Exothermic Cutting Technique (Cast Iron, Stainless Steel and Non-Ferrous Metals).
Cast iron, stainless steel and non-ferrous metals do not oxidize; therefore, underwater cutting becomes a melting process. The exothermic process develops tip-temperatures in excess of 10,000 degress F, which is sufficient to melt these materials with ease. The following technique is recommended:
a. Keep the tip firmly buried in the puddle. Using a sawing motion, manipulate the electrode in and out of the cut.
b. To cut thick, non-ferrous metals, create a puddle and keep the electrode tip slightly below the surface of the molten metal. Every few seconds, push the cutting electrode deeper into the molten pool to wash out and blow the molten metal through. Increase the oxygen pressure at the electrode tip to 110 psi for metals over 3 inches in thickness