Carbon Arc cutting/gouging
From time to time, mistakes are made in a weld seam, or a repair to a weld will be needed. It can be quite time consuming grinding and cutting the affected area to get down to good metal. Especially in a field repair situation, something may need to be rapidly cut or gouged away. The best solution is the Air-Carbon Arc Cutting torch. It’s a relatively simple process. Though it’s not as neat as a plasma or even an oxyacetylene torch, the Air-Arc process is rapid. It can remove a lot of metal in a very short amount of time. The Air-Arc process however, needs plenty of amperage to do the job properly. A simple high amp output Constant Current power source such as a stick welder is used. The usual minimum amperage required is 300 amps, though smaller electrodes will demand less amperage. The carbon arc torch is very similar in appearance to the standard tong type electrode holder. However, it also has a starting button and an air hose that provides a “jet” of air from the torch. Instead of a wire electrode, a carbon electrode is used, which provides a super hot arc. It is fairly slowly consumed, but it does wear. The arc is struck and held short while the air is turned on. The air pressure starts to wash away the metal, as the torch is held at a relatively flat angle. This is technically referred to as “gouging”. Carbon electrodes can be a little expensive, particularly the copper clad ones which last longer, and provide a little more uniformity in the cut. The torch oscillated gently around directing the arc and the air to spread out the cut. If a deep cutting action is need the torch should be rotated to a steeper angle. Slag and sparks come with the job, so extreme caution must be used to prevent the wash of slag being directed toward any flammable surface. Also good personal protective equipment is a must to prevent accidental back splash.