When welding aluminum, one of the main problems or defects you’ll come across is porosity. Porosity occurs when gas becomes trapped in the weld pool. Porosity can occur when welding any metals, including aluminum.
Porosity in aluminum is caused by hydrogen, which is the only gas soluble in aluminum. If the cooling rate is too high when welding aluminum, the hydrogen becomes trapped in the metal in the form of porosity.
Prevent porosity with several measures, including ceramic anti-spatter spray. Use proper tools and cleaning methods made for aluminum, such as stainless steel wire brushes. Using an anti-spatter spray can also help prevent porosity. Because hydrogen is present in water and oils, you’ll want to select an anti-spatter that does not contain any water or oils. Ceramic anti-spatter like BorNiGuard works well to prevent porosity. Robert Lahnsteiner, of MIG WELD GmbH International, states that “ceramic spray is safe if applied correctly.”
BorNiGuard is an aerosolized high-grade ceramic coating. To help prevent porosity in aluminum, spray a thin layer of BorNiGuard before welding.