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Technical Library

ABRASIVE MATERIAL TYPES

The most popular materials to use as abrasives are:

Aluminum Oxide (A/O) – Popular synthetic material. Aluminum Oxide is an industry standard for ‘common’ applications. A/O is excellent for planning, stripping, roughing, and finishing on all wood. It is also great for snagging, weld removal, and grinding of all types of metals. High Quality Aluminum Oxide is highly friable. Meaning that as the material is used, the tips of the grains fragment, continually providing sharp cutting surfaces, which increases its working life. Aluminum Oxide abrasives are highly customizable to specific applications. 

 

Silicon Carbide (S/C) – A popular synthetic material among wood finishers and metal finishers alike. Silicon Carbide is used for sanding finishes, as it is provides even cutting. Silicon Carbide is harder and tougher than Aluminum Oxide. It is preferred in certain applications that require waterproof materials. Most often used in the automotive industry, silicon carbide is preferred for automotive paint preparation. S/C is also used on marble, garnet, glass and other solid surface materials. It is black in Color.

 

Ceramic – Ceramic, a premium product, is an extremely hard material. Ceramic abrasives provide long lasting and aggressive cutting of metals. It was developed to provide a longer life and more even cuts than Zirconia based materials. Ceramic is friable and continuously provides a sharp cutting surface that increases the life of the product. It is usually yellow to orange/red in Color.

 

Zirconia or Alumina Zirconia (A/Z) - Known as “2 steps away from the hardness of diamond”, Zirconia and Zirconia/Alumina are used for fast hard wood removal in woodworking and heavy metal grinding and polishing of metals. Most metal-working users utilize Zirconia based products due to the extended life of zirconia and the aggressive cutting ability. Zirconia belts do not typically exceed 220 grit. It is blue to green in color.

Non-Woven - Non-woven materials are made from a variety of materials and are not typically measured in grits. Often, products made from non-woven materials are used for buffing and polishing metals, deburring, cleaning, rust and grime removal. Non-Woven abrasives are waterproof and durable. They are also used as an alternative to steel wool. They come in various colors.

Other materials are flint, Garnet and Emery. These are used in light applications and for those interested in 'natural' products.

ABRASIVE MATERIAL BACKINGS:

Paper – Paper backed sandpaper is used for aluminum oxide and silicon carbide belts, discs, and shop rolls. Paper has advantages such as light weight and cheaper backings that provide even cutting for delicate processes and in finer grits. However, it does not provide the rugged characteristics of cloth or synthetic backings.

Paper backings can also be infused with other materials, such as latex. This allows for a very flexible and durable product that provides consistent scratch patterns. 

Cloth (cotton, polyester / poly-cotton) Cloth is a popular backing due to its relative cost effectiveness and strength. Premium sandpaper products usually feature cloth or other synthetic backings. Polyester is a synthetic backing that offers superior strength, toughness, and is waterproof. Most standard sized belts are cloth backed. Some industrial and professional users utilize paper wide belts for specific woodworking, stone, granite, plastics and metal finishing applications.

Plastic/Film - Plastic film backing is excellent when users demand the best in uniform sanding. It is popular in wet sanding due to its waterproof properties, strength, and flexibility.

Foam and Sponge - Foam and sponge backings are best for hand sanding moldings and veneers. These materials form fit contours and are an excellent choice when flexibility is required.

WEIGHT:

Coated abrasive products are categorized by the ‘weight’ (wgt) of the backing material used. This alphabetical system designates the thickness of the backing. Below is a list of commonly used weights:

Paper – A (lightest) – F (Heaviest)

A&B wgt are common in low-end materials and/or finer grits. They are used for hand sanding applications. C&D wgt is the most popular and are made with heavier backings. E &F wgt are most commonly used for belts and discs.

Cloth – J (lightest), X, Y, YY (Heaviest)

Depending on the application, a good ratio of weight, flexibility and flatness are crucial for long lasting abrasive products. J wgt material is the lightest and most flexible. This is popular in light metal finishing applications. X wgt has the widest range of applications. Y wgt is used for heavy duty applications. Cloth materials are the stiffest and used in most belt sanding applications, because of its increased strength. Paper backing is used when uniform consistency is needed. Paper backed materials are used in hand sanding applications such as polishing and fine wood finishing.

Other weights (S,T,M) are seldom used, only for specific applications and products.

JOINING:

Abrasives can be joined together to make a continuous belt in a variety of ways. Smaller pump sleeves have the backing glued together while most belts use a combination of tape and glue. Different joining methods produce different results. Some industrial manufacturers require joints that are specific to their operations. Red Label belts are butt tape jointed bi-directional belts, which means they can be run both directions flawlessly. As a manufacturer we do provide a variety of joining types to for applications with specific requirements.

COATING:

Coating refers to the amount of abrasive grain that is applied to the backing material. In general, closed coats provide an even finish on solid materials and open coats provide better finishes on woods.

Closed Coat: Grain is applied evenly together without any voids in the coat. It provides a longer life and finer finish. Typically used in non-woodworking applications

Open Coat: Only a portion of the backing is covered with an abrasive grain. This type of coating reduces loading at courser grits. The backing is covered 50%-70%, which allowing more room for buildup to expel from the grain.

Semi-Open or Semi-Closed: In between closed and open coat.

OTHER TERMS:

Stearated / Non-Stearated - Stearate is a chemical application on the surface of an abrasive product that reduces the adherence ability of materials. The process of sanding creates heat. The heat radiated can be quite significant and can melt the surfaces and particles that are being sanded. Stearate reduces head and buildup by reducing friction.

Loading: Loading is a condition characterized when the spaces between abrasive grains become filled with small particles of the material being sanded.

Waterproof – Certain finishing applications generate massive amounts of heat. Water is sometimes used as a coolant, and requires synthetic waterproof backings. Other applications require the use of water-based compounds when waterproof materials are required.

Grit - Grit refers to the cutting ability of a material. It is measured as the amount of abrasive material per square inch. The US and Europe have different grading scales. As a large percentage of abrasive materials are imported or produced in facilities owned by European companies, it is important to decipher the difference between these scales. The US uses the CAMI (Coated Abrasive Manufacturers Institute - now Unified Abrasives Manufacturers Association) standard while Europe uses the FEPA (Federation of European Producers of Abrasives). European scaling is designated with a 'P', followed by the grit number.