Causes of Corrosion at the Bottom of the Paint Film and Correction Methods

Causes of Corrosion at the Bottom of the Paint Film and Correction Methods

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 and 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 clean, and if there are still problems such as corrosion, moisture, water droplets, sweat marks, etc., paint directly, or do not spray in time after surface treatment.

2. There are defects such as cracks and pinholes in the paint layer, which allow moisture to penetrate from the surface paint layer to the bottom paint layer and metal substrate, resulting in rust behind.

3. The 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 paint layer on the rusted part, polish the rust spots until the substrate has a metallic luster, clean the surface of the metal substrate, avoid direct contact with the treated metal surface with your hands after drying, and re-spray as soon as possible. Bare and leaky 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 tear the paint layer or reduce the adhesion between the paint surface and the bottom layer.