I’m sure you probably know some basics on how to sand wood, but I wanted to really break it down to help you save time and get sanding done with minimal effort and maximum results. So that’s why I titled this How To Sand Wood Like You Know What You’re Doing.
Sanding your wood is not always a fun process. In fact, for me it comes in 2nd place for the worst part of any project (closely behind finishing). So I think it’s worthwhile to know the most practical, effective, and efficient techniques for sanding any project.
Don’t get me wrong, I love woodworking. But like most anything we do in life, there are going to be aspects that suck. I don’t make the rules, that’s just the way it is.
So when it comes to sanding, the goal is to have the smoothness needed for the finish that will be applied afterwards. Below I’ll go into detail on how this varies depending on what you’re finishing with.
Also, the sanding process should be done in a way that you won’t wear yourself out trying to flatten a surface. That’s why God made power tools. Or even if you’re using regular sandpaper, that’s why God made coarse grit.
And I’m not going to tell you that you need 8 different grits to do things properly. Maybe that’s the case in a scientific study for the absolute most perfect use of efficiently applied sanding techniques particular to the temperature and humidity levels in your region, per the species of wood used, and so on and so forth.
No.
You only really need 3 or 4 different grits for most projects, max.
And actually, 2 is usually enough. Follow the simple methods I outline here, and you’ll be sanding like a pro in no time.
Seriously, I know. I hate sanding, I know how to get it done fast, and how to get it right the first time.
I like the simplicity of the idea that ‘Coarse’ is for rough wood, shaping, and/or removing old finishes, ‘Medium’ is for final shaping and removal of planing marks, and ‘Fine’ is for finishing. (That’s how they sum it up over at BobVila.com)
My Sanding Method From 30,000 Feet (for most projects)
Sand down to flatten the board using 80 grit sandpaper and a random orbital sander. I only use this course grit if the wood is really rough or if I’m flattening the board or panel.
Remove the sawdust from the surface with compressed air.
Switch to 120 Grit and sand away the roughness left by the 80 grit. This does not take long and you should be able to tell by feel when the entire surface has been smoothened to the new 120 grit sanding marks.
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Again remove the sawdust with compressed air.
Switch to 180 grit to sand the surface smooth. This should leave a noticeably different feel on the wood, and in most applications this is plenty smooth for applying a finish on.
That’s it, that’s the method I typically follow, but there are reasons this will vary. Continue reading for a more detailed explanation.
The Finish You Use Makes A Difference
Film finishes include shellac, polyurethane, lacquer, and varnish. These finishes build up a film on the surface of the wood, essentially creating a new surface of their own.
If necessary, this film-finish surface can be sanded even smoother using high grit sandpaper, like 400 or 600, but that’s not always necessary.
But what this means is that if you’re using a film finish, 180 grit is plenty smooth and really won’t even come into play after the finish is built up.
Also keep in mind that if you are staining your project, the rougher you leave the surface during sanding, the more the stain will darken that surface.
So let’s say you want to darken the wood as much as possible with any given stain, and you intend on finishing with a film type finish, you probably should sand only up to 180 (or even just 120).
This will leave a surface that darkens much more with stain, and still finishes very flat because the film finish builds layers that ultimately leave a smooth surface.
If you’re not staining,and finishing with a film type finish, it’s still probably best practice to sand up to 180 grit.
Penetrating finishes include tung oil and boiled linseed oil, these penetrate the wood fibers and harden as they dry.
When using a penetrating finish, it may be worthwhile to sand to a grit of 220, because the wood finish is not creating its own smooth surface, and 220 does feel softer and smoother than 180, no doubt.
How to Sand Wood – The Methods and Tools
Methods for sanding are by hand using regular sandpaper backed up with a sanding block that is flat, a quarter sheet power sander (the vibrating kind), and the random orbital sander.
Each of these have their own pros and cons, as well as specific applications where they work best.
If you’re working with curves, or if your softening edges and corners, it’s perfectly normal to use sandpaper without a sanding block.
Tip – I always keep a few of the soft drywall/sheetrock sanding blocks handy in my shop. They’re like a foam block with sanding surfaces, and they work great for sanding curves, and softening corners. When they wear out, you trash them and use a new one, but they’re cheap so that doesn’t bother me a bit.
