The protective gas flow rate is set too high: Make sure that the flow rate is set correctly. 2 - 3 liters/min are completely sufficient (this corresponds to approximately 0.4 bar)! The electrode is clamped too long: The shorter the electrode protrudes from the handpiece, the better the protection provided by the argon. Wrong shielding gas, insufficient quality: We recommend pure argon (Ar 4.6), with a purity of at least 99.996%, without additives. There is dirt on the workpiece: Any type of dirt, polishing compound, paint, electroplated coating, etc. will burn off during welding and often leave behind large amounts of soot. Clean the workpiece thoroughly before welding. The alloy of the workpiece is contaminated: If the metal of the workpiece has inclusions or the alloy contains metals that burn at low temperatures (zinc, lead, tin, etc.), this may cause sooting.