If the end of the filler rod is removed from shielding gas protection, ____.

• A. It will oxidize rapidly
• B. Turbulence will increase
• C. Air will mix with the shielding gas
• D. It will cool rapidly

Answer: (A)

Shielding gas keeps the weld area and any filler metal protected from the atmosphere. When the end of the filler rod is not inside that gas shield, the molten filler metal is exposed to oxygen in the air and oxidizes rapidly. Oxidation leads to oxide films on the filler metal and can contaminate the weld, reducing strength and quality. The other ideas aren’t the direct consequence of losing protection at the rod tip: turbulence isn’t guaranteed just by removing protection, air mixing with shielding gas depends on flow and setup, and cooling isn’t inherently faster just from exposure to air. Keep the filler rod tip within the shielding gas envelope as you feed it into the weld to prevent oxidation.