chance,
a contractor friend who was over for dinner noticed a steel sculpture
that my wife and I had recently bought and mentioned something like
"must have used a plasma cutter." He explained its ability to cut
any type of metal, using only compressed air and electricity-- and its
relative affordability (small units start ~$500). Two years (and a few
welding classes at Dunwoody Institute) later, I purchased this tool.
I constructed a large-scale table dedicated to cutting in the summer
of '94, and a year later, added the ability to cut cylinders.
Essentially, it works by creating an arc between the electrode in the
torch head and the piece to be cut. Compressed air forces this arc through
a tiny (~1mm) hole and produces a jet of plasma (~29,000 degrees F.,
too hot for atoms to hold on to their electrons). This narrow plasma
jet instantly melts and blows clear through the metal plate. An awesome
sight-- seen through a shade 12 welding lens!
The combined flat and cylinder cutting rig at "the Farm:"
Having the capability to cut metals under the control of computer aided
design (CAD) allows for a wide range of sculptural possibilities (steel