When hand-sanding flat surfaces, it’s always best to use a sanding block to avoid uneven pressure which creates coves the wood.
You can pick up sanding blocks at any hardware store, or you can just use a piece of scrap wood you have lying around.
This method works best if you attach a layer of cork board, or something with similar softness, to the face of the sanding block (not 100% necessary though, only helpful).
When sanding edges, it can help to use a sanding block in conjunction with another scrap block of wood.
This helps guide and keep the sandpaper flat against the edge of the board. See image below:
Always sand back and forth with the direction of the wood grain (if possible).
If you sand across the grain, you will likely end up with noticeable sanding marks at the end.
If you end up with these marks, you probably need to remove them with 80 grit, then work your way thru the grits once more to a smooth surface.
Using power sanders definitely saves time, but they can also leave curly marks in the wood. The risk when using these sanders is that you may not notice the curly marks until after you apply your final finish.
I’ve done this, and it’s gut-wrenching! Next you get to sand off that coat of finish after it dries, and start the sanding process over again… I’ll cover how to avoid power-sander curly marks later.
Also when using power sanders, try not to force your way through the material by applying heavy pressure. In my experience the results are best when I apply light even pressure when sanding, and it seems to remove the most material as the sandpaper heats up.
Every so often I turn off the tool and knock the dust out of the sandpaper with my hand, literally by slapping it a few times (by the way this also helps when sanding by hand with a sanding block).
How To Sand Wood – The Process
On rough wood that has not been sanded yet, but has already been ran through a planer (like what you get from a hardwood dealer or from a home store) I usually start with 80 grit sandpaper using a power sander (although your specific sanding method may vary, see above).
This stage of sanding will probably take the longest. Consider this stage the overall flattening of the wood surface. 80 grit will work through the wood much faster than the higher grits, especially when using a power sander.
What you don’t want is to find that there are uneven areas or slight hills and valleys that need to be sanded out, after you’ve already started the 180 grit stage. So when doing the 80 grit, take your time to get it right.
The way I see it is that basically sanding a surface flat is done with 80 grit sandpaper. Making it smooth to the touch is done with the others.
It may help to find the hills and valleys of the board by shining a light at a low angle, and running a straight edge across the wood in different directions. You should be able to identify areas that are low and high.
Then take a pencil and scribble some lines in the high areas. for the next round of sanding before checking again, you’ll sand evenly across the board’s hills until all the pencil lines are gone, and be sure to avoid the valleys where there are no pencil marks.
To avoid a few subtle pitfalls, it’s best at this point to remove the sawdust from the surface. You can use a brush, vacuum, or even compressed air (my favorite method).
Depending on your dust control situation, these methods may or may not appeal to you, so it is okay to use a tack cloth to remove the dust. Just keep in mind these plug up very quickly.
Now advance through each grit of sandpaper, getting higher and higher until you finish with 180. Or as I mentioned above, there are some applications you may stop at 120, and others you may stop at 220.
The grits I use are 80, 120, 180, and 220. There are additional grits between these, and some people advise you to use them all, but I have yet to see an instance when I really needed to be that precise.
So I can’t speak on the benefit of purchasing twice the amount of sandpaper, for the sake of making smaller jumps with each successive sanding grit.
But to each his own…
As you advance through the grits, you will not need to spend much time at all at each stage.
Because at this point you’re working with a surface that has been flattened already using the 80 grit, one trick I use is too lightly scribble pencil marks across the entire surface, then I just sand until the marks disappear.
Then I remove the sawdust, make new mark’s, switch to the next grit, and do it again. the higher the grit, the lighter the pencil marks need to be.
3 Ways to avoid curly marks from power sanders:
Why even worry about curly marks?
Because if you’re going to apply a stain or a protective finish on the end product, the curly marks that may have been nearly impossible to see during sanding, will stick out like a sore thumb once the finish is applied.
You’ll end up having to back-track, re-sand the project, and apply the finish again. This is not fun, believe me, I’ve done it.
So here’s a few ways to catch them early and eliminate that risk.
