To make sure that the machine is of sufficient size to produce the required current. Amperages required depend upon the size (diameter) of the electrode, as follows:
Compressed Air at 80 to 100 p.s.i (5.62 to 7.03 kg/cm2) and 30 to 50 cfm (0.85 to 0.99 m3/min.) is required for optimum removal of molten metal (slag) from the gouge, groove or cut. (Note: to convert p.s.i to kPa - kilopascals - multiply by 6.895). Compressed air is normally obtained from the standard shop supply, but a suitable compressor may be used (say 3 - 5 HP).
