Raw wood purchased from the lumberyard or a home improvement store is usually a little dusty and shows blemishes, marks, and dents on the surface. That means that if you stain over the piece right away, you’ll end up with a blotchy mess. The true grain will only show if you sand the wood first.
To sand wood, start by using a pencil to lightly scribble a line on it. Then use 60-grit sandpaper in the direction of the grain until the line is gone. Vacuum away the sawdust and repeat the process with higher-grit sandpaper, gradually going from 80 to 120 and then 180 for the best results.
Let’s take a closer look at how sandpaper works, the differences between low grit and high grit sandpapers, and the kind of sandpaper you should choose depending on the kind of wood you have. We’ll also take a look at the steps for sanding the wood, along with tips to keep in mind to get the best results.
How Does Sandpaper Work?
Sandpaper basically scratches the wood’s surface and removes a very thin layer from the piece of wood you’re sanding. When you sand, you scrape away some of the material from the wood’s surface to contour and shape the edges or remove all imperfections on the piece of wood.
Low-Grit vs. High-Grit Sand Paper
Sandpapers are available in various grits. The lower the grit number, the coarser the sandpaper, which means a higher grit translates to smoother sandpaper. You can often purchase sandpaper in a pack with a range of grits, like this 48-piece set (on Amazon).
Most wood projects usually involve sandpaper between 240 and 40 grit, except wood floor sanding, which involves 24-grit sandpaper. You can also find sandpapers with a much higher grit like 400 or 1,000, but those are for very specific uses such as autobody work.
Sandpapers with a higher grit create fine sawdust that clogs the wood pores and inhibits finishing and staining. That’s why it’s better if you don’t exceed 180 grit unless you want to close the wood pores.
Compared to high-grit sandpapers, lower-grit sandpapers get rid of more wood, but they leave behind deep sanding marks. For this reason, most projects typically involve the use of multiple grits.
Your goal should be to start with a lower-grit (course) sandpaper that can easily eliminate the worst defects. Then you can move to higher-grit sandpaper (less coarse) to remove the scratches left behind by the coarse grit you initially used.
How to Choose Sand Paper Based on Your Wood Type
The grit you should start with depends on the kind of wood you buy. In the case of inexpensive softwood, you should start with the lowest grit of around 40-60 to get rid of manufacturing marks, flaws, and stains.
If you have pre-sanded higher-quality lumber, you can start at 80 grit, but it’s better not to exceed that, especially if you want to stain the piece. An 80-grit paper is also a good place to start if you want to sand shaped or planed wood.
And if you have a smooth piece of wood with no surface defects, planer marks, or deep scratches, you can start at 100 grit.
For most kinds of woods, you won’t need sandpaper finer than 220 grit. But you might need to go a bit higher and get 320- or 400-grit paper to remove visible scratches from wood that has a very dense grain, such as ebony.
Hand vs. Electric Sanding
With hand-sanding, you get more control over how you shape the wood’s surface. Plus, it lets you address recesses and corners that are impossible to reach when using a machine.
Of course, hand-sanding takes a lot of time, and electric sanding is much faster, but the former is also quieter and doesn’t cause dust to be spewed all over the place.
Meanwhile, electric sanding is relatively hassle-free, quick, and less tiring than hand-sanding, but the finishing that you get with the latter is much better.
How to Sand Wood
If you don’t sand correctly, you’ll scratch the piece. Even though you might not be able to see the scratches, they’re definitely present. And they’ll be highly visible if you use wood finish or wood stain on the piece of wood, especially since the finish of the scratches is different from the rest. That’s why it’s important to know the right way to sand.
So, here’s what you have to do:
1. Use a Pencil to Draw a Line
Draw a line on the piece of wood using a pencil while making sure that you don’t press very hard. Be careful since you don’t want to make any indentation on the wood; if you do, it’ll be difficult to remove the pencil line.
