Introduction: How to Wet Sand and Polish Paint
Video tutorial on how to wet sand and polish paint. I originally released a wet sanding tutorial video back in 2013, so this is my updated version covering commonly asked questions and showing a more detailing process along with what to expect during each stage.
- 1000 grit wet/dry sandpaper
- 1500 grit wet/dry sandpaper
- 2000 grit wet/dry sandpaper
- bucket of water with carwash soap
- access to a hose
- polishing compound
- soft clothes
- microfiber clothes
- backing pads (foam block, rubber pad)
First I will be starting out with single stage paint and in the second part of the video will be two stage paint. Wet sanding will remove orange peal, improving the clarity and imagine in the paint. It will also help remove foreign contaminants which maybe on the surface in the paint along with runs, overspray, and even paint oxidization. It can be used on both single and two stage paints. Single stage paints is a form of paint applied which is both the color and finish coat and will dry with a shiny finish. Two stage paints require a base coat which is a color and finally a clear coat which provides the final shine and protection to the base color. Wet sanding is a great way to improve a good paint job and can even be used to help improve the quality of a poorly laid paid layer.
Starting first with this Ranger that I repaired the cab corner on. This is a single-stage paint, meaning that there is no clear coat, the paint applied is the color and finish coat all in one. If you are planning on wet sanding a current project that painting, make sure you have enough paint material to work with. Otherwise, you can sand or burn through the paint layer, exposing the primer or causing thing areas which may create a ghosting effect. The area would need to be repainted in order to repair this mistake.
After painting something, I typically like to wait at least a week so the paint is cured, however, this can depend on the paint thickness and your climate. The paint needs to be hard so the sanding won’t cause damage or imperfections in the final finish.
Using a bucket of water, soap can be mixed in to help aid in the sanding process. While the soap isn’t mandatory, it does help lubricate the surface, providing a cleaner material takedown. I would only recommend using a carwash soap as it won’t dry out any rubbers on the vehicle.
With the sandpaper, backing pads can be used, this can be anything from a flexible rubber pad to a foam block. Backing pads should be used across larger flat surfaces to provide even pressure so you don’t create waves with your fingers.
Courser grits can be used, typically I like to start with 1000 grit. Wet-Dry compatible sandpaper can only be used here, other types of sandpaper will fall apart when exposed to water. Ensure the surface is clean and wet, always pre-soak the sandpaper and then continue to sand the surface.
Evenly go over the surface removing any orange peel. Always keep the surface well lubricated and rinse away any sanding material when needed. Considering this was a blended area, overspray or heavy orange peel can be present at the fade areas, especially since this was done with spray paint. You can lightly go over this area.
The high areas have been touched with the sandpaper, while the low areas are still shiny. Around body lines or edges, this can be done by hand, but be very careful when using your hand. If you are sanding close to trim pieces, these can be covered up with tape as a form of protection.
Once done with the 1000 grit sandpaper, almost all the orange peel should have been removed. There’s no need to dry the surface, but it does help to see how the surface looks and if you missed any spots. There should be a uniform finish, most of the orange peel should have been removed.
Rinse the area, removing any sanding material and move up to 1500 grit sandpaper, again using the same process. Always pre-soak the sandpaper, ensure the area is wet and work evenly across the surface. With a single-stage paint, you’ll notice the color of the paint in the sanding residue which is normal. If this was a two-stage paint, you would only be sanding the clear coat and the water will only turn milky. If you are getting color in a two-stage paint, that means you sanding through the clear coat and have damaged the finish.
Moving onto 2000 grit, using the same process, at this point, all the orange peel should have been removed and now you’re only left with preparing the paint for polishing, removing those coarse sanding marks. Work evenly over the surface just like before, keep the area well lubricated and rinse sanding material as needed. It’s not necessary to change the bucket of water when switching sanding grits, just make sure the bucket is quite full so any sediment from sanding has a greater chance settling to the bottom.
Once the wet sanding process is done, here is what I’m left with. Darker colored paints have a higher risk of showing imperfections so it does take more time to create a flawless surface. But with that being said, those imperfections will still exist on lighter colors, they’re just harder to see. A 3000 grit can be used here, but I finish with a little extra patience and time, a polishing compound can still achieve an excellent shine.
Using a polishing compound, here I’m using Meguiars Ultimate Compound. Depending on which polish is used, companies will typically have a list as to what the compound is intended for or a grit rating. This can be done by hand or with a machine polisher. Being that this is fresh paint, polishing by hand would be a safe choice and this isn’t a large area either.
