Does a full-body paint job require removing the original paint?

[LilaFitz]

When repainting a car, the original paint needs to be sanded off for the following reasons: 1. Paint thickness: Repainting will increase the thickness of the paint layer; 2. Paint application area: The newly painted area will be higher than the original paint surface; 3. Peeling: The new paint may separate and peel after blending with the old paint; 4. New paint vulnerability: The new paint is prone to peeling during car washes; 5. Color mismatch: There may be color discrepancies. Post-painting precautions include: 1. Wax-stripping detergents: At car washes, ensure the staff does not use wax-stripping detergents to avoid damaging the paint; 2. Daily rinsing: Vehicles driven in coastal or heavily polluted areas should be rinsed daily; 3. Washing: Use clean, soft cloths or sponges to wash the vehicle, avoiding materials that might contain metal shavings or sand particles. Do not use dry cloths, towels, or sponges to prevent scratches.

[DeAlexander]

I once tried doing a full car paint job with a friend and found it quite interesting, but we got lazy and didn't fully remove the original paint—just gave it a light sanding. Within a few months, the new paint started bubbling and peeling, making the car look even worse, and we had to spend a lot of money to get it professionally redone. It turns out, the principle is similar to painting a wall: if there's grease or old paint residue, the new paint won't adhere properly. On a car, old paint might have rust, uneven spots, or loose primer, and skipping removal can lead to delamination and peeling. The proper approach is to thoroughly sand the surface with sandpaper or a sandblaster, or even strip the old paint entirely, ensuring the metal is smooth and clean. Now, whenever I see someone considering a DIY paint job, I always warn them: never skip this step, or you'll pay more in the end.

[RowanRose]

I've been driving for over twenty years and enjoy learning some car repair skills in my spare time, so I often observe the painting process. For a full car repaint, the original paint must be removed or at least heavily sanded down. Otherwise, the new paint layer won't adhere properly and is prone to peeling or bubbling. This isn't just about aesthetics - if there's rust beneath the old paint, covering it with new paint will actually accelerate rust spread, compromising the structural safety of the vehicle. Moreover, many modern cars use contemporary paint materials that have poor compatibility with older paints from decades ago. Painting directly over old paint might even alter the color tone. I recommend getting a professional assessment first, using machines to sand down to bare metal or preserve any usable base layers, avoiding DIY mistakes. While regular maintenance can prevent many minor issues, paint jobs are best left to the experts.

[LaKyle]

As a car enthusiast, I have some knowledge about the painting process. A full-body repaint absolutely requires treating the original paint, otherwise the new paint won't adhere properly. Simply put, you need to sand or chemically treat the old surface first, removing rust and loose parts to ensure it's clean and smooth. Without this step, the new paint may crack or peel after drying, which becomes more noticeable when driving in rain or on bumpy roads. I recommend assessing the vehicle's condition - some cars with well-preserved original paint in certain areas can retain small portions of the base layer, but large-scale repainting requires thorough preparation. Relevant factors include paint type and climate effects, with rust removal being particularly crucial in humid southern regions. In short, don't cut corners - it's safest to consult professional shops for advice.