Wet-Sanding Spray Paint Before Clear Coat – How To Do It?

Clear coat application is crucial for paintwork to have a great final finish. Nevertheless, it is also a procedure where many issues and challenges could show up that might result in various paint flaws. It is crucial to take into account the elements that affect the clear coat’s final appearance when it is applied to the surface in order to ensure proper application.

The behavior of the clear coat on the surface will be influenced by how well the base coats of paint are applied. However, to apply a clear coat on an already spray-painted surface, you need to do some wet-sanding to enable the clear coat to adhere to the surface.

Wet-sanding is a delicate procedure; you do not want to sand through the paint job because if you do so, then it will require starting from scratch. When adding a clear coat, proper preliminary sanding, polishing, or washing of the surface is crucial for a top-notch final result. 

This article will discuss the wet-sanding process, and these are the points that will be focused on:

  • Preparing the surface before sanding
  • Wet-sanding stage 1
  • Sanding to fine out the scratches
  • Is primer required?
  • Spray painting the base coat
  • Applying the clear coat
  • Buffing the clear coat

Preparing the Surface for Wet-sanding

To properly clean the area to be painted, you should use a large bucket filled with warm water and add some dish soap to it. Then, they wash the surface using a sizable sponge, working their way from top to bottom. After washing the entire area, they should carefully dry it off with a lint-free towel.

Dish soap is soft enough to rinse off everything without creating a soapy film. Washing ensures that the surface is clear of oil, wax, and grime. If you have a sander, you can load it with sandpaper and begin sanding any scratched-up parts. This preliminary procedure will help prepare those regions for receiving the priming, base, and clear coats, even though you will eventually sand the whole surface.

It would be best if you manually sanded any corners and minor cracks to make sure the area is completely ready. The sanding equipment will not reach such tight spaces; use the 180-320-grit gauge sandpaper for this stage.

Wet-Sand the Entire Area using 1000-1500-Grit Wet Sandpaper

Particular wet sandpaper, as well as a water-filled spray bottle, is required. You should spray some water on the surface and then begin sanding it back and forth, not in a circular motion. Continue with these steps, replenishing the bottle of water as necessary until the entire section is smooth.

If the coat of paint you are replacing or repairing is really spotty, then you should sand the surface of the frame until it is completely bare. If the paintwork was not poor, to begin with, simply sand the surface until it is uniform and smooth.

Wet-sanding produces a surface that is incredibly smooth as opposed to the rougher surface produced by ordinary sanding. People should not be concerned with the amount of water they spray because the area cannot be overwet. If you do not have a sander, you could use sanding blocks made of rubber.

As you rinse for a second time, ensure that you pay close attention to the whole panel; if there are still some areas of concern, resand them to ensure a uniform surface. Next, dry the surface with a towel after properly rinsing. Re-rinsing the surface makes sure that all of the tiny paint and sanding flakes are removed.

Sanding Again to Fine out the Scratches

The process is repeated using 2000-grit sandpaper to remove the tiny scratches left behind by the 1000 grit paper. Sometimes individuals will polish with grits all the way up to 3000 to speed up the process, although this is probably more out of preference than any particular need. So, just go with what suits you.

On rare occasions, deeper scratches will appear on the paint as a result of either finer scratches that will not disappear with the 2000-grit or dirt particles that your paper has dragged onto the paint. That simply means you will have to go back and carry out the process once more.

Do I Need to Apply Primer?

No, but if you would prefer, you can opt to prime the surface after wet-sanding. However, the base layer and some of the clear coat that was removed work perfectly as a primer for a fresh coat of paint. You will have to use a primer to stop corrosion if you burn right through the clear coat on top and the paint down to the bare surface.

Nevertheless, take heed. It is only applicable if the surface is nearly faultless. Essentially, it means that there should be no signs of flaking, corrosion, deep scratches, or other types of flaws. If the panel is heavily scratched, the next best option is to sand down to the base coat in order to remove the blemishes.

Spraying the Base Coat

The initial base coat should be sprayed on, and it should be allowed to dry for around 20 minutes. You should check the base coat directions to see if thinners must also be added. It is advisable to use steady, even strokes while holding the sprayer 6 to 10 inches away from the surface, moving from left to right instead of up and down or in swirls.

After the first application of the base coat is dry, a second coat can be sprayed, continuing to apply using the same method of making slow, even strokes. It is an excellent opportunity to inspect the whole area and make sure everything is level.

Before applying the clear coat, allow the base coat to dry fully. The base coat will typically dry in around 30 minutes, but it may take closer to 60 minutes, depending on the humidity and temperature. The surface is dry when it feels soft and smooth and does not drag when they touch it.

Applying the Clear Coat and Finishing the Job

The first coat of clear coat should be applied over the paint evenly. You should put the clear coat into the sprayer while paying attention to any manufacturer’s instructions on the can. Ensure you begin from the top and gradually descend to the bottom, spraying from left to right employing lengthy, even strokes.

After this initial coat, wait ten minutes before adding the second coat, ensuring that the entire surface has an even coat because the clear coat must be noticeable as it is applied to the material. When the clear coat feels smooth when touched rather than sticky, it is dry.

Applying the second layer is done after the first coat has dried. You should ensure that you cover the entire surface with even, smooth strokes. Although two coats are typically plenty, you could add a third if you would like to or if the two coats were extremely thin.

Lastly, you should remove the masking tape, sheets, or newspaper that were covering areas that you did not want to be reached by paint. Prevent the material from rubbing or sticking on the clear coat by moving gently through this process. Ignore any remaining tape residue for the time being; it can be removed later by rubbing it.

Buff for a Glossy Finish

Before buffing, you should ensure the clear coat is totally dry. If you do not have a buffer, rent one from their neighborhood hardware store. If you leave the buffer on any one part of the painted surface for too long, it may burn or wear down the freshly applied paint. The best way is to use a low-speed setting and buff it delicately but rapidly. The process of buffing the surface is optional, but it does make it look shiny.

Final words

In summary, clear coat paint has no pigments and therefore adds no coloration to the painted surface. It is basically a transparent resin layer put over colorful paint. A clear coat finish is used on almost all surfaces, from wood to metal nowadays. However, this clear coat cannot be applied before passing through some preparation stages.

First, the area to be painted needs to be cleaned using clean water and soap with the additional sanding off of corrosion after drying. The other stage is wet-sanding to smooth out the surface and remove blemishes; if the panel has spotty paint, then the surface must be wet sanded down to the bare material.

Any sanding particles and dust are removed by thoroughly rinsing the area in readiness for the primer if needed and the subsequent base coat stage. The clear coat is applied twice after applying primer and the two base coats to add a gloss. The primed surface is wet sanded to smoothen it up before spraying the base coat. The buffering is done at the end to make the surface shine and give the surface extra appeal.