What are the methods for dealing with cracked car paint?
4 Answers
Methods for dealing with cracked car paint are: 1. Sand the cracked paint area until a complete and smooth surface is exposed, then repaint; 2. Repaint the affected area; 3. Polish and buff to remove the oxidized layer of paint, and regularly wax to maintain the paint for up to 5 years. Car paint maintenance methods include: 1. During vehicle use, promptly remove dust from the car body before, during, and after driving to minimize the adsorption of dust by static electricity on the car body; 2. Rinse the car promptly after rain; 3. Wash the car when the engine is cooled down, and avoid washing the vehicle under direct sunlight or high temperatures to prevent the cleaning agent from drying and leaving marks.
Last time, many fine cracks appeared on my car's hood, and I handled it myself. I thoroughly cleaned the cracked areas with a clay bar, then lightly sanded the surface with wet water sandpaper. After smoothing out the cracks, I wiped them dry with a towel and applied a small amount of touch-up paint evenly, letting it cure for half an hour. Finally, I polished it in circular motions with polishing wax, which basically covered the small cracks. The key is not to sand too hard to avoid damaging the color paint, and to apply the touch-up paint in small amounts multiple times for a seamless finish. Avoid long-term exposure to sunlight when parking, and waxing monthly can effectively prevent new cracks. If the cracks reach the primer, it's best to visit a professional paint shop for repair to prevent rust and further complications.
Repairing cracks in a body shop typically involves three steps: first, clean and degrease the surface, then use 2000-grit sandpaper with water to remove the oxidized layer; next, fill in any depressions, applying epoxy resin for deep cracks; finally, respray the entire area with clear coat. Actually, a polisher can only address superficial scratches on the paint surface—deep cracks require sanding down to the metal layer before respraying. Keep the spray gun 20 cm away from the surface and move at a steady speed, with the baking room temperature ideally set at 60°C for the most durable finish. In my experience, cracks most commonly appear on rooftops and hoods, usually after five years as the paint begins to age, especially in areas exposed to intense sunlight.
I pay the most attention to the condition of my car's paint during maintenance. When I notice fine cracks, I first use a scratch wax containing abrasive particles for manual polishing, which can usually remove minor scratches. For more noticeable cracks, I take the car to an auto repair shop for mirror-finish treatment: they machine-polish off about 0.1 mm of the clear coat and then apply glaze. However, severe hairline cracks indicate overall aging of the paint surface, and partial repairs may leave visible seams—repainting the entire panel yields better results. For prevention, I recommend applying fluorinated car wax every quarter, avoiding strong alkaline cleaners when washing the car, and promptly removing tree sap or bird droppings. If parking outdoors for more than six months, it's best to use a car cover, as UV rays are the main cause of cracking.
