To break the arc, just release the trigger. This breaks the welding circuit and also de-energizes the wire-feed motor. If the wire electrode sticks to the work when it strikes the arc, or at any time during welding, release the trigger and clip the wire with a pair of pliers or side cutters. A properly established arc has a soft, sizzling sound. The arc itself is about 1/4 inch long, or about one-half the distance between the gun nozzle and the work. When the arc does not sound right, you may need to adjust the wire-feed control dial or the welding machine itself. For example, a loud, crackling sound indicates that the arc is too short and the wire-feed speed is too fast. Correct this by moving the wire-feed speed dial slightly counter- clockwise. This decreases wire-feed speed and increases arc length. A clockwise movement of the dial has the opposite effect. With experience, you will soon be able to recognize the sound of the proper length of arc to use. The proper position of the welding torch and material is important. The flat position of the material is preferred for most joints because this position improves the molten metal flow, bead contour, and gives better gas protection. The alignment of the welding wire in relation to the joint is very important. The welding wire should be on the center line of the joint if the pieces to be joined are of equal thickness. If the pieces are unequal in thickness, the wire may be moved toward the thicker piece. Correct work and travel angles are necessary for correct bead formations. The travel angle may be a push angle or a drag angle, depending upon the position of the gun. If the gun is angled back toward the beginning of the weld, the travel angle is called a “drag” angle. If the gun is pointed ahead toward the end of the weld, the travel angle is called a “push” angle. When the gun is ahead of the weld, it is referred to as pulling the weld metal. If the gun is behind the weld, it is referred to as pushing the metal. The pulling technique is usually best for light gauge metals and the pushing technique for heavy materials. Generally, the penetration of beads deposited with the pulling technique is greater than with the pushing technique. Furthermore, since the welder can see the weld crater easier in a pulling action, he/she can produce high quality welds more consistently. On the other hand, pushing permits the use of higher welding speeds and produces less penetrating and wider welds. WELDING SAFETY PRECAUTIONS Accidents frequently occur in welding operations, and in many instances, they result in serious injury to the welder or other personnel working in the immediate area. What many welders fail to realize is that accidents often occur NOT because of a lack of protective equipment, but because of carelessness, lack of knowledge, and the misuse of available equipment. You, the welder, should have a thorough KNOWL- EDGE of safety precautions relating to the job. But that is not all. You should also consider it a responsibility to carefully OBSERVE the applicable safety precautions. In welding, being careless can cause serious injury not only to yourself, but to others as well. Bear in mind that safety precautions for the operation of welding equipment vary considerably because of the different types of equipment involved. Therefore, only general precautions on operating metal arc-welding equipment are given here. For specific instructions on the operation, maintenance, and care of individual equipment, use the equipment manu- facturer’s instruction manual as a guide. In regard to general precautions, know your equipment and how to operate it. Use only approved welding equipment, and see that it is kept in good, clean condition. Before you start to work, make sure that the welding machine frame is grounded, that neither terminal of the welding generator is bonded to the frame, and that all electrical connections are securely made. The ground connection must be attached firmly to the work, not merely laid loosely upon it. Keep welding cables dry and free of oil or grease Keep cables in good condition, and, at all times, take appropriate steps to protect them from damage. If it is necessary to carry cables some distance from the machines, run the cables overhead, if possible, and use adequate supporting devices. When you use a portable machine, take care to see that the primary supply cable is laid separately so that it does not become entangled with the welding supply cable. Any portable equipment mounted on wheels should be securely blocked to prevent accidental movement during the welding operations. When you stop work for any appreciable length of time, be SURE to de-energize the equipment. When not in use, the equipment should be completely disconnected from the source of power. 15-36