Wet Sanding Exterior Paint: When And How To Do It Right

Wet sanding is a process that uses water or another liquid as lubrication to wash away grit particles and prevent surface scratches, creating a smooth, even finish. It is often used to improve the appearance of car paint, removing deep scratches, paint texture, and other defects. However, it is an aggressive method that should only be performed by experienced professionals as it can easily damage the paint if not done correctly. When performed correctly, wet sanding can create a flawless, mirror-like finish that shines.

Wet sanding can remove orange peel texture from car paint

Wet sanding is an effective way to remove the unwanted orange peel texture from your car's paint job. The orange peel effect is caused by the quick evaporation of thinner, incorrect spray gun setup, spraying at an angle, or applying excessive paint, resulting in a bumpy surface. Wet sanding knocks down the high spots, creating a more uniform and shiny finish.

To begin the process, wash your car to remove dirt, contaminants, and wax. Use a mixture of isopropyl alcohol and water for effective wax removal. Next, remove accessories like badges and stickers and tape up areas that won't be machine sanded, such as door handles and trim. It's crucial to choose the right grit for sanding, as a heavier grit can leave the paint too thin. Measuring the paint thickness with a paint gauge will help determine the appropriate grit. Most new cars have between 3 and 6 mils of paint.

For the sanding process, start with a lower grit sandpaper, such as 1000 or 1500, and gradually move up to a finer grit, like 2000. Use wet/dry sandpaper and keep it well-lubricated with water or a mixture of water and detergent. Always sand in a straight line, first horizontally and then vertically, to achieve a uniform finish. This process will take time and patience, as you refine the surface and remove the orange peel texture.

After sanding, use foam-backed discs of a higher grit, such as 2000, to further even out the paint and prepare it for the next step, which is compounding. This step involves using a rotary polisher to remove the haze left by sanding, resulting in a smooth surface. Finally, apply a protective coating to maintain the glossy finish.

Wet sanding to remove orange peel from car paint requires skill and precision. It is crucial to follow the steps correctly to avoid damaging your car's paint job.

It can also remove scratches from car paint

Wet sanding is a great way to remove scratches from car paint. It is a subtractive process, meaning that it removes paint. Therefore, it should only be used when there is still paint under the scratch. If the scratch is deeper than the paint level, wet sanding is not the solution.

Wet sanding is a multi-step process that starts with levelling the paint surrounding the scratch and ends with restoring the shine. The number of steps depends on the severity of the scratch. The goal of wet sanding is to smooth out the roughness of a shallow scratch. When a car's paint is scratched, it leaves tiny, rough divots. When light hits the uneven surface, it stands out because the light bounces back in all different directions compared to the unscratched surface. By wet sanding, you can smooth out the scratch and then buff it out so that it shines and blends back in with the surrounding paint.

Before wet sanding, it is important to clean the scratch and the surrounding area with an all-purpose cleaner and a microfiber towel. This ensures the area is contaminant-free, and you won't be scraping dirt back into the paint. You should also test whether the scratch is repairable by wet sanding. You can do this by spraying some water on the scratch. If the scratch disappears or fades, it means it is only in the clear coat of the paint and can be repaired. If the scratch is on a sharp edge or body line of the car, wet sanding is not recommended, as it can lead to removing too much paint too quickly and causing permanent damage.

If the scratch is repairable, you can start wet sanding. First, place painter's tape around the scratch, leaving about an inch on each side. Then, using a spray bottle filled with water, spray the area. Next, using sandpaper (usually starting with 3000 grit or higher), sand the paint across the scratch, not along its length. This will sand down the clear coat while also blending the scratch into the paint. Sand until the scratch is no longer visible, keeping the area lubricated with water.

After sanding, wipe down the area and remove the tape. If the scratch is still visible when fully dry but disappears when wet, you can move on to the next step of buffing. If the scratch is still visible when wet, repeat the sanding step, as the next stage of sanding will be less aggressive and aims to remove the sanding scratches caused by the previous grit.

Wet sanding can be a risky process, as it is easy to go too far and burn the paint. This happens when the scratch is so deep that there is no paint left under it, or you sand too much and remove the remaining paint layer. Therefore, it is important to be careful and know when and how to wet sand correctly.

