Uneven buildup and burnthrough are often called ____________.

• A. porosity
• B. grapes
• C. undercut
• D. craters

Answer: (B)

In GTAW, bead quality hinges on how evenly the weld pool fills and solidifies. When heat input is not controlled well, the weld can build up unevenly and burn through in spots, creating a surface that looks like a cluster of raised lumps—resembling grapes. This grape-like, irregular bead is the term used to describe that specific combination of uneven buildup and burn-through. It stands in contrast to other defects: porosity refers to gas pockets within the weld, undercut is a groove along the weld toes, and craters are pits or cracks at the end of the weld. To avoid grapes, maintain steady heat control, proper travel speed, and good shielding gas coverage so the weld fills smoothly without local burn-through.