Figure 7-53.Air carbon-arc cutting.
metal. Figure 7-53 shows the process. The equipment
consists of a special holder, as shown in figure 7-54, that
uses carbon or graphite electrodes and compressed air
fed through jets built into the electrode holder. A push
button or a hand valve on the electrode holder controls
the air jet.
The air jet blows the molten metal away and usually
leaves a surface that needs no further preparation for
welding. The electrode holder operates at air pressures
varying between 60 and 100 psig.
During use, bare carbon or graphite electrodes be-
come smaller due to oxidation caused by heat buildup.
Copper coating these electrodes reduces the heat
buildup and prolong their use.
The operating procedures for air carbon-arc cutting
and gouging are basically the same. The procedures are
Adjust the machine to the correct current for
Start the air compressor and adjust the regulator
to the correct air pressure. Use the lowest air
pressure possible-just enough pressure to blow
away the molten metal.
Insert the electrode in the holder. Extend the
carbon electrode 6 inches beyond the holder.
Ensure that the electrode point is properly
Strike the arc; then open the air-jet valve. The
air-jet disc can swivel, and the V-groove in the
disc automatically aligns the air jets along the
electrode. The electrode is adjusted relative to the
Control the arc and the speed of travel according
to the shape and the condition of the cut desired.
Figure 7-54.Air carbon-arc electrode holder with carbon electrode installed.