angle used when backhand welding is called a drag angle, or a drag travel angle. When the forehand welding method is used, the welding end of the electrode points forward in the direction of travel. The travel angle for forehand welding is called a push angle. When the electrode is perpendicular to the weld axis, the travel angle is zero degrees (0°). Restarting the Arc An arc may be stopped intentionally to change electrodes or make other adjustments. It may also stop due to faulty welding techniques. A weld bead that is stopped for any reason ends with a large arc crater. To complete the weld bead, the arc must be restarted. The restarted weld bead must melt and completely fi ll the crater from the stopped weld bead. The ripples in the weld bead must be evenly spaced across the stopped and restarted beads. When restarting the arc, proceed as follows: 1. Restrike the arc about 3/8″ (10 mm) ahead of the old crater. 2. Move backward rapidly until the rear of the new weld pool touches the rear of the old crater. 3. Move forward as soon as they touch to complete the weld. See Figure 12-13. Drag Welding Iron powder electrodes, such as the E7018 or E7024, have extremely thick coverings. Electrodes with thick coverings can be used for drag welding. Drag welding is a welding technique in which the electrode covering is in contact with the base metal. Goodheart-Willcox Publisher Figure 12-11. Travel angle is measured from the electrode axis to a line perpendicular to the weld axis in the plane defined by the weld axis and the electrode axis. A—Travel angle for a butt joint. B—Travel angle for an inside corner joint. Goodheart-Willcox Publisher Figure 12-12. Work angle is measured from a line perpendicular to the major or nonbutting surface to the plane containing the weld axis and the centerline of the electrode. The work angle for an inside corner joint is shown here. Weld axis Perpendicular to weld axis Plane defined by weld axis and electrode axis Electrode axis Travel angle Perpendicular to weld axis Nonbutting surface Travel angle Plane defined by weld axis and electrode axis B A Perpendicular to nonbutting surface Plane defined by weld axis and electrode axis Work angle Nonbutting surface 174 Section 2 Shielded Metal Arc Welding Copyright Goodheart-Willcox Co., Inc.