How to Remove Old Paint?
4 Answers
Methods for removing old paint from cars include sandblasting, manual removal, mechanical removal, chemical removal, electric sanding, and flame scraping. Among these, manual removal, mechanical removal, and chemical removal are more commonly used. More details are as follows: 1. Chemical removal involves using paint strippers to eliminate old paint films. Commonly used strippers in the past were T-1 and T-2. T-1 stripper is a milky white paste-like liquid composed of ketones, alcohols, benzene, ester solvents, and an appropriate amount of paraffin. It is mainly used to remove old paint films of oil-based paints, ester gum paints, and phenolic paints. T-2 stripper is a mixture of ketones, alcohols, esters, and benzene solvents, with stronger paint film swelling ability and faster removal speed than T-1. It is primarily used for removing old paint films of oil-based paints, alkyd paints, and nitrocellulose paints. 2. Manual removal is a common method in painting work and the only method for partially removing old paint films. It mainly relies on tools like scrapers, knives, wire brushes, and sandpaper to remove old paint from the surface of car body components. This method is simple but labor-intensive and inefficient. 3. Mechanical removal uses electric or pneumatic tools, such as wire wheels, wire sanders, and dry/wet sandpaper sanders, to replace manual scraping and sanding. This method not only improves efficiency but also reduces labor intensity, making it widely used in the car body repair industry.
I find the most reliable method is using professional paint remover. The operation is quite straightforward. First, clean the surface dust with a steel wire brush, then use a brush to evenly apply the paint remover over the old paint, making sure to wear gloves and goggles. Wait for about ten minutes until the paint bubbles and softens, then scrape it off in one direction using a scraper or putty knife. For hard-to-reach corners, use a small scraper to clean slowly. After finishing, remember to wash off any residual chemicals with a neutral detergent, as they can corrode the new paint. Finally, it's essential to sand the surface smooth with fine sandpaper—this step must not be skipped, or the new paint may peel off. Ensure good ventilation throughout the process, as the chemical fumes are quite strong.
For DIY projects, I prefer sandpaper grinding—it's cost-effective and safe. Prepare sandpapers of different grits, starting with 120-grit for coarse grinding, then switch to 240-grit for fine grinding. Remember to use a sanding block or holder to save effort; hand-sanding alone can blister your thumb webbing. Pay special attention to corners and curved surfaces, adjusting your posture frequently for even sanding. Stop when the base material is visible and the surface is uniformly rough. After sanding, vacuum the dust thoroughly and wipe with a damp cloth. However, this method is labor-intensive and not recommended for large areas. Be cautious not to over-sand metal parts. It’s ideal for furniture refinishing, preserving some vintage character.
Using a heat gun to remove paint is quite interesting, like giving the car a haircut. Set the heat gun to around 300 degrees Celsius and move it back and forth about 15 cm away from the paint surface. When the paint softens and wrinkles, use a scraper to peel it off, similar to scaling a fish. Be careful not to use it on plastic parts, as high temperatures can cause deformation. Metal parts are most suitable, but temperature control is crucial to avoid discoloration from overheating. Remove any remaining thin paint layers with steel wool after scraping. This method is fast but requires protective gear, as molten paint splatters can be painful if they hit your skin. It's especially handy for delicate parts like door handles, allowing you to reach every nook and cranny.
