Thread: Aoto Body explained..

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Yes, all dents are stretched metal... Just to clarify on and off dolly.


On-dolly:





As the hammer stikes the panel with the dolly held directly beneath, the forces come together (red arrows) and the panel is compressed between the two. With nowhere else to go, the metal is forced outward (blue arrows) in the form of a stretch.


Off-Dolly:





This time as the hammer strikes the apex of the dent from above, and the dolly rests against the one from below, their offsetting positions will cause the resulting forces in the direction of the blue arrows, forcing the metal back into itself, or causing a shrink.


Seldom is the case where we have a one-sided dent as shown above. Typically with an off-dolly scenario in fixing a dent, you are using off dolly and working around the perimeter of the dent to bring things back where they were.

With the process shown earlier with the donut dolly, you basically are supporting the stretched metal from two points, so we can off-dolly with more effectiveness, as the forces we are now introducing with the hammer strike will be more concentrated, forcing the stretch into the hollow of the dolly. But lets back up a second and look at the forces at work when a dent forms.





As an outside force is applied to the door of your new car (blue arrow), the direct reaction is a stretching of the metal, causing it to cave in. But we also have an indirect reaction to this stretching as the panel "springs back" slightly and in many cases you'll now notice a slight bulge or high spot around the perimeter of the dent (yellow arrows) So in some cases, depending on how the panel reacts to these forces, effective dent removal may include working both sides of the panel. And anything we can do to assist with the shrinking process, like heat application, will speed up the process of dent removal that you would normally see with off dolly alone..