Should touch-up painting be done in a small or large area?

[EmmanuelFitz]

Touch-up painting should only cover the necessary area. Below is the process for touch-up painting: 1. Determine the repair area: Carefully inspect the damaged area. If the damage exceeds one-third of the component, a blending repair method should be used. Blending repair involves applying clear coat over the entire component while transitioning the base coat from the damaged area to the original paint. This maximizes the retention of the original paint and avoids color mismatch issues. If the damage exceeds one-third, the processes of sanding, priming, base coat, clear coat, and blending will cover more than two-thirds of the component, leaving little untouched area and making the repair less meaningful. 2. Surface preparation: Mix an appropriate amount of body filler and hardener based on the size of the damage (ratio: 100 parts body filler to 2-4 parts hardener, adjusted according to temperature). Fill the dent or scratch firmly, then use a scraper at a 45-degree angle to level the surface slightly above the component. Use an iodine-tungsten lamp to speed up drying. Once dry, sand with P320 grit sandpaper to level, then with P800 grit for smoothness before applying primer. 3. Masking and degreasing: Use an air gun to remove moisture and dust from component gaps, then carefully mask non-painted areas with masking paper. Wipe the painted area with a paper towel dipped in degreaser, followed by a tack cloth with an air gun for thorough cleaning before applying the base coat. 4. Base coat application: Dilute the mixed base coat thoroughly (1:1 ratio with thinner) and filter it. During spraying, control the spray area, set the air pressure to 2KPa, and use a dry spray technique. After each coat, wipe with a tack cloth. Gradually transition from covering the primer outward until no color difference is visible.

[Suzanne]

Oh, I usually handle automotive paint repairs and need to decide between spot repair or full panel repainting based on the damage condition. Spot repair is suitable for minor scratches or light scuffs, like a small dot on the car door – just use a touch-up pen for local application. It's convenient and cost-effective, with virtually no part removal required. However, full panel repainting is necessary for extensive damage, such as a completely scratched rear bumper or color mismatch due to paint aging. In such cases, the entire panel must be removed for spraying to prevent noticeable color differences affecting aesthetics, since paint codes vary between old and new layers. A full treatment ensures overall harmony. I recommend car owners first assess the damage depth – handle minor issues themselves, but seek professional shops for major problems to avoid cutting corners and future troubles.

[LolaFitz]

From my driving experience, minor paint scratches are quite normal, and small touch-ups are the most common solution. For example, a small scratch near the dashboard can be easily fixed with a touch-up pen, costing just a few dozen bucks—quick and hassle-free. However, for major damage, like a deep scratch on the hood, a full repaint is necessary to prevent rust or bubbling. This costs a bit more, usually around one to two thousand, but it protects the car's value in the long run. I've found that location matters too—small touch-ups work for corners or less visible spots, but for prominent areas, a full repair is more reassuring. Also, if the paint has aging cracks, small touch-ups may not last, and a full refinish is needed for durability.

[OThomas]

As a young car enthusiast, I always pursue the perfect appearance of my car. Small-area touch-ups are quick and cheap, ideal for fixing minor scratches when on a tight budget, but the risk is uneven color that can look glaring. Large-area repainting focuses more on the overall effect, such as replacing parts or full repainting for major damage, ensuring the color blends in seamlessly for a significant aesthetic boost. Although it costs more, I'd rather spend extra to guarantee my car looks stunning on the road. Metal parts also need consideration—small touch-ups may not prevent rust adequately, potentially leading to bigger issues. In short, small repairs are practical and convenient, while major repairs are reliable but time-consuming. I recommend regular car washes and inspections to detect and address issues early.