Before applying body filler, what should be done?

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

Answer: (C)

Getting a solid bond with body filler starts with clean, properly prepared surface. Clean the area to remove oils, waxes, dust, and any contaminants that would make the filler pull away or not cure correctly. Then lightly sand the area to create a rough, “keyed” surface so the filler has something to grip onto and the edges feather smoothly into the surrounding paint. This combination is what lets the filler stay in place and start the repair with good adhesion.

Masking the area is important, but it protects and isolates areas during work rather than preparing the adhesive surface. Primer comes after the filler is shaped and sanded to seal the repair and provide a good base for paint. Heating the area is not a proper prep step and can damage the material or cause distortion.