What is back purging and when is it necessary in aluminum TIG welding?

• A. Back purging exposes and protects the far side of the weld area from oxidation, preventing oxide formation in enclosed or thick-walled aluminum welds; requires an intact purge line and inert gas supply.
• B. Back purging is optional and only used on non-aluminum welds.
• C. Back purging uses oxygen to prevent oxidation.
• D. Back purging is accomplished by post-weld cleaning.

Answer: (A)