What Are Abrasives And What Are They For?

Abrasives are used as elements in the different tools that exist for professional or DIY jobs. For example, there are the discs for sanders or polishers. However, before choosing a sandpaper or disc you should check the size of the grain to see if it will serve you in the work you want to do.

Many people wonder what an abrasive material is. Well, it is a substance, either synthetic or natural, that is used to perform different tasks, among which we can mention milling, sanding, polishing, grinding or cleaning a solid material. In addition, they are often used in both artisanal and industrial processes, for example, in the automotive, construction and carpentry industries.

Classification of abrasives

There are two types of abrasives, artificial or industrial and natural . Find out more about them below.

Industrial or artificial abrasives are those that are obtained by chemical or thermal action of raw materials or metals. Among the industrial or artificial abrasives we have Silicon Carbide, Aluminum Oxide, Cubic Boron Nitride and synthetic diamond. Instead, natural abrasives are those that are extracted from nature, for example, diamond, sandstone and quartz. You must bear in mind that this type of abrasive is not recommended to be used raw, since it does not achieve quality finishes.

Power tools and abrasive discs

In the market there is a wide range of power tools including grinders, circular saws, grinders and sanders, the latter are widely used for DIY and carpentry work. In addition, there is a wide variety of models, among which the belt sander stands out.

Also, we mentioned that there is the abrasive disc, which is a self-sharpening tool made up of abrasive grains, that is, cutting material. This disc is joined by a binding agent and in turn reinforced by a mesh that provides it with a certain space known as pores between each of the cutting edges.

Main types of abrasive grain

Both the cutting disc and the grinding disc are composed of different types of grain, which are classified into two large subgroups:

  • Conventional abrasive discs :  These are discs whose abrasive grains consist of a mixture of zirconium and aluminum oxides. These are used in semi-hard, hard or soft materials.
  • Super-abrasive discs: It has boron nitride or polycrystalline diamond as a cutting material They are used for the roughing or cutting at high precision and speed of very hard materials.

Abrasive grain size

Abrasive grain size is indicated in terms of mesh, for example, finer grains are represented by high numbers, while coarse grains are represented by lower mesh numbers. Next, in the following table you will see the size of the different types of grain.

Grain type Size
Very fine grain 240 – 280 – 320 – 400 – 500 – 600 to 2500
Fine-grained 80 – 90 – 100 – 120 – 150 – 180 – 200
Coarse-grained 8 – 10 – 12 – 14 – 16 – 18 – 20 – 24
Normal grain 30 – 36 – 40 – 54 – 60 – 70

Types of discs for DIY

To carry out your DIY work, you will find different discs on the market that will help you successfully complete your task, for example, there are discs for polishing paint, wood, metal, glass, among others. We also have sanding discs and, among them, the most prominent are fiber, these will serve you for very heavy jobs where you have to remove a lot of material. Likewise, there are the microfine discs commonly used in the removal of imperfections in automotive paints.

Also, we mention the Flap discs, which are used for finishes and when performing jobs that merit changing discs. In the same way, there are the feather discs, made of velcro; They are very useful for finishing on different surfaces and you can use them in rotary- orbital sanders .

On the other hand, there are polishing discs, which can be designed to finish different specific materials. Thus, there are discs for polishing stainless steel, resins and more, which are used in the miter or stationary saw.

What are sandpaper and which ones exist?

Sandpaper are coated abrasives and are made up of a layer of abrasive particles on a material whose backing is flexible. In addition, the abrasive particles are attached to the support (in many cases “thick paper”) by an abrasive product. There are different types of sandpaper, among which we can mention:

  • Aluminum oxide sandpaper : They are characterized by being the most durable and popular, as they are commonly used to sand wood or metal.
  • Silicon carbide sandpaper: These sandpaper are very suitable for sanding very hard materials such as glass, stone, marble, among others.

Abrasive applications

Abrasive products are common both among tools in a workshop and in the home. Among the main uses we can mention drilling, cutting, smoothing and grinding different types of materials such as plastic, steel, fiberglass, wood, etc. In the next section, we will indicate the uses of the most common abrasives.

  • Polished: Allows a surface to look shiny and beautiful, for this it is necessary to use polishing discs. This is a process that is carried out many times in the automotive industry.
  • Cutting wheels: They are used to cut steel, mainly, in circular table saws and manual angle grinders.
  • Sharpening: Used to finish cutting blades, for example knives.
  • Drilling: In this case, bits made with diamond are used, which are used for mineral and oil exploration.
  • Sanding: They are used in order to smooth surfaces, this is very important for carpenters, since they do not want their work to be left with thick surfaces or chips. To do this, carpenters have to grind the wood until the surface is smooth and soft to the touch.

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