Hand-crafted wood furniture and decorative pieces are often expensive due to the large amount of work and time that go into them. Woodworkers spend hours cutting, sanding, joining, and finishing wooden pieces.
Each aspect takes a long time, but one of the more tedious steps is the sanding. It takes a lot of repetition and clean-up to get wood properly sanded, even if you start with wood that’s perfectly dry and ready for sanding.
If you have wet wood, though, you’ve probably had to wait hours or days for it to dry out before sanding. This extra time can feel like a real pain, and it makes you wonder if there’s a way you can sand wet wood.
So, can you sand wet wood? It is not recommended to dry sand wet wood, but there is a technique called wet sanding where you soak special wet/dry sandpaper and wet sand a piece of dry wood.
There are several factors to consider when deciding whether to dry sand or wet sand wood. Not all wood needs sanding, so it can be tricky to figure out whether it’s right for your project.
In this article, we’ll dive into the details of both dry sanding and wet sanding to help you determine the best sanding method for your woodworking project.
What Is Dry Sanding?
Dry sanding is the process of using regular sandpaper to smooth down a dry piece of wood. This is usually done to remove any loose pieces of wood sticking out, level out the wood board, and help the wood take a paint or finish better.
While dry sanding is often done on raw wood, you can also dry sand a painted or varnished piece of wood to help remove that layer of paint or varnish for refinishing. There are several different kinds of dry sanding methods that you can use.
You have the option of dry sandpaper sheets that you hold and manually rub on the wood, sandpaper sponges or blocks, and a machine sander such as a random orbit sander or belt sander.
Each of these has their pros and cons, but all of them will work when sanding. Using a machine will save you a lot of muscle ache in your upper arms and core, but machine sanders cost more money upfront.
Although the machine sanders are a bigger investment, most woodworkers will tell you that it’s well worth the price to save you hours of time and muscle work.
Why Do You Need To Dry Sand Wood?
Dry sanding wood is important to smooth out any imperfections in the wood. Although sanding won’t fill large holes (you’ll need wood filler for that), it will reduce any small warps, scratches, or loose wood fibers sticking out.
Raw wood isn’t naturally receptive to taking on layers of paint, varnish, stain, or any other kind of finish. To prepare the wood for such a layer, it will need to be sanded first to get rid of that top layer of wood and reach the soft layer.
This will also help give you a smoother feel after you apply your finish. For wooden furniture such as a dining room table or chairs, you want the wood to be smooth so any family, friends, or guests don’t get splinters from little imperfections in the wood.
Tips For Dry Sanding
A good tip for dry sanding wood is to go from course to medium or fine with your sandpaper grit, allowing you to get the biggest problem areas first and then smooth out the smaller imperfections.
You will also need to properly clean your wood after it’s been sanded. Check out our article on this topic for more information: How To Clean Wood After Sanding.
While you shouldn’t dry sand a board of wet wood, you can add just a little water to help the sanding process.
You should never pour water directly onto the surface of the wood. Doing this will cause the water to soak deep into the wood and create a lot of problems when handling the wood, such as warping, swelling, and ruining the sandpaper.
Rather, the way to add a little water before dry sanding is to dip your fingers into a cup or bowl with water and flick droplets onto the wood surface. You want to be very light with the amount of water.
After applying the water, allow the damp wood to dry completely. This could be around 3-4 hours, if set in a well-ventilated area. Once it’s dry, you can sand as usual.
The advantage of dampening your wood first is that it raises the wood grain and helps any straggling wood pieces to stand up and be easily sanded down, creating a smoother finish.
Can You Dry Sand Wood When It’s Wet?
No, you should never dry sand wood when it’s wet. In this instance, we’re specifically referring to wood that is significantly damp, such as wood that’s been out in the rain or has absorbed water.
All wood will retain a small amount of moisture. It’s a natural part of wood. But when dry sanding, your wood should only retain around 7-9% moisture. Anything higher than this is a recipe for disaster.
The consequences of dry sanding wet wood include gumming up and ruining your sandpaper quickly (in a matter of seconds), an uneven surface on your wood, and a wood board that is not unusable.
What Is Wet Sanding?
Wet sanding is the process of using wet/dry sandpaper, soaking it in water for 24 hours, and using it wet to sand the surface of the wood.
It is important to only use wet/dry sandpaper for this process. Wet/dry sandpaper is specifically designed to take in water and have it not damage the grit or material of the sandpaper. If you soak regular sandpaper in water, it will destroy the sandpaper and make it unusable.
When wet sanding, you can only sand the wood by hand. You can use a block to help, but you cannot use any machine sander for wet sanding. Doing so will damage the machine and void your warranty.
Wet sanding is traditionally done after a layer of varnish or stain has already been applied. This helps the finish to soak in and achieve a truly slick surface that’s soft to the touch.
Why Do You Need To Wet Sand Wood?
Wet sanding is an important step in creating wooden furniture that needs an extremely fine, smooth finish. Because wet sanding has the added lubrication of the water, it helps smooth down every tiny piece of wood grain sticking out to ensure the smoothest possible surface.
Although dry sanding can achieve a smooth finish, wet sanding makes for an even smoother touch. Wet sanding also reduces the amount of dust, which can be very helpful for those who have sensitivity to airborne sawdust.
Often, wet sanding is used for that incredibly delicate finish that’s needed for musical instruments, cutting boards, or wooden bowls or pens that will be turned on a lathe.
You can also use wet sanding to achieve a smoother surface on a tabletop or handles of a wooden toolbox or any other wooden storage container. As we mentioned above, wet sanding is traditionally done after a layer of varnish has already been applied.
This is to help give that finishing layer a truly smooth and seamless feel. When you run your hand along the finished product, it should feel completely polished and flat. You can wet sand raw wood, but you’ll need to let it completely dry out before moving to your next step.
This could take hours or days, and your wood should be set up to dry in an indoor space with plenty of ventilation around all sides. Never lay wood pieces touching when setting them up to dry.
A final advantage to wet sanding is reducing any scratches or dents in the wood. Although wet sanding won’t fix deep scratches, it can eliminate any surface-level scratches in the wood.
Tips For Wet Sanding
One of the most important parts of wet sanding is ensuring that you soak your wet/dry sandpaper in water for 24 hours. Keeping it soaked for 24 hours will ensure that the entire sandpaper has taken up enough water to truly allow for optimal lubrication.
If you’re in a hurry and can’t wait the full 24 hours, you can choose to soak your sandpaper for only 15 minutes. This drastic time difference will cause a noticeable difference in your sanding, but it can be done this way in a pinch.
You will also need to wet sand in a circular motion. Although dry sanding can be done in straight lines or circles, wet sanding requires a circular motion. This helps grab any loose wood grain and eliminate any previous scratches.
Sometimes people choose to mix in a little dish soap with their water. This can add additional lubrication and help the sanding go more smoothly. You don’t have to use dish soap, but it certainly can help.
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