Differentiate between lack of fusion and lack of penetration in a MIG weld.

• A. Lack of fusion is incomplete bonding between weld metal and base metal; lack of penetration is insufficient weld depth through the joint root
• B. They are the same
• C. Lack of fusion is weld depth; lack of penetration is alignment
• D. Lack of fusion relates to color; lack of penetration relates to spatter

Answer: (A)