Should the Original Paint Be Sanded Off Before Repainting?
2 Answers
When repainting the entire vehicle, it is not necessary to sand off the original paint; simply pay attention to color matching for the original painted areas. Key considerations for repainting: Color Matching: During paint mixing, special attention must be paid to color differences. Protective measures should be taken, covering all non-painted areas with newspaper or other masking materials. Also, pay attention to spray gun pressure and working environment conditions. Baking Time: The spray path should maintain perpendicular alignment with the workpiece surface. The distance between the spray gun and the surface typically ranges from 15 to 30cm, adjusted according to the surface angle. For wetter, darker, and thicker coatings, reduce the distance; for drier, lighter, and thinner coatings, increase the distance. Spray Angle: The spray gun should maintain a right angle to the surface and move parallel during automotive painting. The gun movement speed should be consistently maintained between 30 to 60cm/s. Tilting the gun or using arcing motions with variable speeds will result in uneven paint thickness, causing streaks and blotches. Movement speeds below 30cm/s may lead to paint runs.
As someone who frequently does DIY painting, I've found that whether to remove the original paint depends on the situation. If the original paint is still smooth and crack-free, simply sanding the surface to help the new paint adhere is sufficient—it saves both effort and time. However, if the original paint is already bubbling or damaged, it must be completely removed; otherwise, the new paint will easily peel off. I remember the last time I repainted an old car, I didn't properly sand the original paint, and within six months, the new paint cracked, costing me more to redo it. Here's a little tip: use medium-fine sandpaper to sand evenly, avoiding excessive force that could damage the underlying layer. After applying the new paint, it's best to let it dry for 24 hours without touching it to ensure it sets firmly. These insights come from multiple experiences and can help you avoid common pitfalls.
