If you want the best finish on your next woodworking project, sanding is essential.
Of course, you can’t always count on having the best environment for sanding. Most woodworkers are probably already familiar with the process of sanding dry wood, but what happens if your work surface gets wet while you’re sanding, or before you finish sanding it?
Can you sand wet wood and can you continue sanding if your work gets wet?
In this post, I’ll explore sanding wet wood, what it does, the difference between sanding wet wood and wet sanding, and how to make the most of your work. Let’s get started!
Can You Sand Wet Wood?
Ultimately, sanding wet wood is not a good idea. While it can be done, you likely won’t get the look you desire.
If you’ve heard of wet sanding you might be a little confused, but the wet part of wet sanding isn’t actually the wood surface. Instead, wet sanding uses wet sandpaper.
Sanding wet wood is a problem for a couple of reasons. For one thing, when the wood is wet the wood fibers lift and can stand on end.
That’s why unfinished wood usually feels rougher when it’s wet. The wood fibers aren’t laying down and create a much rougher surface before smoothing down slightly as they dry.
Dry sanding wet wood tears through these fibers. You’ll remove some material, sure, but the damp wood doesn’t act the same as dry wood. Instead of getting sawdust off the wood you’ll probably get a kind of grainy mush.
Not only does that mush mean that you’re probably scratching and damaging the smooth surface of the wood, you’re also going to quickly saturate and ruin your sandpaper.
It might only take a couple of passes before wood pulp fully saturates the grit in your sandpaper, making it basically useless. You’ll get a lot less life from your sandpaper if you ever use dry sanding techniques on wet wood.
Instead, it’s better to wait a few days or weeks for wet wood to dry before you start sanding it again.
That might mean delaying work on a wood deck or shed that gets rained on, but it’s better than damaging the materials by trying to sand too soon.
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Can You Wet Sand Wet Wood?
If you’re working with wet wood, some wood workers wonder if it would be possible to use wet sanding to make the process easier and faster.
Unfortunately, no. Wet sanding is no more effective on wet wood than dry sanding.
No matter what sanding process you’re using, if you want a smooth finish you need to make sure the wood you’re sanding is mostly or entirely dry.
What Is Wet Sanding?
Wet sanding is a little different than just sanding wet wood. In fact, the wet part of wet sanding is the wet sandpaper.
This is important because it helps control how much moisture is transferred to the wood you’re working on during the sanding process. This is critical because you don’t want the wood fibers to stand up like they would if you were sanding damp wood.
This is often used as a finishing technique and isn’t really designed for use at the beginning of sanding.
Good wet sanding technique can give you smoother finished surfaces than when you dry sand wood and is best for when you need a super smooth surface.
This technique is also almost exclusively done with fine-grit sandpaper.
Unlike dry sanding, which can be done with any grit of sandpaper and can even be used as part of shaping the wood, wet sanding is exclusively for getting the right finish on your work. Whether you’re going for a smooth finish or a finish that feels (and reflects light) like glass, wet sanding can help you get there.
Wet sanding uses sandpaper that’s been soaked and wood that’s dry to help create a smooth finish.
The moisture in the sandpaper helps reduce the amount of friction, making it easier to move the sandpaper across the wooden surface, which means you can use higher grits and get a smoother finish.
What’s the Difference Between Wet Sanding And Dry Sanding?
There are a lot of differences between wet sanding and dry sanding.
For one thing, wet sanding requires that you soak the sandpaper (and sometimes your sanding block) before sanding. Most experts recommend soaking for at least 24 hours before sanding, but you can do a quick soak for 15 minutes if you’re not looking for the best finish.
Wet sanding requires fine-grit sandpaper, and can only be done by hand. Don’t try to use an electric sander for this part of the process. You’ll likely lift any loose wood fibers, damage the grain of the wood, and otherwise ruin your finish.
Dry sanding, on the other can, can usually use an electric sander and it’s less important to sand with the grain of the wood.
That’s because dry sanding is better for helping to even out a surface, getting a starting finish on the wooden surface, and prepping wood for paint or varnish.
Another big difference between wet sanding and dry sanding is that wet sanding is usually done after a layer of finishing material has been applied to the wood. You might use it after staining, oiling, or applying a sealant.
That’s important because this part of the sanding process helps create a more fully finished and smoother surface.
Wet sanding isn’t good for deep scratches or correcting an uneven surface, but it’s one of the best things you can do to create high-quality and beautiful wooden furniture.
Do You Use The Same Sanding Technique For Wet Sanding?
While some techniques from traditional dry sanding can be used for wet sanding, like sanding with the wood grain or in small gentle circles, not all of the techniques will cross over to wet sanding.
For instance, with wet sanding, you sand the wood with the grain, and only after applying at least one layer of finishing material to the project.
