The Bernardos arc is also used to cut metals. Its adaptation to metal cutting is of recent date. The arc is held stationary over the plate until the metal is melted in one place. This melted metal is ladled or poured out of the hole by tilting the plate. To obtain a clean-cut hole, it is best to reverse the plate and complete the hole from the other side. If the arc can be manipulated on a horizontal plane or held underneath the plate, the hot metal will flow out of the melt hole of its own accord. A cut in the metal plate is made by advancing the arc along the line of cutting as fast as the metal melts.

This cutting property of the Bernardos arc is somewhat similar to the oxy-acetylene torch (see page 75). The arc is not so efficient as the acetylene torch, however. The latter makes a cleaner and smaller cut and clears the metal away as the flame advances. The cutting arc has been used to cut down the steel piers of the Ferris wheel, for thawing the taps of frozen-up blast furnaces, for cutting off parts of castings, and also for mending cracks in castings.

Mr. Auel1 gives the following table of data for the cutting arc as approximate:

Bernardos Process, Burning Hole In Wrought-Iron Plate2