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What are the Different Types of Abrasives?

published on 11/09/2023

The world of abrasives is vast and diverse, encompassing a variety of materials and tools with both industrial and craft applications. Whether to remove imperfections, prepare a surface for painting, or give the finishing touch to a project, it’s important to choose the right type of abrasive to achieve the desired results.

With so many types of abrasives to choose from, how can you be sure you’re making the right choice? Our abrasive blasting experts have created a comprehensive guide to the different types of abrasives, explaining their characteristics and how to choose the right one for your project.

How do abrasives work?

To understand how abrasives work, it’s essential to look at their key components:

Backing: The backing is the material that the abrasive is attached to so that it can be handled and used. Backing can be made from paper, cloth or vulcanized fiber. The choice of backing material will depend on the type of abrasive and what it will be used for.
Binder: The binder is what adheres the grain to the backing. It will determine how much stress the abrasive tool can withstand. A binder makes it possible to spread and adhere the grain to the backing evenly.
Surface binder: Once the abrasive has been fixed to the backing by the base binder, a surface binder is often added. This protects the grain and reinforces the bond, improving the durability and efficiency of the abrasive tool.
Abrasive grain: This is the active element of the tool. Depending on the type of grain, the properties and applications of the abrasive tool will vary. There are abrasive tools adapted to every situation.

Abrasive backings

Every type of abrasive is unique, in part due to the backing. The choice of backing determines the flexibility, durability and overall performance of the abrasive tool. The following are the main backing materials for abrasives.

Paper

Paper is one of the most commonly used backing materials for abrasives, especially for manual applications. Paper is light, flexible and adaptable. It is generally classified according to weight, with papers ranging from 70 to 100 g/m² for common abrasives, and heavier papers for abrasive belts used in machines.

Paper offers excellent adhesion for the abrasive grain. It is commonly used in the woodworking and craft industries, for applications in carpentry, painting, varnishing and welding. However, paper’s fragility makes it less suitable for abrasives used in the metalworking industry.

Cloth

Cloth is a resilient abrasive medium that offers greater resistance to tearing than paper. Because cloth is strong, cloth-based abrasives last longer even when exposed to high stress.

In addition, cloth backings can bend without breaking, which is an advantage for work that involves using an abrasive on complex contours or shapes. For this reason, cloth-based abrasives are especially useful for metalworking, where durability and flexibility are essential. Cloth-backed abrasives work well on materials such as steel, stainless steel and other metals.

Vulcanized fiber

Vulcanized fiber is a composite material made mainly from paper, which is both rigid and strong. It is water-resistant and stable, making it a preferred choice for many abrasive tools, including discs, belts and sheets.

Vulcanized fibre backings are ideal for applications requiring constant force, such as stripping or smoothing rough surfaces. Vulcanized-fiber abrasives can also be used in wet conditions, making them versatile and suitable for a variety of projects.

Abrasive binders: what makes abrasives strong

Binders are used to stick different types of abrasives to a backing and make them strong. They also affect an abrasive’s resistance, its ability to be used at different speeds and temperatures, and how long the abrasive will last.

Types of binders

Resinoids: These binders are manufactured from synthetic resins and are often used in adhering abrasives to grinding discs and flat cutting discs. Thanks to their flexibility, resin bonds offer excellent impact resistance, which makes them suitable for high-speed grinding applications.
Metal binder: This type of bond is mainly used for super-hard abrasives, such as diamond and cubic boron nitride. The high thermal conductivity of metal binders enables rapid heat dissipation, making them ideal for high-temperature operations.
Rubber binder: Rubber binders are flexible and offer an excellent surface finish. They are commonly used in polishing and finishing wheels, as they reduce vibrations.
Lacquer: These binders are formed using a lacquer as a medium. They are generally used in coated abrasives, such as sheets and rollers. Their main advantage is their ability to form a close bond with the grain, guaranteeing a smooth finish.
Silicate: Silicate bonds are mainly used in the creation of bonded abrasives for low-speed grinding applications.

Abrasive grains

Each type of abrasive has its own properties and level of hardness. Different types of abrasive grains are required for different projects to ensure optimal sanding, polishing or industrial plant cleaning.

Aluminium oxide (Corundum)

White corundum: Made from pure aluminum oxide, offers high hardness and heat resistance. Ideal for cutting metals and finishing stainless steel.
Pink corundum: Recommended mainly for wood sanding, especially for jobs such as parquet sanding.
Brown corundum: Widely used to add texture to a surface or prepare it for painting. Recommended for use in preparing surfaces for industrial paint jobs.

