This is designed to help explain and identify the components of coated abrasives. Coated abrasives are made up of Grain, Resins or glue and Backings.
Abrasive Grains +
Aluminum Oxide – This wedge-shaped grain is tough (fracture-resistant) and well-suited to grinding hard metals and hardwoods. Available in a range of toughnesses identified by color (brown, white, pink), Aluminum Oxide is the best choice for metal grinding or polishing, and wood sanding.
Silicon Carbide – This very hard and sharp grain is black in color. It fractures with use for fast stock removal. Recommended for grinding and polishing materials such as glass, plastics, ceramics, stone, rubber and non-ferrous metals.
Zirconia Alumina – These blue grains stay sharp as they fracture, which gives them long life. Being both tough and sharp, it is ideal for heavy grinding operations on hard materials, especially in grits between 24 and 120.
Ceramic – This white grain’s multi-fracture characteristic makes it cut cooler even in the most extreme high pressure applications, and in low pressure / high heat applications (grinding metal alloys). Best for heavy stock removal of metals.
Garnet – Although not as hard as synthetic grains, this grain is a very sharp abrasive widely used in furniture and woodworking plants. Since it dulls quickly, it is not well suited for metal working.
Emery – These blocky grains have a good polishing action on most metals, and are used for general maintenance and polishing when stock removal is minimal. Used primarily by hand in sheets and rolls.
Crocus – This ferrous oxide grain is relatively short-lived and is best suited to polishing soft metals.
Abrasive Bonds +
Adhesives bond the abrasive grain to the backing and are applied in two different layers. The first “maker coat” layer bonds the grains to the backing. The second “size coat” provides the final bonding. Open coat products have grain covering about 50% to 70% of the backing. The open structure helps to prevent loading when used on soft materials such as wood or aluminum. Closed coat products have grain on about 90% of the backing. These are best for high stock removal of harder materials and usually produce a more uniform finish.
Glue – This animal hide glue bond has lower heat resistance but better finish.
Resin/Glue – A resin coat applied over a glue coat provides better heat resistance than glue only, and better finishes than resin only.
Resin – These all-resin coats give maximum resistance to heat and grain shedding. This best all-around bond is the most durable.
Waterproof – This special resin bond is suitable for wet grinding and sanding.
Backings +
Paper – Highly specialized papers made to a specific flexibility and strength. “A” weight is light, flexible, and good for hand finishing. “C” and “D” weights are stronger, less flexible, and good for both hand sanding and portable vibrating sanders. “E” weight paper is even stronger, less flexible, and used for roll, belt and disc applications where high tear resistance is required. “F” weight is used for rolls, belts and discs when the highest paper tear resistance is needed.
Cloth – “J” and “F” weights use a light cloth best for finishing and polishing contours when surface uniformity and flexibility are more important than stock removal. “X” weight is a strong cloth backing available in a variety of flexes. It is recommended for belt, drum and disc grinding and polishing when stock removal is important.
Polyester – This “Y” weight material is waterproof, tough, stretch resistant and designed for heavy-duty grinding.
Fiber – Consisting of multiple bonded paper layers, it is tough and strong for drum and disc use. Especially well-suited for high-speed disc grinding with high heat.
Combination – Made by laminating a combination of paper and/or cloth backings, it is used for floor sanding products in very coarse grits and for segmental belts used in the board mill industry.
