What is a common outcome of not cleaning base metals prior to MIG welding?

Cleaning base metals prior to MIG welding is crucial, as contaminants such as rust, oil, paint, or dirt can interfere with the welding process. When the surface of the metal is not cleaned, these impurities can lead to numerous issues during welding.

One significant outcome of having unclean base metals is the increased risk of defects in the weld. These defects may manifest as porosity, where gas bubbles become trapped in the weld, weakness in the overall weld integrity, or incomplete fusion between the base metal and the weld metal. Additionally, contaminants can affect the arc stability, leading to inconsistent penetration and bead shape. This failure to achieve proper fusion and penetration often results in welds that do not meet strength requirements and can ultimately lead to premature failure of the welded joint.

In contrast, cleaning the base metals allows for a better electrical contact, improved arc stability, and a more thorough fusion of the metals, which ultimately promotes the creation of strong and reliable welds.