Before application, the vehicle must be lifted, and the chassis thoroughly cleaned with a high-pressure water gun and specialized cleaning agent to remove oil and rust. Then, use an air gun to dry the surface. Afterward, cover components that do not require painting, such as the exhaust pipe, engine oil pan, transmission, brake discs, drive shaft, and sensors, with masking materials such as masking paper and aluminum foil tape. During spraying, apply in layers. First, spray a zinc-based anti-rust primer. After it cures, apply the main coating in 2-3 coats, allowing approximately 20 minutes between each coat to ensure drying. The total thickness should be controlled at 2-4 mm. Maintain a 15-30 cm distance between the spray gun and the chassis, moving at a constant speed to ensure even coverage, paying particular attention to chassis edges and wheel arches, which are prone to impact. The application environment should be a dust-free, well-ventilated area with a temperature of 15-30 degrees Celsius and humidity below 60%.
After spraying, remove the masking materials and allow the vehicle to stand still to allow the coating to dry. In sunny weather, the coating typically takes 2-4 hours to surface dry, but complete drying and curing takes approximately 24-48 hours; some products recommend waiting up to 3 days. During this period, the vehicle should avoid driving, especially preventing the chassis from coming into contact with water or driving on bumpy roads, as this can affect the coating's adhesion and curing.
To ensure long-lasting protection, it is recommended that vehicle owners have a visual inspection of the chassis every 20,000 kilometers or every year. The inspection should focus on checking for any peeling, flaking, cracking, or edge lifting of the undercoating, as well as new rust spots on critical areas of the chassis.
If the inspection reveals small areas of localized damage or peeling of the undercoating, targeted touch-up repairs can be performed using a portable spray gun. If there is extensive coating peeling or a significant reduction in protective effectiveness, the vehicle must be taken to a professional shop to have the old coating sanded down to expose the metal substrate, and then cleaned, masked, and repainted according to standard procedures.
Vehicle owners or professionals can assess the protective effect of the undercoating using various methods. This includes visually inspecting the coating for uniformity, peeling, flaking, or cracking; touching the surface to feel for smoothness; gently tapping the coating with a small tool-a clear, crisp sound usually indicates strong adhesion and good protective effect; and rinsing the chassis with water to check if the water flows off quickly without accumulating, thus verifying its waterproof seal.
