Which shielding gas is NOT commonly used with GTAW?

• A. Argon
• B. Helium
• C. Neon
• D. A mixture of Argon and Helium

Answer: (C)

GTAW shielding gas must protect the weld pool from the atmosphere while shaping the arc and heat input. Argon is the standard choice because it provides a stable arc and good protection for a wide range of metals. Helium is used when more heat is needed or when welding materials with high thermal conductivity, delivering a hotter arc and deeper penetration, though at a higher cost. A mix of argon and helium lets you tailor the arc to balance stability and heat input for specific applications. Neon isn’t commonly used for GTAW shielding because it’s expensive and tends to offer poorer arc stability with limited practical benefits for typical welding, making it impractical compared with the other options.