... , crackle, abrasion, wear and tear, miscalculation in manufacture repair metal tools/ better than Spot welder, Arc welder / cold ... defect in manufacture, welding defect.3. Suitable material can repair:Aluminum material, aluminum alloy, copper material, copper alloy, ... bottom, deep cavitiy, flat surface, and etc.Welding part:Welding application: repair metal tools/ better than Spot welder, Arc welder ...