Basic Panel Beating
Panel beating is the art of shaping the metal back to where it is smooth and level again. Learning how to be a panel beater is essential. It is the area in auto body work that requires the most skill and technique. The ability to direct the blows on the damaged area, along with how much force to exert, separates "the men from the boys," the amateur from the professional.
Practice is the key to becoming knowledgeable and proficient so do not attempt a large job right away; better to begin panel beating by practicing on a piece of scrap metal.
It is important to know a little about the dynamics of how the impact on the metal produces damage in the first place. When force from an accident impacts sheet metal, it produces an area of direct damage at the point of contact. The impact's indirect contact affects a wider area, leaving an array of buckles or "V" channels on the surface of the metal. These ridges appear hard or rigid. Also observe the direction of the force that caused the damage. This will be important because you are going to be repairing the damage exactly opposite of how it occurred. In other words, you will beat out the indirect damage first, then the direct damage.
Here is how to handle and apply tools. Hold the beater loosely in your hand. Allow the shaft to rest against the base of the thumb. Wrap your fingers loosely around the shaft. As you close the fingers to grasp the shaft, the head of the beater moves forward. Use this movement when working underneath surfaces, when both beater and the work surface may not be visible. Added wrist action will help you become more versatile. Heavier blows for larger areas will involve your elbow and shoulder. Strength and ability comes with practice. Do not grip the beater shaft tightly because this can cause fatigue in your arm muscles when working for long periods of time. Tip: at first it may be difficult to aim the beater correctly so that it hits the dolly below squarely. Practice.
Before you begin actually beating a damaged panel, make sure that you remove any underseal or other foreign material from underneath the metal. You can usually remove any under coatings with a putty knife or scraper. It may help to heat the material slightly with a torch first. Make sure the outside of the metal is free of dust, dirt, oil and grime by cleaning it with mild soap and water. Remove tar and asphalt with a rag and some solvent.
Using your beater and a dolly or spoon, first unfold the "V" channels, valleys and buckles on the damaged area. Then move on to the areas of more direct impact. Place the dolly below the panel and tap the top surface with the beater. You will find the high surfaces by feeling the beater's rebound. Be as gentle as possible, trying not to further stretch the metal and bring it up to near their original position and contour.