What is a common shielding gas mixture for MIG welding aluminum?

In MIG welding aluminum, a common shielding gas mixture is 100% Argon. This is because Argon is an inert gas that effectively protects the molten weld pool from contamination by atmospheric gases like oxygen and nitrogen, which can lead to defects in the weld. Argon's physical properties, such as its greater density compared to air, allow it to create a reliable shielding layer over the weld area, ensuring that the aluminum is shielded properly throughout the welding process.

Using pure Argon for aluminum MIG welding enhances the stability of the arc and helps achieve a smooth, clean weld bead. It contributes to better weld penetration and reduces the risk of porosity, which can compromise the integrity of the weld.

Other gas mixtures, such as those containing Carbon Dioxide or Helium, do not provide the same level of protection or produce the desired arc characteristics for aluminum. Using a combination of gases might be suitable for specific applications or materials, but pure Argon remains the most widely accepted choice for aluminum welding due to its effectiveness in creating high-quality welds.