Wetsanding isn’t very difficult in the steps you need to take. It’s the technique that makes the difference. When mastered, wetsanding can give very good results, but it is also very risky and should be done with great care.
The steps for wetsanding
When wetsanding, you want to remember a few basic rules: don’t use to much pressure, don’t try to go as fast as possible, and keep the lube coming.
The steps themselves aren’t very difficult.
- Put your wetsanding papers in a bowl with clean water. Leave them to soak for a few hours before using them
- Wash, clay and decontaminate the surface before starting
- Use your paint depth gauge to see how much paint you have to work with
- Make sure the surface is clean enough for polishing
- Tape of surrounding areas and edges that you don’t want to sand
- Make sure you have plenty of water and/or lube to use as a lube
- Take your least rough wetsanding paper (often 3000 grit or higher) out of the bowl with water
- Wrap the wetsanding paper around a block of foam or similar
- Wet the surface with plenty of water
- Rub the wetsanding paper softly over the surface, with very little pressure
- Make long strokes of at least 10 inches, if possible more
- Look at how it affects the paintwork, and see if this is good enough
- Is the wetsanding paper rough enough, continue using it. Not rough enough, go up 1 step
- Rinse away the milky water/paint-mixture from the surface and wipe dry with a microfiber towel to check the result
- Rinse the wetsanding paper clean, and continue wetsanding
- It is totally dependent on the grit and the surface how many passes you have to make
- Continue sanding, rinsing and adding water till you’re happy with the result
- When done, use a cutting polish to bring back the shine. Work your way up from cutting to polishing and finally finishing
Wetsanding isn’t easy to master. You need to feel whats happening, and understand what you are feeling. Without this experience it is very difficult to judge what you need to do. Applying more pressure might be needed, but you need to know for sure. Although it is difficult to put this experience in words, this list might help you to know what things to start with.
- Always start with as little pressure as possible, and see how that goes and feels
- Always use enough water to rinse the sanding paper and the surface
- Keep the wetsanding paper wet at all times
- Start out with the least rough sanding paper
- Always try to apply even pressure while sanding (a block of hard foam might help)
- When judging the result, rinse with plenty of water and wipe dry
- When wetsanding, the surface will show complete wetting and hardly any sheeting
- It is important to keep your sanding papers wet
- Try to prevent sanding to much on corners, the paint is often more thin here
- When sanding headlights, look carefully at how evenly matte the surface is becoming
- Don’t try to rush it, this job takes time but the results are worth it. Rushing it will not improve the result
Although you can read a lot on the subject, it is a job you need to get a feeling for. The feeling for sanding is difficult to master. Some go to a professional detailer for special courses on wet sanding.