What are the techniques for applying auto body filler?
2 Answers
The techniques for applying auto body filler are: 1. Fill larger dents using a wider, harder spreader, focusing on leveling rather than achieving smoothness; 2. Primarily fill low concave areas with a thinner layer than the first step, using a hard spreader for flat surfaces and a rubber spreader for curved areas; 3. Fill pores left by the previous two steps, sandpaper marks, and smaller dents. Auto body filler is a viscous substance mainly composed of extender pigments, driers, and solvents. It is applied to surfaces already coated with primer to fill defects such as dents, weld seams, and scratches on car bodies and components. Through layers of application and sanding, a smooth and even surface is formed.
Applying body filler to cars may sound simple, but it's actually quite challenging in practice. I've been tinkering with this since college, and I believe the most crucial steps include several aspects: First, you must choose the right type of filler—ordinary polyester filler will do. Second, the mixing ratio must be accurate—1:50 hardener. Too little won't harden properly, and too much dries too quickly. Stir it slowly with a mixing stick. Next, the surface must be clean before application—wipe off grease with alcohol, apply a thin layer with your fingers, and avoid piling it too thick. Sand when the filler is semi-dry, starting with 80-grit coarse sandpaper and gradually moving to finer grits, finishing with 240-grit until it feels smooth. After drying, spray some water to check for evenness—redo any rough spots, or the paint job will look bad. Remember to wear a dust mask, as the particles are harmful to your lungs. The whole process takes about 30 minutes. Beginners, don't rush—be patient, and you'll get the hang of it after a few tries.
