
No, if there is no damage to the body, just dull the paint surface. Here is some related information about car spray painting: 1. Purpose of Car Spray Painting: Car spray painting is to apply a layer of paint on the car's surface to achieve the effect of protecting the car. 2. Types of Car Paint: Car paint is divided into ordinary paint, metallic paint, pearl paint, etc. 3. Precautions for Car Spray Painting: Before spray painting the car, first treat some areas that are difficult to spray, such as the engine hood, trunk, door edges, etc. Spray these difficult areas first.

In all my years of driving, I've learned that sanding off the original paint is absolutely essential when applying new paint—otherwise, the new coat simply won't adhere properly. Last time I tried spot-painting without sanding, the finish started peeling within days, looking as unsightly as aged skin. The reason is straightforward: the original paint accumulates dirt, oxidation, or micro-scratches, and if not thoroughly sanded, the new paint will bubble, appear uneven, or become prone to water seepage and rust. For sanding, I typically use 200 to 400 grit sandpaper, meticulously treating the surface to ensure the new paint bonds securely. If you go to a professional shop, they’ll first sand the entire area comprehensively to guarantee a smooth, seamless finish—this isn’t just for aesthetics but also to prevent corrosion from spreading. So, don’t skip this step—it’ll save you repair costs down the road.

In my experience with car DIY, I've found that sanding off the original paint is a crucial step before repainting. Imagine spraying new paint directly over the old—residual grease or oxides on the original paint surface can interfere with adhesion, causing the new coating to bubble or peel within days. I usually use sandpaper or a grinder to sand down the body area, focusing on removing old paint and impurities to ensure a slightly rough surface for better paint adhesion. For small local repairs, you can just sand around the damaged area to avoid redoing the entire car. However, for major projects, a full sanding is necessary because aged original paint becomes brittle, and new paint applied over it may develop cracks. Remember, adding a primer before painting is even better—it ensures more uniform color, prevents rust, and saves both money and effort.

I believe that to maintain a car's perfect appearance, the original paint must be sanded off before applying new paint. The original paint may have dust, tiny cracks, or signs of aging. If not thoroughly removed, the new paint will appear uneven and patchy, affecting the overall aesthetics. I've seen a friend skip this step, and the new paint quickly faded or wrinkled, looking as unattractive as makeup without primer. During the process, I prefer starting with localized sanding to ensure a clean surface free of residue, allowing the new paint to be smooth and long-lasting. Additionally, this prevents oxidation issues from accumulating underneath, reducing future repair hassles. Professional detailers also recommend this step to ensure the car stays shiny for the long term.

My experience is that you must sand off the original car paint before repainting. At first, I didn't know better and sprayed a new color without sanding, only to find the paint cracking and peeling within weeks, costing me a lot of money to fix. The reason is that oil or dirt on the original paint surface can prevent the new paint from adhering properly, and sanding removes these hidden risks. For the specific process, I recommend using medium-coarse sandpaper to evenly sand the relevant parts of the entire car, making the surface slightly rough to help the new coat adhere better. If you're just fixing small scratches, you can save time by sanding only a small localized area. However, no matter what, cleaning and sanding are essential steps—otherwise, the new paint may bubble or corrode the car's metal body, affecting the vehicle's lifespan.


