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Welding Objective: learn to safely use an arc welder by following safety precautions, knowing how to use equipment and tools, and having an overall general knowledge of welding Types of Arc Welders AC (Alternating Current)- low voltage welder that places a limit on types of electrodes used. DC (Direct Current)- has more advantages and a wider variety. It can be used with no power source. (Gasoline Engine) AC/DC- (not back in black)- but a combination welder that gives you all of the advantages of arc welders. Equipment and Tools 1. Ground Clamp- clamps to the metal being welded or to the metal table. 2. Electrode Holder- holds the electrode (rod) to be used while welding. Equipment and Tools 3. Head Shield (Welding Helmet)consists of a #10 lens that protects the face and eyes from UV rays and spatter. 4. Leather Welding Gloves- Protects hands from rays and spatter. Equipment and Tools 5. Leather Apron- protects clothing from rays and spatter. 6. Wire brush and Chipping Hammercleans excess slag and chips the slag. Equipment and Tools 7. Tongs and Pliers- used to carry hot metal. 8. Welding Table- used when welding small projects. Two Types of Electrodes 1. Bare or Lightly Coated- usually used by beginners, and has little or no flux. 2. Shielded Arc or Heavy Coated- has a flux coating that usually forms slag on the bead to produce a stronger weld. Sizes of Electrodes Sizes will range from 1/16” – 3/16” We normally use 1/8”. Identifications of Electrodes 1. By a four-digit number. 2. By the color of the flux. Example: 6013 60- tensile strength (thousand lbs./square inch) 1- Welding position 3- Special Characteristics How Do I Know What Kind of Electrode I Need? 1. Kind of metal to be welded. 2. Kind of weld and type of joint being welded. 3. Type of welding machine being used. 4. Position of the weld. 5. Thickness of the metal being welded. 6. Required strength of the welding joint. 7. Speed of travel. Striking An Arc Methods: 1. Scratching Method- used by beginners, move the electrode across the metal at an angle, as if you’re striking a match. 2. Tapping Method- Move downward in a vertical motion. As soon as the electrode touches the metal withdraw to maintain the correct arc length. Freezing Effect Sometimes when welding, the electrode will stick to the metal. Don’t panic!!! Simply move the electrode back and forth to release. If this doesn’t work unclamp the electrode from the electrode holder and turn the machine off. Running the Bead Strike the arc and form a puddle. Maintain the width of the puddle throughout the bead