Brake cleaner residues before welding should be removed before welding.

• A. True
• B. False
• C. Not specified
• D. Only with ventilation

Answer: (A)

Brake cleaner residues on the work surface must be removed before welding. The solvents can leave films or vapors that contaminate the weld pool as the metal melts, leading to porosity, lack of fusion, and a weaker weld. Some cleaners also contain chlorinated compounds that can produce toxic gases when heated. Thoroughly cleaning and allowing the surface to dry ensures proper metal-to-metal contact and a clean weld, while ventilation helps with fumes but does not substitute for removing the residue.