It is often advised to sand before and while painting but can you sand water-based paint? Here is the answer to that.
You can sand water-based paint to improve paint adhesion and even application of the paint. Water-based paint can be sanded using fine-grit sandpaper after the paint has fully cured. Sanding helps to remove imperfections or pimples that appear after the water-based paint has dried.
But that’s not all. This post reveals more about sanding water-based paint including the type of sandpaper to use on water-based paints.
So let’s dive in to discover more.
Do You Sand Between Coats Of Water-Based Paint?
You don’t need to sand between coats of water-based paint unless the previous coat is severely affected by imperfections, bumps, and grain. Water-based paint doesn’t produce any sheen or gloss and the paint also adheres to itself strongly. So there is no need to sand between coats of water-based paint.
Sanding between coats of paint is usually advised to help with paint adhesion and to ensure a smooth finish.
However, while using water-based paint, sanding between successive coats is unnecessary. This is because water-based paints stick or adhere to itself properly. This means that successive coats of water-based paint will bond well to the previous coat.
Also, water-based paint is not usually affected by dust nibs and grains as much as oil-based finishes. This is because water-based paints dry within minutes so the paint isn’t wet long enough to allow dust to accumulate on the coating.
The water-based paint adheres to itself properly and is not heavily affected by imperfections. So, there is usually no need to sand between coats of water-based finish.
Sanding between coats of water-based paint is done if the previous coat is severely affected by dust, imperfections, or pimples. This usually happens when the surface isn’t properly prepped before painting.
You might also need to sand between coats of water-based finish if you are painting a vertical surface like a wall. You have to sand lightly between coats to prevent the paint from dripping on the floor. Asides from these situations, there is no need to sand between coats of water-based paint.
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How Long Before You Can Sand Water-Based Paint?
You need to wait until the water-based paint coating has cured and hardened before you can sand it. It takes between 2 hours and 24 hours for water-based paint to completely cure. Only after the paint coating has cured before you can sand. On average, you have to wait 12 hours before you can sand water-based paint.
There isn’t a specific time frame to wait before sanding water-based paint. How long to wait before sanding depends on the type and brand of water-based paint that you applied.
Other factors that determine how long to wait before sanding water-based paint are: the surface the paint was applied on, the room temperature, and the level of prep work that was done before painting.
All of these factors affect the curing time of the water-based paint and only when the water-based paint has cured can you sand.
If you sand water-based paint before it has cured, you risk ruining the finish. Sanding water-based paint that hasn’t been cured will scar the finish making it cloudy.
Also, the successive coats of water-based paint that you apply to the surface wouldn’t sit well and would begin to peel off after a few days. You might also notice bubbles forming on the base coat that was applied earlier.
The bubbles start to appear because of holes and dents that were left behind when you sanded too soon. These holes allow air to sift through the water-based coating making it possible for bubbles to appear and ruin the finish.
So now you know how long to wait before sanding water-based paint but what type of sandpaper should you use to sand water-based paint? Let’s find out.
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What Type Of Sandpaper Should You Use To Sand Water-Based Paint?
You should use fine-grit sandpaper to sand water-based paint. Fine-grit sandpaper such as 240-grit and above should be used to sand water-based paint after the paint coating has cured. Using coarse or medium-grit sandpaper on the water-based coating will scar the coating and peel the finish.
Sanding water-based paint is different from sanding the surface to be painted. When sanding the surface to be painted, you are required to start with at least medium-grit or coarse sandpaper. This is because you need to strip the surface off the old finish, dirt, grime, and grains.
To do all these, you need abrasive sandpaper so using medium-grit or coarse sandpaper is ideal. However, when sanding water-based paint, you are not stripping the finish. You just want to abrade the finish a bit by creating tiny scars so the next coat of water-based finish can bond to the sanded coat.
You are also sanding to remove any pimple or imperfection like bumps, dust nibs, and brush marks that appear on the coating after it has dried. To do all these, fine-grit sandpaper is a perfect choice.
Fine-grit sandpaper is designed with tiny bristles that wouldn’t cause heavy damage to the water-based coating. So while sanding water-based paint or any type of finish, fine-grit sandpaper from 240-grit and above is a perfect choice.
Another thing to know is if you should dry-sand or wet-sand water-based paint. More on this is below, so keep reading to find out.
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Should You Wet Sand Or Dry Sand Water-Based Paint?
