What is the recommended action when there is a significant amount of contamination on the base metal?

Performing thorough cleaning of the base metal is essential when there is a significant amount of contamination. Contamination can manifest as rust, grease, paint, or other foreign materials that can adversely affect the quality of the weld. If the base metal is not properly cleaned, it can lead to weak welds, increased porosity, and overall inferior weld integrity.

The purpose of cleaning is to ensure that the weld area is free from impurities that could interfere with fusion and affect the mechanical properties of the weld joint. Different materials and types of contaminants may require specific cleaning methods such as grinding, sanding, chemical cleaning, or using solvents. Ensuring a clean metal surface allows for better arc stability and weld quality, which is crucial in Gas Tungsten Arc Welding (GTAW) processes known for their precision and quality demands.