1 – After using a power sander with 80 or 120 grit to completely flatten the surface, switch to hand sanding starting again with 80 grit, and only sand with the direction of the wood. Then go through the grits as outlined below, using a sanding block and regular sandpaper from there on, always with the grain of the wood.
2 – Take your sanding to an extra step with the power sander, up to 220 grit (only after sanding to 180 grit of course). This will ultimately leave such small sanding marks, curly marks will likely go unnoticed if there are any. With this process be sure to remove the sawdust from the surface between each grit.
3 – After sanding to 120 and to 180, shine light on the board at various low angles to try and identify any curly marks. You can also rub on some mineral spirits to darken the grain to help identify these marks. you can probably then sand them out quickly by hand.
Softwood or Hardwood?
If you’re working with pine, or other types of softwood, you may skip the 80 grit all together. Starting with 120 could help you avoid over sanding, which creates valleys in the wood.
This is especially true if you’re using power sanders with 80 grit. You will simply remove a lot of material very quickly, which is risky.
With softwood, every stage of the sanding process will go by faster, but at the same time you will plug up your sandpaper faster. So keep that in mind as you go along.
You may need to slap your sandpaper more often.
And obviously, hardwood is just the opposite. Sanding will go slower, so starting with a courser grit makes sense.
There have been cases where I found starting with an even lower grit than my typical 80 was beneficial.
While 80 grit will usually suffice, one time I remember working with hard maple for a table top surface I was building, I actually picked up some 60 grit to flatten the surface.
But if I remember correctly, that particular ‘hard maple’ table top I made was from ‘really really hard maple’.
When and How to Sand Wood Using a Belt Sander
Belt sanders definitely have their place in power-tool woodshop. But they should not be used on every project.
They are designed to remove a lot of material very quickly.
The main benefit I find with a belt sander is that they have a larger sanding surface, and this makes for a good tool when flattening a panel, such as a tabletop.
This method can replace the need to use a hand planer on large panel surfaces.
When using a belt sander, be sure to identify the hills and valleys using low-angled light and a straightedge (this method I outlined above), scribble pencil marks on the hills, and sand away the pencil marks.
When operating a belt sander, never hold it in one spot. It should always be moving if it’s turned on and touching the wood surface.
Otherwise it will quickly create grooves in the wood at the edge of the sandpaper.
When complete, remove all the belt-sander scratches and marks using a random orbital sander or sanding block.
So overall, be very careful and only use the belt sander to flatten a large surface. Once that is complete, put the belt sander away! Use your regular power sanders or hand sanding to finish the project.
TIP – How to Make End Grain Look Better Stained
This is a common thing I see, and I’ve ran into it many times myself. When the end grain of wood is exposed, and the project is being stained (or even oiled), the end grain usually ends up looking darker than the rest of the surface.
One thing that sanding affects is how much finish the surface easily absorbs. That’s why, as I mention above, if you want a stain to finish darker, you don’t sand to a very high grit. The rougher you leave it, the darker the finish.
In this picture, the board was sanded the same all around (to 180 on top, edge, and end). The stain on the end darkened the wood more than it did on the top and the edge:
So what’s common is when someone sands a table top to say 180 grit, and sands the ends of the boards the same, when applying a stain finish, the ends look darker than the top.
So to close this gap (the difference in the darkness), you can sand the ends of the boards to a higher grit. This will close off the pores a bit more than usual, and lighten the final look up a bit.
Also don’t let the stain sit as long on the ends before wiping off excess.
So overall here’s what this may look like for a table project – Sand the entire panel up to 180 grit. Then with 220 grit sand just the ends.
When applying a stain, brush or wipe on the stain, and allow 2 minutes or less before wiping off excess stain from the ends, but allow a full 5 to 7 minutes for the top of the panel to absorb stain.
In this picture, I cut the end off and resanded but this time I sanded the end up to 220, and then restained. Notice how much lighter it is this time around:
This is just an example scenario and yours may be different, but I’m trying to illustrate my point.
Treat the ends differently than you treat the top, and you will end up with end grain that is much closer to matching the top than you otherwise would have.
That’s It – Sanding Complete
If that wasn’t painless, I don’t know what is! Seriously though, these methods work great for me, you should give them a try.
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