If you ever had the experience of working with the wood or seen a carpenter doing its work, then you must know about sandpaper. It is mostly used after cutting the wood to sand all the edges and remove material from the surfaces. Sandpaper is used before applying a finish and between the coats of paints. They are basically coated abrasive, whose one side, made up of paper or cloth, is glued to abrasive material.
It is called sandpaper because the other abrasive side is made of crushed substances like shells or sand, glued to parchment with natural gum. Another similar product is also available on the market, called ‘glass paper.’ As the name suggests, glass paper is a kind of crushed glass. But sandpaper is most commonly used than glass paper.
How to Choose Sandpaper Grit?
There are different types of sandpapers available on the market, and you can get the right one, depending upon the grits, grades, quality of abrasives, backing material, and bonding agents. We can measure it based on its grit size, the number of sharp particles per square inch of sandpaper. The larger grit size leads to more edges and smoother sandpaper. The density of grit is also an important factor to look for when choosing sandpaper. Open coated sandpapers allow the sawdust and other particles to gather in it, as they have gaps between grits. These gaps help avoid interference with sanding. On the other hand, close coated sandpaper doesn’t have these gaps, so there is a lot of interference when sanding.
Choosing the right sandpaper may be confusing when starting your work. This is because different sandpaper grits perform different jobs. Always start with a basic one, and follow the rule of thumb.
In this article, we have put together a brief yet helpful guide that will allow you to choose the right sandpaper according to your work.
Select the Right Size of Sandpaper
Sandpaper is made of either natural or synthetic particles. The particles, also known as grits, are checked through screens, sorted by size, and then bonded to paper, sponge, or cloth type back with an adhesive. This is how an abrasive material is created handily so that you can do it on your own.
When you buy sandpaper, you will see the number as 80-grit, 100-grit, 200-grit. This is the gradation scale on which sandpaper grit is determined. One must keep in mind two very important points when buying sandpaper: if the grit number is higher, the grains will be smaller, and sandpaper grit will be finer. But if the grit number is lower, it will have larger grains and coarser sandpaper.
The small grains on sandpaper are 141 microns in size that is equal to 0.00550 of one inch. But remember that the grading or measuring scale for sandpaper can differ in various countries. In the USA, the scale used for sandpaper is CAMI Scale, whereas, in Europe, it is sized by FEPA and is indicated by the letter ‘P.’ FEPA sizes are not the same as CAMI sizes. But here you can get a comparison of both.
40 grit CAMI Sandpaper = P-36 or P-40 FEPA
80 grit CAMI Sandpaper = P-80 or P-100 FEPA
100 grit CAMI Sandpaper = P-100 or P-120 FEPA
120 grit CAMI Sandpaper = P-120 or P-150 FEPA
220 grit CAMI Sandpaper = P-180 or P-220 FEPA
400 grit CAMI Sandpaper = P-660 or P-800 FEPA
Choosing the Correct Coarseness
Most companies mention the coarseness level on the packaging of the sandpaper to make it easy to choose the right one. There is a wide range of grit sizes, which are similarly effective for doing almost the same sanding work. Their range varies from:
Extra Coarse Sandpaper is in the 24 to 36 grit range. It is a really tough one. This one is basically used for removing paints and varnish, which is almost impossible to remove. It can be used for old floors as well. But remember that this is a tough one, so don’t try it on anything other than the hard stuff, or it might ruin the work for you.
Coarse sandpaper has a grit range between 40 and 50. It is suitable for rough shaping of wood and removal of previous finishes, e.g., light coats of polyurethane.
Medium Coarse Sandpaper srange from 60 to 100 grit. They are used in final shaping, as well as in primary sanding of rough wood and removing planning marks on the wood.
Fine sandpaper is used in the sanding of wood before the final look, as it has a grit range between 120 and 220. This one is most suitable for home-based woodworks.
Extra Fine Sandpaper is used between the step when the wood is being coated with paint and varnish. The grit ranges are 240, 320, and 400, which are considered very fine. Grit-600 is the best one for polishing.
Choosing the Right Grit Material
The density of sandpaper and the type of abrasive material are very important for a successful sanding project. Most companies mention what type of abrasive material is used and what job it can perform best, which clears a lot of confusion. But one should also know about it because sometimes these things are not mentioned on the packaging, and you can get into trouble when buying it. Following are some materials you can find sandpaper in:
Flint is a natural grain used to sand off surface products, such as old paints and varnish. It is well suited for this kind of job.
Emery is another natural grain used in removing corrosion and polishing steel and other such substances. It is not suitable for doing woodwork as it has sharp edges.
Garnet is a natural grain that is softer than flint and emery. So, it will quickly get dull when used on metal. It is suitable for fine sanding of wood.
Zirconia Alumina is a synthetic grit. It is best for grinding the burrs on metal. One can also use it for the initial sanding of wood. It is long-lasting as the grit particles become sharper when used on metal.
Silicon Carbide is the most durable synthetic grid. It can sand a wide range of materials such as hard and softwood, metal, and plastics.
Choosing The Right Tools
Sandpaper is quite a handy tool – you can fold it into palm-size or cut it into a shape that is easier to hold. But choosing the right sandpaper is not enough; you should have the right tools for sanding as well.
These important tools required in sanding includes manual hand sander, sanding sponge, vibrating palm sander, orbital sander, random orbital sander, belt sander, drum sander, beach mounted sanders, and floor sander.
All of them help sand, wood, plastics, and metals. They are unique in their shape; that is why they have unique jobs to perform. All of them are important in the sanding process. But you have to be careful with them, a few of them can be sharp, and you can hurt yourself.
All of these sandpapers and tools mentioned above are available on the market, helping you with all kinds of sanding projects. We hope this article helps you out in your next project and have cleared all your confusion regarding sandpaper grits.