Which option describes the open butt joint approach in this context regarding burn-through avoidance?

• A. Double pass welds
• B. Stitch welds
• C. Lap welds
• D. Full-penetration weld

Answer: (B)

Controlling heat input is the key for open butt joints to avoid burn-through. Stitch welds apply the weld in short, spaced segments, which lets the metal cool between passes. That cooling time reduces the chance that heat penetrates through the sheet and creates a burn-through, especially on thin collision-repair panels. It also helps minimize distortion by not dumping a continuous heat source along the seam.

In contrast, a continuous or longer weld sequence adds more heat and increases the risk of burn-through on thin metal. Lap welds aren’t ideal for a butt joint and can cause thickness buildup and distortion. A full-penetration weld would push heat all the way through the joint, making burn-through even more likely on thin sheets. So the stitch weld approach best supports burn-through avoidance in this context.