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Contour Mapping: Keeping Body Repairs from Looking Like Repairs

Fixing a dent or a scratch doesn’t require a repair in just that area. Even minor imperfections can stand out, creating visible differences between original surfaces and the repair. People in the industry call this “contour mapping.” Like the elevation lines on a topographic map, these shifts in paint and surface quality result in dramatic transitions that draw a circle around repairs. Avoiding these imperfections takes planning and skilled work to shape and blend surfaces in a way that make paint and body work disappear.

Straightening Up Dent Repairs

Metal body panels don’t have memory: when they’re dented, they won’t pop back into place. To fix dents, technicians must carefully bend the metal just enough to match the panel’s original shape.

Paintless dent repair can be done from the inside or outside of the vehicle. If there is space behind the panel that’s easy to access, a lever can be used to push down on the metal from the back side, gently massaging it back into shape. For outside repair, technicians will typically use a glue puller. This uses small plastic pegs that are glued to the surface of the panel and then pulled off using a lifter. It does “pop” the panel into place, but it takes several small pulls to reshape the surface and eliminate the dent.

With either type of repair, the metal must be bent from the furthest edge of the dent inward. If the bend is started anywhere inside the dent, it leaves a small ripple that is all but impossible to remove without stripping the paint and applying a filler.

Heavier damage can be removed by welding tabs onto the panel and pulling them out using slide hammers. Once the panel is back to its original shape, the tabs are cut off and the surface is ground flat for paint. The panel is bent from the center of the damage, but it may still need paintless repair techniques or body filler to get a smooth finish. If the slightest amount of extra metal is left over, it will show up beneath the paint.

Body filler and Clearcoat Paint 

Body filler is great for filling metal surfaces that have eroded from rust and to remove minor imperfections that can show up in paint, while glazes can fill in imperfections in clearcoat without respraying the panel. However, since filler and glazes are relatively soft, using the same sanding techniques applied to the rest of the panel can lead to deep scratches. If there’s a slight misstep, the filler must be reapplied and resanded.

Light scratches can be filled in by removing and applying a new layer of clearcoat, or by applying a glaze over the existing paint. When repairing minor damage, the surrounding area is covered to protect it from overspray. This allows just the area being fixed to be repainted, saving time and money. However, each paint job is slightly different due to changes in paint consistency, temperature and humidity. Simply repairing, painting and sanding a small section will result in a finish that will be different from the surrounding panel, even if the new paint color is an exact match to the original paint. To prevent this, the transition is feathered in, sanding an area that’s far larger than the site of the repair. The technician starts with a coarse grit sandpaper direction over the repair, covering larger and larger areas with finer paper and eventually polish. This creates a uniform surface that blends together the new and old paint finishes.

Make It Seem Like It Never Happened 

When you want quality collision repair that doesn’t look like a repair, bring your car to Merton Auto Body. We’re I-CAR certified, our techs are ASE certified, and we use the industry-leading Spies Hecker paint system, so we have the tools and techniques to make your car look like new. With over 70 years repairing cars in the Lake Country area, you’ve probably seen our work without realizing it. Our shop is a few miles northwest of Pewaukee between Lisbon and North Lake.