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You’d think that sanding was a pretty simple part of woodworking; just pick up a piece of sandpaper and get to work, right? That’s not entirely true as choosing the right sandpaper is just as important as using the right technique.
Typically, when sanding wood to a smooth finish, you would start with sandpaper of a lower grit and work your way up through the grits until you get to a higher grit that is sufficient to leave a smooth finish. Each grit of sandpaper that you use will remove sanding marks left by the preceding grit sandpaper.
If you want to learn what sandpaper to use then there are a couple of things you’ll need to think about. Most importantly is the grit but you’ll also want to think about the material used to make the sandpaper as this will affect its suitability.
In this guide, we’ll be discussing the different types of sandpaper and telling you exactly what you’ll use them for. You’ll be choosing the right type with your eyes closed before you know it.
What Is Sandpaper Grit?
Sandpaper grit refers to the coarseness of a piece of sandpaper and this is detailed by a numerical system. Sandpaper with a higher grit number is typically much finer. For example, something with a 1000 grit would be incredibly fine with very small particles. On the other hand, low grit sandpaper is far more coarse and rough.
You will normally find the sandpaper grit number printed on the back of the sheet. The lowest number is 24 and it can go as high as 1000. That said, it’s very rare that anyone would need to use anything on either extreme of the scale.
What Are The Different Sandpaper Grits And What Are They Used For?
When you are sanding, it is essential to make sure you use sandpaper that is designed for the job at hand. You will normally find that you need to use several different grits for every project so it’s worth having a well-stocked workshop where sandpaper is concerned.
Extra Coarse Grit
The coarsest of all sandpapers range between 24 and 36 and these are incredibly rough and tough. This type of sandpaper is normally used for taking off things like varnish or paint, even those that seem incredibly stubborn.
You might also use extra coarse sandpaper when you’re sanding down an old floor and need something more abrasive. For tough jobs, this is where you’ll want to start.
Coarse Grit
The next level up is coarse sandpaper which you would use when you want to roughly shape wood. It’s also great for removing old finishes as long as they’re coated much more lightly. The numbers for this type of sandpaper are between 40 and 50.
Medium Grit
Medium grit sandpaper falls between numbers 60 and 100 and is ideal for the final shaping of wooden products. However, you can also use it when initially sanding very rough wood and it also does well at removing planing marks.
Fine Grit
Your fine-grit sandpaper is used in the final stages of a project. You will find that most fine sandpapers have a grit number between 120 and 220. For most DIY projects, this would be the last piece of sandpaper you use.
Extra Fine Grit
For some projects, you may need to finish your work with extra fine sandpaper. These are also ideal for smoothing the wood between paint and varnish coats. Grit numbers fall between 240 and 1000 but you’d usually not use anything higher than 400 which is considered to be extremely fine. That said, if you’re looking to polish, then something in the 600 range would be most suitable.
Sandpaper Material Types
As well as thinking about the grit number of your sandpaper, it is also worth considering the material it is made from. You’ll need to think about what material you’re working on, for example, wood or metal as this will tell you a lot about which sandpaper material is best. You will find details on the packaging of what materials the paper is most suited to.
Flint
Flint is a natural material that’s brilliant for removing old finishes such as paint or varnish. It is incredibly durable.
Garnet
Garnet is great when it comes to the fine sanding of wood. However, it is not as durable as other natural grains like flint and so isn’t ideal for tougher jobs.
Zirconia Alumina
Unlike some of the materials we have already discussed, zirconia alumina is not a natural product, but synthetic. This is a very durable type of sandpaper that is perfect for removing burrs from metal as well as tougher primary sanding jobs on wood. What’s amazing about this material is that sanding actually sharpens the particles making the paper last longer.
Emery
Emery is often used when working with metal and it does a fine job of removing corrosion and other imperfections. It’s great for polishing but it’s worth keeping in mind that the particles may be far too sharp to use when sanding wooden products.
Aluminium Oxide
This is another type of synthetic sandpaper material that is incredibly durable and brilliant for polishing metal. That said, you will also find that aluminium oxide works very well when you’re sanding hardwoods.
Silicone Carbide
Silicone carbide is largely accepted as being the most durable man-made abrasive material. What’s great about it is that it can be used with a whole host of materials including metal, hard and softwoods, and even plastic so it’s incredibly versatile.
When Should I Change My Sandpaper?
The sandpaper will only remain effective as long as the grit is intact. As you use the sandpaper, the grit will wear down and eventually need replacing. You will know when this happens as the sandpaper stops performing as well and may become clogged with debris much more easily.
Conclusion
Choosing the right type of sandpaper doesn’t need to be difficult. As long as you select the right coarseness, which is indicated by a grit number, and the right type of material, you shouldn’t have any problems in getting your desired finish.
