Will the exposed white primer on a black car rust?

[Ethan]

Black car exposed white primer will not rust. Knowledge about car rust is as follows; Introduction: Rust is a chemical reaction that occurs when iron is left for a long time. Iron is prone to rusting, not only due to its active chemical properties but also greatly influenced by external conditions. Moisture is one of the substances that make iron prone to rust. Principle: Water alone does not cause iron to rust. Only when oxygen in the air dissolves in water, and the oxygen reacts with iron in a watery environment, does it produce a substance called iron oxide, which is rust. Rust is a reddish-brown substance, not as hard as iron, and easily flakes off. When a piece of iron completely rusts, its volume can expand up to 8 times. If rust is not removed, this spongy rust is particularly prone to absorbing moisture, causing the iron to deteriorate even faster.

[ZoeLee]

My black car got scratched by a tree branch recently, revealing the white primer underneath, and I was really worried it might rust and affect the whole car. After consulting a car-savvy friend, I learned that the primer itself is designed to be rust-proof, especially in newer cars where the underlayer is coated with anti-corrosion materials. If it's just exposed without cracking, it's unlikely to rust in the short term, say within a few months. However, the issue is that primer isn't as wear-resistant as the topcoat. Over time or when exposed to rain or salt, the primer might wear away, exposing the metal beneath, which can then oxidize and rust. Moreover, rust spots can spread over time, making repairs more troublesome and costly. So, my advice is to clean the exposed area as soon as you notice it and apply some rust-proof spray for temporary protection. If the scratch is deep, it's best to get it professionally repainted to prevent long-term corrosion and extend the car's lifespan. Regularly washing and inspecting your car's exterior is key to prevention—don't let small issues escalate.

[SanReed]

After driving for a long time, you'll realize that the white primer exposed when the car paint peels off is actually part of the rust-proof layer, designed to block moisture and air. For example, my old car had a similar situation—if the primer remains intact, the chance of rust is low. But don’t assume it’s completely safe—the primer is thin and can wear down over time due to wind and sun exposure. Once the bare metal is exposed, rust begins, especially faster in humid cities or coastal areas. I must remind you to gently feel the primer during inspection to check if it’s smooth and intact. If there are cracks or flakes, act quickly—use a DIY touch-up paint pen to cover it or seek professional help. Ignoring it will not only make the rust spread and look unsightly but may also compromise structural safety. Adding a car cover can provide an extra layer of protection, saving you both hassle and money.

[Stacey]

With decades of driving experience, I've seen many cases where the car paint chipped off, exposing the primer. That white primer usually doesn't rust easily because anti-rust components are added during production. But if neglected, once the primer ages or gets damaged by stones, rainwater can seep into the metal, and rust will definitely occur. My neighbor's car is a perfect example—a small scratch was left untreated, and half a year later, it rusted into a big hole, costing a fortune to repair. So my advice is: as soon as you see exposed primer, take action immediately—clean the surface and spray some simple rust inhibitor. If the primer is intact, don't delay. It's not worth turning a small issue into a big one.