How Many Bottles of Undercoating Are Suitable?
3 Answers
This depends on the thickness of the application, but generally, four to five bottles are sufficient. Introduction to Undercoating: The technical term for automotive undercoating is "UNDERCOATING," a high-tech adhesive rubber asphalt coating used for anti-impact, anti-rust, and sound insulation on the vehicle's underbody. Functions of Undercoating: It is non-toxic, provides high coverage, and has strong adhesion. It can be sprayed on exposed areas such as the vehicle's underbody, wheel hubs, fuel tank, lower body panels, and trunk. After quick drying, it forms a durable elastic protective layer that prevents damage from flying stones and gravel, protects against moisture, acid rain, and salt corrosion on the underbody metal, prevents rusting and corrosion, and ensures driving safety for the vehicle owner.
I've applied undercoating many times, and from experience, the number of cans needed mainly depends on the car's size. My compact hatchback only took two cans to fully cover the undercarriage, which felt quite economical. Later, when I switched to a mid-size SUV, it required a full four cans because of the larger undercarriage area. I've also noticed that the type of coating affects the quantity - water-based formulas are lighter, allowing one can to cover more area, while oil-based ones are more durable but need thicker application (2-3mm works best). Applying too little provides inadequate protection against rust and noise, while over-application wastes money and may cause bubbling. When purchasing automotive coating products, check the label - each can usually indicates its coverage area in square meters. Thoroughly cleaning the undercarriage is crucial; dust and rust must be removed before application, or the effectiveness will be compromised. I always prefer consulting professional shops - they can quickly estimate the required amount. Considering that undercoating is a one-time investment protecting your vehicle for years, it's worth spending extra time to understand the process.
As someone who has worked in car factories for years, I recommend scientifically calculating the number of cans for undercoating. For small cars like the Polo, two 500ml cans of undercoating fluid are usually enough, covering 6-8 square meters of the underbody. For mid-sized sedans like the Camry, three cans are needed. For large SUVs or pickup trucks, four or more cans are required. The standard spraying thickness should be controlled at 2-3 mm—too thin and the rust protection is poor, too thick and it may crack or waste material. Always remove rust and oil before spraying, and ensure the working environment is dry and ventilated. The coverage per can is usually indicated on the product packaging, but it's best to refer to the original vehicle manual for precise measurements. Skimping on cans is unsafe, especially on salted roads in northern regions, where extra spraying is needed for corrosion protection. It's more reliable to have a professional shop inspect the underbody wear before deciding on the number of cans—after all, undercoating is a long-term investment in protecting the underbody and extending the vehicle's lifespan.