You can use a buffing pad or I typically stick with soft clothes. Apply the polish to the cloth, it can be dabbed around the surface, then work it into the surface. It’s normally recommended not to work in circular patterns, if you pick up any dirt, this can leave swirl marks which can be harder to remove than a straight scratch. That’s why it’s always important to have a clean area to work in. If you are using a machine polisher, you can have the same issue with the rotational pad, it can cause the same damage. If the cloth or pad is dropped, put it off to the side and use a clean one. Don’t risk damaging the paint.
As you can see the paint’s shine is coming back and with the wet sanded surface, you’re left with a crisp and clear image. When polishing a touched up area, it’s best to go further back on the existing old paint so the paint will match and you won’t be left with one shiny area. This will be the final shine of the paint and when done correctly, this should maintain a shiny finish.
After a bit more time, here is the final shine. As for wax or another type of paint sealant, this should only be done when the paint is fully cured. Cure times for paint can be anywhere from a month or longer, this does vary between paints, weather, thickness and quality of products used.
Moving onto a two-stage paint, this involved a clear coat. The clear coat as pealing on these fender flares so they were removed from the truck, sanded down, has a primer applied, then a base coat which is the color, and finally a clear coat. Again you will need to ensure you do have enough paint to work with. If you sand through the clear coat, the final finish is damaged and you may need to apply more clear coat or have to redo the surface altogether.
Same steps as before, make sure the paint is cured enough to work with. These were left for a few weeks by the time I got around to polishing them.
Ensure the surface is clean, pre-wet the area and that sandpaper will also need to be pre-soaked. Start with 1000 grit to remove the majority of the orange peel. Considering these a curved sure, either use a very flexible backing pad, a soft foam block or if you’re comfortable enough, use the palm of your hand. Only apply light pressure, allow the sandpaper to glide over the surface.
Once most of the surface imperfections have been removed, move onto 1500 grit sandpaper. Rinse the area as needed, in this case considering I’m only sanding clear coat, the sanding residue will be a milky color. If a color is shown, then you’ve gone too far and have hit the base coat color.
2000 grit is intended to remove the 1500 grit marks and it’s fine enough to move onto the polishing process. Rinse the area and sandpaper as needed, keep the area well lubricated and work evenly across the surface.
Drying the surface will show the finish before moving onto polishing. Now I’ve only wet sanded the outside visual area, the area inside the fender well has been left as is. That way you’ll see a comparison between the original surface and a polished finish.
Using the same polish as before, apply it to a cloth or pad and then work it into the surface. Medium pressure is needed to help cut back those sanding marks and bring up a final shine. Again only clear coat is being polished so you won’t see color on the cloth. If you see paint color on the cloth, you’ve polished through to the base coat. With single-stage paints, it’s normal to see paint color on your polishing cloth.
With the fender, as an example using a machine polisher. There are various abrasive ratings of pads available, I’m using a fine polishing pad with the same polishing compound as previously. It’s much easier using a polisher, however, it’s much easier to damage the paint surface. Just allow the weight of the polisher to lay on the surface, do not apply excessive pressure or hold in the polisher in one area. Work across the surface evenly and as you can see the shine is coming back.
Just like before you’ll need to let the paint cure before a wax or sealer is applied. When the paint is curing, it gives off gases and if it doesn’t breathe properly, this may have negative effects on the curing process.
Any access polish is just cleaned away using a soft microfiber cloth.
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Participated in the
2 years ago
I am trying to put my head around this process. I've been told by others that what I am trying to achieve probably needs to be done by Auto body refinishing standards. My project is to refinish some drinking cups to be used as micro-planters for seedlings. They will be outdoors in Minnesota weather between late May to Late October. The stages I am understanding here ARE:
• Primer/Base Coat
• Paint/Pigment Layer
• Over Coat
• Sanding (1000, 1500, down to 2000 grit)
• Sealant/Water Proof
• Final Buffing/Polishing by hand
Am I understanding these stages correctly?
What is the polishing fluid used? Brand Name?
Thank you for your patience with this unusual question.
St. Paul, MN USA
Question 2 years ago
Hi I am compounding new paint and have been at it for a while now and believe I am possibly through the clear coat a a I am now seeing colour in the water but there is still no/ very little shine.
I am thinking I didnt lay down enough clear and so will give it another good coat.
I am using aerosols and understand it goes on thin so hence my wanting another coat.