Why do we need an electrode to weld, a bare wire can also melt in the Arc and form a welded joint?
The difficulty encountered when trying to weld with bare wires is that the melted metal in the arc and work piece molten crater is exposed to the atmosphere causing the metal to oxidise leading to loss of ductility. In addition nitrogen pick-up causes embrittlement. The arc also tends to be unstable, burn at a low rate, is less concentrated and therefore has less penetrating power. The above facts, chemical and electrical are the reasons for the coating of the electrodes. It is essential that the molten metal is protected from the atmosphere. The arc has to be stabilized and concentrated to make it more effective. In the early days of World War I, arc welding was used in England. The electrodes were made by tightly wrapping a high grade asbestos cloth around a lime washed wire. America supplied electrodes by replacing the asbestos with cotton cloth dipped in water-glass (sodium silicate); a standard fireproofing substance, to minimize flaming of the cotton cloth in the arc. These elect
