To wet sand a car after painting, you'll use progressively finer grits of sandpaper (like 1000, 1500, 2000, 3000) with water and a sanding block to smooth out imperfections like orange peel and dust nibs, working in small sections with light pressure, then finish with polishing compounds to restore gloss, ensuring the paint is fully cured first.
Tech Tip : Add dish soap into your water when wetsanding to help the block cut PLUS wash away the sludge from sanding!
Step 6: Use 1,500- to 4,000-ultra-fine grit for wet sanding imperfections and polishing the surface after a clear coat.
Common Wet Sanding Mistakes to Avoid
Knowing what not to do is just as important as proper technique. Sanding Through the Clear Coat The most costly mistake is sanding through to the base coat or primer. Once you do this, you'll need to repaint. Clear coat is typically 1.5-2 mils thick.
It's best to use a backing pad when wet sanding to achieve a uniform finish. Instead of using small circles as you would with dry sanding, wet sand in a straight line, first horizontally and then vertically.
Many different liquids can be used in wet-sanding, here are some popular examples: Mineral spirits. Naphtha. Water, with a small amount of liquid detergent.
The process of wet sanding involves sanding the area with dampened sandpaper to create an even surface, allowing the existing paint to bleed into any gaps. However, it can be difficult to use the right pressure and avoid removing any deeper paint layers.
I would wet sand in a couple of days and wait a week to buff. It needs some time to gas out.
After the car has been wet sanded, you can break out the polishing compound. We have successfully used inexpensive polishes to bring the shine back to our paint. It can be applied by hand or with a random orbital polishing tool.
If you choose wet sanding you must be patient. It will take a week or two of applying thin coats to build up the scratch before wet sanding.
Allow more time at cooler temperatures. Dries to touch in 20-30 minutes and is fully dry in 1 hour. When dry, surface can be immediately recoated, top coated, or wet sanded.
Physical Benefits
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.
The biggest disadvantage of wet sanding is that the water obscures my work. I have to keep wiping the surface dry to check on my progress, then wet it down again. That's just too tedious for me.
Step-by-Step Sanding Process
TIP: Add Car Wash Soap to Your Wet Sanding Water
A few drops of car wash soap in a spray bottle filled with clean water provides these two benefits, 1: The car wash soap lubricates the surface to make it easier to physically push the sandpaper and backing pad over the surface when making sanding strokes.
1500-4000 Grit
As some of the finest sandpaper grades for car paint, grits above 1500 are for the final touches on a paint job. Wet sand using these ones on base coat, or even after the clear coat is applied, to achieve a high-gloss finish.
How To Polish Your Car?
The Golden Rule of Sanding means not skipping more than one grit through each step of sanding a surface. This is a basic rule anyone should follow whether they are working with metal, wood, or any other surface. Every scratch you make must be removed by the next finer grit.
It may help to take a pencil and make light notations on the wood so you can remember where you've sanded. Once you have finished the rough sanding, you can hand sand the project with 220 grit sandpaper. This may eliminate some of the swirl marks.
Sanding between coats helps create a smooth, even surface and improves paint adhesion. Each coat of paint can leave behind small imperfections such as dust, air bubbles, or brush marks. A light sanding smooths these out, allowing the next coat to bond better and look more uniform once dry.