2. Start With the Lowest-Grit Sandpaper
As mentioned earlier, the grit you should start at depends on the kind of wood you have. So choose the lowest-grit sandpaper and sand in the direction of the grain until the pencil mark goes away.
If you’ve purchased inexpensive lumber, you might need to sand some more if you can still see dents and marks. If you don’t remove these marks, they’ll stand out when you add the stain, so keep sanding.
Make sure you remove any marks that you see with the lowest-grit sandpaper and then move on to higher grits. Keep in mind that higher-grit sandpaper isn’t for removing flaws; instead, it’s used for removing the sanding marks from coarser grits.
3. Make Sure You Remove All Marks
Before moving on to the next grit, make sure you remove all the manufacturing marks. And it’s very easy to check that — all you need to do is wet the wood and all the marks will stand out, so you’ll know if you need to sand further using a lower grit.
You might see some marks because of the sanding, but you can ignore them for now since you’ll deal with them with the next grit.
Make sure that you match the product you use to wet the wood with the kind of finish or stain that you’re going to apply. So if you’re going to be using an oil-based finish or stain, you should wet the wood using mineral spirits, and if you’re going to be using a water-based finish or stain, then use denatured alcohol (on Amazon) or water.
4. Get Rid of the Dust
Remove the sawdust in between grits so that the lower grit and the bigger sawdust pieces don’t come between the wood and sandpaper when you’re sanding with a higher grit.
If you don’t remove the sawdust, you’ll end up with larger scratches on your piece of wood, which is what you want to avoid.
There are many ways to remove sawdust. For instance, you can vacuum up the dust or use a wet rag (remember to use the right liquid to wet the rag) or tack cloth (on Amazon).
5. Use a Higher-Grit Sandpaper
Repeat the steps above (except step number 3, since you already removed the manufacturing marks when using the coarsest sandpaper) using higher-grit sandpaper. So, if you started with a 60-grit paper, you can go for an 80-grit paper next before moving on to 120-grit sandpaper.
In most cases, you won’t need to exceed 180-grit since using that starts closing the wood pores, preventing the stain from being absorbed into the piece of wood.
Tips to Keep in Mind
To make sure you get the best sanding results without too many noticeable scratches on your piece of wood, here are a few more tips to keep in mind:
Sand in the Direction of the Grain
Sanding in the direction of the grain can minimize scratches in two ways. First, scratches that exist when you’re done sanding will blend right in with the grain. Of course, some of them might still be present, but they’ll be unnoticeable since they’ll resemble the grain of wood.
And second, scratches that are against the direction of the grain are very difficult to move. So if you sand against the grain using low-grit sandpaper, you’ll end up with big scratches on the piece of wood that you won’t be able to remove (they’ll forever be embedded in your piece of wood).
Plus, these scratches are very obvious, taking away all the beauty of the piece of wood.
Use Light Pressure
Another way you can reduce the number of sanding marks on your piece of wood is by sanding while using very light pressure instead of applying heavy pressure. You don’t need to exert too much energy yourself; instead, let the sandpaper do all the work for you.
In other words, there’s no need to press the sandpaper down into the wood. All you need to do is lightly hold it to the wood and rub it back and forth. This will provide enough pressure for the sandpaper to do its magic.
Pressing too much will result in deeper marks that are much harder to remove, and it won’t provide any benefit either. So, just use light pressure and save yourself the extra work of removing the marks.
Choose the Right Grit
As discussed earlier, sandpaper is available in various grits, and it’s very important that you choose the right one. Sandpaper ranges from very low grit like 60 grit (which means very coarse sandpaper) to very high grit like 220 or 320 grit (which means very fine sandpaper).
When sanding your project, make sure you start with a low grit and go higher. This will take a long time, but doing so will deal with all the rough stuff before you can move on to higher grits.
Also remember that as the grit number of the sandpaper will increase, the finish will become smoother and less material will be removed from the piece of wood.