Which method is commonly used for dent removal in metal surfaces?

Using heat and cooling techniques is an effective method for dent removal in metal surfaces because it takes advantage of the physical properties of metals. When heat is applied to the dented area, it causes the metal to expand. Subsequently, cooling the area rapidly, often with a compressed air method or other cooling substances, causes the metal to contract. This expansion and contraction can help the metal return to its original shape, effectively removing the dent.

This technique is especially useful for shallow dents where the integrity of the metal hasn't been compromised significantly. It is a preferred method because it generally does not require any repainting or additional finishing work if done correctly, maintaining the original surface quality of the vehicle.

In contrast, painting over a dent does not actually repair the damage; it merely masks it, which could lead to further issues down the line. Filling with body filler is a common practice for larger, deeper dents but is more of a repair method once the dent cannot be popped out; it requires sanding and painting afterwards. Applying pressure from the underside can be effective in certain situations, but it is not as universally applicable as heat and cooling techniques for metal surfaces.