Can You Sand Spray Paint? (DIY Wet Sanding Explained)

Sanding is smoothing out a rough painted surface, like wood or rusting metal, by scrubbing it vigorously with fine grit sandpaper.

This sanding involves a type of fine grit sandpaper that, when coated in water, acts as a powerful abrasive. It is used to create a nice glossy shine and scrape off particularly tough layers of paint. 

This sanding will scrape off and smooth the plastic surface out of the Rustoleum spray paint. However, that is hinged on whether you allow it to Rustoleum spray dry beforehand. When spray painting is coated with a finisher and given the chance to dry on a surface, it can make the rougher patches of that surface easier to see.  

This will benefit you, as it means you can use this sanding to remove those patches easily. Additionally, it gives the paint a nice, shiny look when finished. 

This sanding is also uniquely abrasive when compared to its dry counterpart. That will mean two things you’ll need to factor in when using this method. 

One, it can remove coatings that dry sanding cannot. 

Two, you need to be very careful while doing it. It is far too easy to accidentally scrub too hard while wet sanding, and leave behind scuff marks that are difficult to remove. 

Okay, A good sprayed-on paint surface results from thorough preparation, patience, and light all the coats of paint. 

So we’ve established that you can wet sand paint. But can you do so when it’s wet? In other words, you might be wondering how long to wait before wet sanding spray painting.

There are a few reasons you might want to wait until spray paint crackle has dried before starting to wet sand. 

On materials like wood, dried spray painting can help highlight the textured surface patches on the surface, making it easier to determine where to focus your sanding efforts. And in general, dried spray painting is just easier to wet sand than wet spray paint. 

So, how long to let spray paint dry before sanding? Ideally,  the recommended duration is roughly 30 minutes as most spray paints dry faster. Then, after carefully sanding the surface, apply another coat of paint.  

Wet sanding between spray paint coats is an excellent way to surfaces while also ensuring your sanding hasn't made your coat uneven by scraping off too much loose paint. Once everything looks nice and even, you can put on a clear coat spray to ensure it stays that way. 

Wet sanding requires a waterproof sandpaper designed to become more abrasive when wet. A sanding block or a sander is needed to hold it, plus some water to soak the paper in. 

Different sandpapers have different grain sizes. Finer grains mean a more effective abrasive. The closer you get to the finishing coat, the finer the grain size you should be using, and the more careful you need to be with your sanding technique.  

For this reason, it’s good practice to have two or three types of wet sandpaper on hand for your project. Of course, the specific grain sizes you choose to use will depend on the material you're painting, so research which papers work best for you. 

There are several steps you will need to take for wet sanding paint. 

First, soak the fine grit sandpaper in the water while your first coat of spray paint dries. The water on the fine grit sandpaper will unstick stubborn particles, making it easier for the paper to do its paint job. Doing this helps the paint stick to the surface better.

Then, using a sander or sand block, carefully sand the spray paint to eliminate the most prominent rough textured surface spots. Remember, you’re not trying to smooth surface it out completely, at least not yet.

For now, you just want a general sanding of the surface. Although it does depend on the surface material, you probably want to use 200 grit sandpaper for this stage. 

Apply a finisher to the paint job, and leave it to dry overnight. After 24 hours, the spray paint will have revealed uneven portions of the surface, which your first round of sanding might have missed. 

Soak your fine grit sandpaper again, preferably one of finer grain size, and start another round of wet sanding. 

Usually, two or three coat of spray paint job is recommended before you start on the clear coat. You should sand in between each coat of spray paint you apply to keep the paint nice and even across the surface you're working on.  

The final round of sanding happens right before you apply the clear coat of spray paint and uses the fine sandpaper. Once again, it depends on the surface, but sandpaper for this final step tends to be in the 1000-2000 grit range. 

This is where you need to be extra careful, as such an effective abrasive can easily strip away the layers of paint you’ve spent so long working on! 

Finally, apply the clear coat, and admire the results of your hard work! 

Always remember to check the type of fine grit sandpaper you’re buying. If it's not advertised as wet fine grit sandpaper, you probably shouldn't use it for this sanding. 

You can also use the internet to determine which grain size works best for your project. Remember: the finer the grain, the more gentle you need to be while sanding. 

This sanding, combined with any form of spraying paint, inevitably leads to droplets of liquid paint dripping onto the ground. So if you’re sanding spray paint, be sure to do it outside or you may end up with drips to fix later.

When spraying paint with single-stage paint or paint which does not require a clear top coat, you should check with the manufacturer before deciding to wet sand.

The clear top coat is mixed directly into the paint, sanding could strip away the much-needed UV protection that the clear coat usually provides. 

So, can you sand spray paint? Wet sanding is a great way to even out the painted surface of your project, and it provides a strikingly glossy visual once the process is complete. 

If you’re being careful, you can apply this technique to spray paint as well.