Silicon carbide

Properties: Exceptionally hard, works in both wet and dry conditions. Silicon carbide is a cutting abrasive, but is a less durable variety, especially when used on hard surfaces.
Applications: Recommended for softer materials such as plastics, glass and marble, or for removing lacquers and varnishes. Since it can be used in wet conditions, silicon carbide is perfect for finishing stone and marble.

Zirconium oxide and ceramic

Features: Zirconium oxide is known for its toughness, particularly its resistance to heat. It is often used on hard-to-sand materials such as stainless steel and steel. Ceramic, on the other hand, is highly durable thanks to its micro-crystalline structure.
Advantages: Zirconium oxide can be used to rapidly remove stock, making it ideal for roughing work on hard materials. Ceramic is optimal for prolonged use on materials such as aluminum and mild steels, as it is very durable.

Types of abrasives

Aside from their composition and properties, different types of abrasives can be found in a variety of formats to meet specific needs and applications.

Abrasive sheets

Uses: Sanding sheets are versatile. They can be used manually for delicate work, or attached to sanding blocks for better grip and uniform pressure. Perfect for small areas or irregular shapes, they are the tool of choice for fine detail or finishing.
Advantages: Easy to handle and cut, abrasive sheets are highly accessible to the occasional DIYer and can be changed quickly as needed. They can easily adapt to the shape of objects, guaranteeing uniform sanding.

Sanding discs

Adaptation and compatibility: Sanding discs are specially designed for mounting on orbital sanders. Choose a disc type to fit the machine being used, to be sure that it can be attached securely and will rotate correctly.
Advantages: Discs offer a larger work surface than sheets, making them ideal for sanding large surfaces. The rotary movement of the machine guarantees fast, efficient sanding, whether for roughing or finishing work. In addition, they are often easy to change since they rely on fastening systems like Velcro.

Sanding belts

Applications: These long belts are specifically designed for belt sanders, which sand large surfaces quickly. They are commonly used on flat surfaces such as floors, large tables or panels.
Power: Belt sanders are powerful, so material can be removed quickly and efficiently. Ideal for stripping, levelling or coarse sanding, these belts guarantee fast, even results over large areas.

Abrasives for industrial cleaning

Baking soda: Gentle and effective, soda blasting relies on baking soda to delicately clean fragile surfaces, without the risk of damaging them.
Sand: Historically one of the first materials used for sandblasting, sand is an economical option for removing rust, paint and dirt from a variety of surfaces.
Steel shot: This type of abrasive is mainly used for cleaning metal parts. Steel shot can easily remove rust, scale and old paint layers.
Glass beads: These small particles provide a smooth finish after cleaning. They are particularly suitable for delicately stripping or polishing specific types of surfaces.

Importance of grit size for sanding

The last element that defines a type of abrasive is its grain. This is a very important factor, because the right grain size plays a huge role in obtaining optimal results.

Grains are measured and categorized according to grit size (grain size). In precise terms, grain size indicates the number of openings that the grains can pass through, per linear inch in a sieve. For example, a size 20 grain will fit through a 20-mesh sieve, that is, a screen with 20 openings per linear inch.

Coarse to medium grits (60 to 80)

Roughing: Due to their large size, these grits remove material quickly, making them ideal for correcting major defects and smoothing uneven surfaces. This is the grain of choice for removing old paint and thick varnish or for shaping tough materials.
Rough surfaces: These grits leave visible streaks on the material, often requiring subsequent sanding with finer grains to obtain a smooth surface.

Medium grits (80 to 100)

Semi-finishing: Ideal for surface preparation after roughing, these grains effectively remove the marks left by coarser grits. They are also ideal for minor adjustments and for preparing a surface before applying paint or varnish.
Delicate surfaces: When grinding soft materials or surfaces that require only light grinding, these grains are a good choice as they offer a balance between stock removal and finishing.

Fine to ultra fine grits (100 to 600+)

Finishing: When the surface has already been prepared and it’s time to make a smooth, uniform finish, fine grit is the ideal choice. Fine grains eliminate the last remaining irregularities on a surface and perfectly prepare a surface for subsequent finishing.
High-finish: Extra-fine grains are often used for precision work, such as polishing varnished surfaces, preparing car bodies for painting, or grinding wood finishes. Their fineness guarantees a mirror-like finish, with no perceptible scratches or marks.

Trexo: abrasive blasting experts

In the world of abrasives, every detail counts: the type of grit, the backing, the bond and even the way the abrasive is used. It’s vital to make an informed choice, as the type of abrasive affects the quality of the finish, the strength and resistance of tools and even the safety of the user. This is where Trexo comes in.

The experts at our industrial cleaning company don’t just know about the different types of abrasives. We have also mastered the art of keeping them in perfect working condition. When performed correctly, abrasive cleaning is a specialized type of industrial cleaning that can significantly extend the life of your tools and guarantee consistent performance.