How to Do Automotive Body Work | Dents, Scratches & Rust

Automotive body work means repairing dents, corrosion, and surface damage, then restoring the panel to a refinish-ready condition.

Professional-looking body work comes down to preparation, not talent. The difference between a repair you can paint over and one you have to redo is almost always in how thoroughly you clean, scuff, and feather the surface before filler ever touches it. If you’re tackling collision damage, corrosion, or deep scratches on your own vehicle, the process below follows the standards ASE collision-repair programs teach, and it works for everything from a door ding to a rusty quarter panel.

How To Prep The Repair Area The Right Way

Every successful repair starts the same way: a clean, fully prepped surface. ASE’s collision repair standards require inspecting the work order and confirming you understand what repairs are needed before you start. From there, the sequence is straightforward.

Wash the entire vehicle with car-wash soap or a pressure washer, including the wheel openings, then rinse and dry it completely. Any wax, grease, or road film left on the panel will ruin filler adhesion later. After the wash, go over the repair area with a regionally approved surface cleaner and a clean towel, and dry it again.

Avoid the most common mistake here: sanding only the visible damaged spot. You need to remove paint well beyond the damage so the filler has something solid to bite into.

Body Filler: The Step Order That Works

With the surface clean, you can move into the filler phase. Removing paint starts with a DA sander and P80 grade paper. Extend the abraded area 2 to 4 inches beyond the visible damage, and hit the edges, body lines, and recessed areas with a general-purpose scuff pad to remove any remaining coating. Blow the dust off with clean, dry air and re-clean the surface.

One compatibility warning matters more than any other: check your vehicle’s OEM Technical Service Bulletins before applying filler. Some makes and models require epoxy primer before body filler, so this process is not universally interchangeable across vehicles. When you’re ready to mix, follow the filler manufacturer’s recommendations exactly.

• Mix and apply body filler per the manufacturer’s instructions.
• Block sand with P80–P100 paper, reapply filler as needed, then finish with P180 paper.
• Clean with dry air and a tack cloth.
• Mix and apply glaze filler over the entire repair area, from paint edge to paint edge, and let it cure completely.
• DA sand the featheredge with P280–P320 paper and blow off the dust.

When the filler work looks right, do a final inspection to check for pinholes, low spots, or rough edges. This is your last chance to fix problems before the panel goes under primer and paint.

Safety Gear And Shop Regulations

Body work is not just dusty—it is hazardous. ASE’s standards require selecting and using proper personal safety equipment and taking precautions with hazardous operations and materials under federal, state, and local regulations. That means respirators rated for paint and filler dust, chemical-resistant gloves, and eye protection, not just a dust mask from the hardware store.

The work area itself is regulated too. OSHA hosts dedicated autobody repair and refinishing resources, including materials on air toxics and shop safety for collision repair facilities. If you’re working at home, follow the same principles: ventilate aggressively, keep solvents away from ignition sources, and dispose of rags soaked in filler or paint properly—they can self-ignite.

One more thing to keep in mind: structural repair is specification-driven, not guesswork. If the collision damaged more than a panel, the vehicle needs to be examined against the manufacturer’s dimensions and appropriate industry standards before any cosmetic work begins. If the structure is bent or pulled, no amount of filler will fix it safely.

Before you buy materials, check our tested auto body supply recommendations to see which fillers and sanding kits actually hold up in real use.

What Separates A Lasting Repair From A Quick Fail

Three mistakes cause nearly every failed DIY body job: skipping OEM guidance, failing to clean the surface before abrasion, and sanding only the visible damage instead of extending beyond it. Avoid those, and you’re already ahead of most first-timers.

Patience is the real differentiator. Let the glaze filler cure completely before sanding it, and take the time to stretch the sanded area well past the damaged zone. You cannot rush the cure cycle or the featheredge and still get a panel that looks right under paint.