Which visual sign indicates porosity in a weld?

• A. Cracks along the weld.
• B. Excessive spatter around the weld.
• C. Tiny holes or rough interior surfaces along the weld.
• D. A perfectly smooth, uniform surface.

Answer: (C)

Porosity shows up as trapped gas forming tiny holes or voids in the weld metal as it solidifies. The clearest visual sign is small holes or a rough interior surface along the weld, which indicate those gas pockets. Cracks along the weld point to cracking, not porosity. Excessive spatter is molten metal ejected around the bead, not gas pockets inside the weld. A perfectly smooth, uniform surface suggests a sound weld with no porosity. Porosity can arise from moisture on the electrode, dirty metal, insufficient shielding gas, or improper welding parameters, all of which can introduce gas that becomes pores in the weld.