What should be done before applying body filler?

What should be done before applying body filler?

• A. Clean and sand the surface
• B. Apply primer
• C. Weld the area
• D. Mask the area

Answer: (A)

A clean, dry, and properly roughened surface is essential for body filler to bond. Contaminants such as oil, wax, or old paint create a barrier that prevents the filler from sticking, so the area must be cleaned and degreased before anything else. Removing rust and loose material and then lightly sanding with a coarse grit (to create a rough key) gives the filler something to grab onto, ensuring a strong, long-lasting repair. Masking or priming come after the filler is applied and cured, since primer can trap contaminants if placed before the filler. Welding might be part of metal repair in some cases, but it isn’t a preparatory step for bonding filler. Clean and sand first to ensure proper adhesion and a smooth repair profile.

A clean, dry, and properly roughened surface is essential for body filler to bond. Contaminants such as oil, wax, or old paint create a barrier that prevents the filler from sticking, so the area must be cleaned and degreased before anything else. Removing rust and loose material and then lightly sanding with a coarse grit (to create a rough key) gives the filler something to grab onto, ensuring a strong, long-lasting repair. Masking or priming come after the filler is applied and cured, since primer can trap contaminants if placed before the filler. Welding might be part of metal repair in some cases, but it isn’t a preparatory step for bonding filler. Clean and sand first to ensure proper adhesion and a smooth repair profile.