Best Practices for Sanding Wood
So I found myself looking at my child’s favorite wand, made at an actual wand shop (in sunny California), with its paint fading from good use. Then the spark hit me - I have to repaint it for her. So I looked into that process and that’s where I learned about sanding, since the wood needed treatment in my case too. Hope that information I learned helps you in any way!
How to Sand
Before we talk about the recommended practices for sanding wood, I think it’s important to understand the overall process first. Here are the fundamental steps you’ll need to know.
The simplest, and most often used method of sanding is the hand sand. This only requires you to purchase sandpaper from the local hardware section or store. A little elbow grease, and you can easily sand anything with your fingertips. If you choose to use your hand to back the sandpaper, you should know a few things.
An efficient way to sand is to fold the large sandpaper sheets into sections. Some do thirds, some do quarters, it kind of depends on your hand size and the project size. This way, you have a better grip on the paper, and you efficiently use the entirety of the sheet.
The sandpaper will lose its grit as you use it more. So by sectioning off the sheet, you can get back to a nice, gritty texture to continue to sand down the rest of the wooden piece.
When the sandpaper’s grit no longer has its original “catch,” the sanding will be ineffective, and will just spread more wood dust along the surface. Catch refers to when you trace your finger along the surface to feel its coarseness. If the paper feels smooth in comparison to its original state, you should replace it.
Obviously, this method is very effective if you want to do small spots, but sanding a large amount of wood by fingertip is going to be long and likely painful. In order to save yourself the energy and time, consider a sanding block for slightly larger projects.
A sanding block is an accessory that attaches the sandpaper to a piece of wood, plastic, or whatever strong material. This gives your hands a more sturdy object to grip, making the sanding process less harsh on your hands.
Having a cushion under the flat sanding block will be important if you need to maintain a flat surface on the wood that you are sanding. If the sanding block is too firm without any cushioning, the hard edges will create uneven sanding, and also quickly wear out those pressure points on the sandpaper itself.
Cork, or a softer rubber, can act as an effective cushion between the block and the paper.
Some will make their own sanding block so that it fits their personal preferences, like hand fit, weight, and look.
Make sure you latch down the paper well to the sanding block or else the movement of the paper as you sand will make for a frustrating experience.
The third main option for personal sanding is to use a mechanical sanding machine.
If your project requires larger surface area coverage, a mechanical sander may be the best option in regards to saving time and energy. That said, it may not be the best option if your project needs require fine detail work or a smaller surface.
Just because it is mechanical, doesn’t mean it will be faster. Often, people psych themselves out by thinking that sanding is the hardest or most annoying part of the process. And that a sanding machine will be the answer to all their problems.
You may end up disappointed, like I was, that it still took a lot of time and energy for a while until I finally got familiar with the equipment. Unless you have many projects in a row to work on, it may take you a while to learn the errors in your approach.
Not trying to scare you, I just think you should know that it also takes time to master a mechanical sander.
Examples of different types of mechanized sanders are: Belt, Orbital, Random Orbital, and Detail Sanders. They all have their own useful traits that are better suited for certain purposes.
All that said, any mechanized sanding should always be inspected. Then if there are any rough parts that were missed, spot finish with a delicate hand sanding. As always, in the same direction as the grain. Just a tip to keep your attention to detail high.
How Much to Sand
This part gets a little tricky because I don’t want to give you the wrong advice.
To know how much you need to sand, you’ll need to be aware of the current state of the wood, as well as your expected ending point.
I can’t just tell you to start with 40 grit and end with 220 grit. By the way, there is a numerical classification system for sandpaper. 40, 60, 80, 100… all the way to 400 and potentially beyond exist. The lower the number, the harder the grit. So, 40 grit sandpaper would be used to start the sanding process for wood that is very rough. 400 grit sandpaper would be something you use to give penetrating oil a more effective take as a final finishing step.
You should always sand incrementally, so if you start at 100, then next you should go over the wood with 120, then 180, and so on until you feel the desired smoothness.
Essentially, you need to figure out how rough the wood currently is, then you’ll know your starting grit. Here are some approximations of the grit you may need for your job.
If your project needs leveling, consider starting around a 40 to 80 grit paper.
If your project is already level, has some deeper gouges, some varnish or paint left over - try 100 grit paper.
As long as the above conditions are addressed, you may want to start with 120 grit paper.
Sometimes, people will give themselves a visual aid to ensure they covered the entire surface. You can use a pencil to mark the top layer, that way when the pencil marks are completely gone, you’ll know you covered every part you wanted. Another is to inspect the wood by light to see if there are any inaccurate reflections.
Another tip I learned from experience is to not press down on the mechanical sander while sanding. If you press down, you will create uneven pressure points on the sandpaper, leading to uneven results in the wood.
Sand With the Grain
For beautification purposes, this may be among the most important steps in the sanding process. If you’ve ever worked with any good-looking lumber, you’ll know you want to accentuate that natural beauty.
Every piece of wood contains pores in its surface that organically create a pattern, called the grain. To preserve this grain, you should always sand in the direction of the grain. This applies across the board, including on edges and difficult corners.
You should never sand perpendicular or at an angle to the grain. The wood will splinter and smear the normally distinct grain lines. This may result in a less attractive finished piece, especially apparent after staining.
Sanding wood can definitely be a tall task with some common errors to trip you up along the way. But I’d say if you know the process, and are aware of what you’re doing, it shouldn’t be a real issue for you. Understanding woodgrain, the different methods of sanding, and when to stop are the main lessons I’ve taken from my wand repair studies. Hopefully they will help you help you like they helped my lovely child!