Causes and Cures of Common Welding defects Welding Type worm hole Defect: Blow Hole worm hole blow hole Why What to Do SMAW CO2/MAG 1.Unclean base metal surface. 2.Rusted wire or wet flux. 3.Improper spot welding or wire. 4.Excessively long arc length or insufficient gas shielding. 5.Welding in the windy surrounding without trailer shield. Welding Type 1.Wet, unclean or damaged electrode. 2.Base metal surface covered with oil, rust, etc. 3.Over travelling speed. 4.Over currents 5.Excessively long or short arc length. 6.Too thick base-metal or too fast cooling rate. Why What to Do SMAW 1.Properly maintain and store electrode. 2.Properly clean base metal prior to welding. 3.Reduce travel speed. 4.Use proper welding current. 5.Maintain proper arc length. 6.Proceed proper pre-heating. CO2/MAG 1.Properly clean base metal prior to welding. 2.Properly maintain and store wire and flux. 3.Choose wire size properly and proceed spot welding correctly. 4.Maintain proper arc length and gas flow rate. 5.Add trailer shield. 188