It is important to use the right sandpaper for wet sanding

Wet sanding is a great way to improve the quality of a paint job. It can be used to remove contaminants, runs, overspray, and paint oxidation. It can also be used to remove the orange peel effect, improving the clarity of the paint.

When wet sanding, it is important to use the right sandpaper. The correct sandpaper will ensure the job is done effectively, without leaving unsightly grooves or causing damage to the surface. Sandpaper comes in different grit levels, ranging from coarse to fine. The grit level refers to the size of the abrasive particles, with lower grit numbers indicating larger grains and higher grit numbers indicating smaller grains. For wet sanding, you will likely use high-grit sandpaper, from 1000 grit to 3000 grit and above. This is because wet sanding is typically used as a finishing process, where you will use a light touch to refine the surface and achieve a smooth, lasting finish.

The type of sandpaper you choose will depend on the material you are sanding. For example, if you are sanding wood, you can use garnet sandpaper, but this will dull quickly compared to ceramic sandpaper. If you are sanding metal, aluminum oxide or silicon carbide sandpaper is a good choice as it will remove rust or old paint. For wet sanding final finish coats, silicon carbide sandpaper is available in extra-fine grits.

It is also important to consider the condition of the paint you are sanding. If the paint is in poor condition, you may need to start with 100-grit sandpaper, followed by a primer. If you are removing scratches or smoothing the surface, medium-grit sandpaper (60-100) is a good choice. For sanding between coats of paint, fine-grit sandpaper (120-220+) is recommended.

In addition to choosing the right sandpaper, it is also important to use a backing pad when wet sanding. This will help you achieve a uniform finish and prevent the sandpaper from folding back on itself.

Wet sanding is different from dry sanding

Wet sanding is a finishing process that requires specific waterproof sandpaper and is usually done by hand. It is used to refine the surface and achieve a smooth, lasting finish. The process involves using water or another lubricant, such as WD-40 or detergent, to reduce dust and minimise scratches on the surface. Compared to dry sanding, wet sanding uses higher-grit sandpaper, typically starting from 1000 grit to 3000 grit and above. It is often used for projects that require a very smooth finish, such as automotive painting or high-end furniture finishing.

On the other hand, dry sanding is a more aggressive approach that allows for quicker material removal. It is commonly used for initial rough sanding and shaping of the project. Dry sanding does not require any drying time, making it faster and more efficient than wet sanding. It can be performed by hand or with power tools, using small circles to remove material and minimise deep scratches. This method creates more dust and debris, and there is no additional lubricant required besides elbow grease. Dry sanding is suitable for materials that are sensitive to water, such as certain types of wood, metal, and plastic.

The main difference between wet and dry sanding lies in the use of water or another lubricant in the process. Wet sanding uses water to lubricate the sandpaper, resulting in a smoother finish with fewer scratches. It also helps to reduce dust production and prevent overheating of the sanding surface. In contrast, dry sanding relies solely on the abrasive action of the sandpaper without any lubrication.

When deciding between wet and dry sanding, consider the type of material, the desired finish, and the working environment. Wet sanding is ideal for achieving a high-quality finish, dust control, and working with heat-sensitive materials. On the other hand, dry sanding is preferred for rapid material removal, convenience, and working with water-sensitive materials.

Wet sanding is often used to finish a project

Wet sanding is achieved by using water alongside an abrasive pad or sandpaper. The water acts as a lubricant, reducing heat and friction during the sanding process. It also helps to prevent the sandpaper from getting clogged, prolonging its usability. This method is ideal for smoothing out imperfections, such as scratches and orange peel texture, and can be used on various surfaces, including wood, metal, and automotive paint.

When wet sanding, it is important to use the correct grit sandpaper for the specific surface and desired outcome. For example, when sanding a glossy surface, one would start with coarse-grit sandpaper and then move on to fine-grit sandpaper later. It is also crucial to keep the surface well-lubricated and to rinse away any sanding material when needed.

Additionally, wet sanding requires the use of a backing pad to achieve a uniform finish. This helps to prevent the sandpaper from folding back on itself and creates a smoother finish than using your hands alone. The process involves sanding in straight lines, first horizontally and then vertically, as opposed to the small circles used in dry sanding.

Wet sanding is a highly effective method for achieving a professional-grade finish. It is a meticulous process that requires patience and the right tools, but the results are well worth the effort.

Frequently asked questions