The final coat of water-based paint should be wet sanded because wet sanding is less abrasive than dry sanding and is less likely to scar the finish. Dry sanding should be done only between coats of water-based paint. That’s because dry sanding smoothens rough coating quickly.
When it comes to sanding paint coating, you can either wet-sand or dry-sand. Dry sanding is done by rubbing fine-grit sandpaper against the water-based paint coating after it has cured. To dry-sand, all you need is fine-grit sandpaper and maybe, a pair of work gloves.
Wet-sanding is done by rubbing fine-grit waterproof sandpaper against the water-based paint coating. The main difference between these two is that wet-sanding is done using a lubricant, usually water. So, the water-based paint coating is usually sprayed with water and then sanded using waterproof sandpaper.
However, wet-sanding should be used on the final coat of the water-based paint coating. This is because wet sanding is less abrasive than dry sanding. Wet-sanding also removes less material than dry-sanding and it results in a smoother finish.
Dry-sanding on the other hand should be used while sanding between coats of water-based finish. That’s because dry-sanding is more suited to removing pimples and imperfections that may appear on the coating after it has dried.
Dry-sanding is also more abrasive than wet-sanding. This means you will most likely notice scars and scratches on the water-based coating after dry sanding it. These scars are good between coats because they help with paint adhesion.
However, these scars aren’t good on the final coat of water-based finish because the final coat should be smooth and fine.
So while you can dry sand between coats of water-based paint, the final coat should be wet-sanded to guarantee a smooth and clean result.
Related Read: Can You Sand Chalk Paint?
Do You Need To Sand Before Applying Water-Based Paint?
You don’t need to sand before applying water-based paint but it’s advised to do so. Sanding before applying water-based paint helps to prep the surface for the paint application by getting rid of imperfections on the surface. You should also sand if you want to strip the previous paint or finish off the surface to be painted.
However, if the surface to be painted is smooth enough, you may not sand before applying water-based paint. Water-based paint also has good adhesive qualities so sanding isn’t necessary to improve bonding.
But remember, water-based paint is thin so if there is any imperfection on the surface, it would still be obvious after the paint coating has dried.
It is always advised to sand a surface before applying a finish. This rule also applies to water-based finishes, although not in the same way as other types of paints. That’s because water-based paint has good adhesive qualities. So, sanding to improve water-based paint adhesion isn’t necessary.
Though sanding before applying water-based paint isn’t in every case necessary, it is still advised. Sanding isn’t just done to improve paint bonding.
Sanding is a very vital preparatory step before applying any finish on a surface. Sanding helps to smoothen the surface to be painted so that the paint coating can come out smooth and fine when dry.
So, before you apply water-based paint on a surface, you should first sand the surface using medium-grit sandpaper (120 or 150-grit). Then you should move on to finer-grit sandpaper to smoothen the surface.
Another thing to know is if you can sand water-based primer. So can you? Let’s find out.
Can You Sand Water-Based Primer?
You can sand the water-based primer to smoothen the primer after it has dried. The water-based primer should be sanded by using very fine-grit sandpaper like 400-grit and above.
After priming a surface with a water-based primer, there are usually lobs, splinters, and little fibers that are raised from the wooden surface as the primer cures. These imperfections should be sanded off after the primer dries to ensure that the paint is applied to a clear and smooth surface.
Sanding after using water-based primer can be done but you should let the primer cure completely before sanding. This is to prevent ruining the primer coating. If you sand water-based primer before it has cured completely, the basecoat wouldn’t adhere evenly.
After applying water-based primer to a wooden surface, there are usually noticeable splinters and fibers of wood beneath the primer coating. This is because water-based primer bonds very strongly to the wood.
Many water-based primers bond to wooden surfaces so well that they sink into the wood. This strong bonding process sometimes causes splinters, bumps, and wooden fibers to poke out.
So when the primer dries, the coating will be riddled with these imperfections. So you should sand the water-based primer lightly after it has cured to get rid of these imperfections.
To sand water-based primer, very fine-grit sandpaper should be used to prevent smearing the primer coating. Use sandpaper from 320-grit and above to sand water-based primer.
Related Read: Does Water-Based Paint Expire?
Overall, water-based paints can be sanded but the paint coating should be sanded with fine-grit sandpaper to improve the finish. You should also dry-sand between coats and wet-sand the final coat of water-based paint.
So there you have it. If you liked this post, ensure to check out others like it on this website for more painting tips. Have a nice day.