Another core difference is that you can dry sand green wood (wood that has been recently cut), but you can’t effectively wet sand green wood. That’s because the extra moisture in green wood prevents wet sanding from being as effective, and the current texture isn’t finished when you sand the wood. It can still shift and change over time.
When you wet sand you want to make sure you’re following the grain or sanding in small circles to create a very smooth and even surface. That’s a good idea anytime you sand wood, but dry sanding is a little more forgiving if you need to dry sand against the grain or to finalize the shape of a project.
Can You Dry Sand Wet Wood?
We’ve talked a bit about how dry sanding is a little more forgiving than wet sanding, but that doesn’t mean that dry sanding is okay for wet wood.
Even green wood needs to be dry before it’s a good idea to sand it.
This also applies no matter what kind of sandpaper grit you’re using. Whether you’re using coarse or fine grit, you need to wait to sand wood until it’s reasonably dry.
How Dry Does Wood Need To Be Before Sanding?
Wood can look dry long before it’s actually ready to work.
That can make it more difficult to handle and lead to ruined sandpaper if you try to sand too early.
All wood has some amount of moisture in it. Even seasoned and professionally dried wood will contain a little bit of moisture. The trick is controlling how much moisture is left, and helping to prevent the wood from warping or twisting as it dries.
Ideally wood should be down to about 7-9% moisture by the time you want to work with it. That way you’re sure you aren’t going to sand wet wood and everything is completely dry before you start.
Of course, you might not have the tools to check the exact moisture content of your wood, so it can be hard to know when it’s hit the right point.
On average wood needs to dry for 1 year per inch of thickness to hit the right dryness.
You can also learn how to kiln-dry wood if you want to speed up the process, but that can lead to warping and other problems until you master the process.
When Should You Wet Sand Your Wood Surface?
The primary goal of wet sanding is to get the smoothest possible surface.
The moisture is there to help smooth the friction between the wood and the sandpaper to reduce scratching while still removing that last little bit of texture from the wood.
Wet sanding is best for the highest grit sandpaper. Sandpaper that would otherwise be difficult to use because it would hold on to the wood and be hard to move.
Ideally, wet sanding is used only after you’ve already started finishing work on the project. A layer of oil or varnish is already down and that way you can wet sand to create a much smoother surface.
The finishing material also helps protect the wood underneath from the moisture in the sandpaper.
Tips For Making Wet Sanding More Effective
Here are a few tips that you can use to make wet sanding more effective and easier.
Use A Little Dishsoap In Your Soaking Water
When you’re soaking the sandpaper and sanding block, add just a couple of drops of regular dish soap to the mix. Don’t use too much, as high concentrations of soap can create a residue that needs to be removed before you can do the rest of your finishing work.
The little bit of extra soap helps reduce friction even further, making it easier and faster to wet sand your work.
Consider More Than One Grit Sandpaper
A lot of people only want to use one type of sandpaper for finishing work, but that can make your job harder than you think.
Consider using 2-3 different grits, or even more for the finest work and the smoothest or most reflective possible surface.
Start with the lowest grit you’re going to use, and work through until that sandpaper isn’t doing much and the surface is already as smooth as you can get it.
Then repeat that process for each finer grit of sandpaper you want to use until you achieve the desired finish. Try to start with at least 2 grits, but you can go up to 5 or 6 different grits and still get a noticeable improvement between each one.
Use A Little Mineral Oil
Mineral oil or mineral spirits are another option if you’re looking for something other than soap that can reduce the friction on your work.
Mineral oil serves a couple of purposes, it reduces friction and it can also be used as its own kind of finishing material. The oil will help to hydrate the wood if any of it gets under the finish, but it won’t cause the same problems as water.
That said, mineral oil can leave a fine residue that’s hard to remove and can interfere with some other finishes. If you’re considering mineral oil you need to make sure your desired finish is compatible with it.
Fill In The Grain Of Open Pore Woods
Some types of wood have a more open grain than others, which also means that they are harder to seal and can be more absorbent than other tighter-grained types of wood.
If you’re working with oak, ash, walnut or other open-grained woods you should fill in the grain before you start wet sanding.
Wood filler paste is usually the best option to fill in those types of wood. Make sure you apply the paste to the whole surface, wiping across the grain to help make sure it fills all the gaps. Wipe off the excess, and allow the paste to dry at least overnight before doing any additional finishing.
Sand lightly before applying an additional finish, and then you’re ready to wet sand without damaging the wood underneath.
Final Thoughts on Can You Sand Wet Wood?
So, can you sand wet wood?
While it is possible, it’s not recommended. Sanding wet wood will yield poor results and can potentially damage the wood itself.
It’s best to let your wood dry before sanding it for the best results.