What is the purpose of body filler?

• A. To restore smooth contours after metal repair
• B. To add color
• C. To prevent rust on body panels
• D. To increase structural strength

Answer: (A)

The main idea is that body filler is used to create a smooth, uniform surface after metal repair. When a panel has dents, irregularities, or uneven patches from dent removal or patching, you don’t paint over that directly—the finish would show every flaw. A lightweight filler is applied over the repaired area, cured with a hardener, then sanded flush so the repaired zone blends into the surrounding skin. This allows the primer and paint to lay down evenly and produce a seamless look.

It's not used to add color, and it doesn't protect against rust—that comes from proper prep and coatings like primers. It also isn't a structural material; the filler is non-structural and should be kept to thin layers (typically a small fraction of an inch) to avoid cracking. If needed, finer glazing putty is used after to address micro-scratches, followed by primer and paint.