Undercoat rust refers to the appearance of tiny speckled rust spots on the surface of the paint film shortly after application. At this time, it should be repaired as soon as possible, because the rusted part will be slowly oxidized and corroded, resulting in a larger rusted area. So what is the reason for the formation of rust?
1. The surface treatment of the car body before painting is not cleaned thoroughly, and there are still problems such as corrosion, moisture, water drops, sweat marks, etc., or the surface is not sprayed in time after the surface treatment.
2. Defects such as cracks and pinholes in the paint layer allow moisture to penetrate from the surface paint layer to the bottom car paint layer and metal substrate, resulting in rust later.
3. The auto paint itself has poor anti-corrosion performance, and the paint film is damaged by sand and stones to erode the metal layer, which will also slowly cause the bottom to rust.
Correction method:
A. Remove the rusted automotive paint layer, polish the rust spots until the substrate appears metallic luster, clean the surface of the metal substrate, avoid direct touch the treated metal surface with your hands after drying, and re-spray as soon as possible, because bare body steel plates are prone to rust if exposed to the air for too long.
B. When replacing accessories such as body moldings, be careful not to damage the paint layer, and avoid contact with different metals, because the electrolysis caused by such contact may reduce the adhesion between the paint surface and the bottom layer.
