Abrasive belts are helpful for sanding, grinding, deburring, blending, and finishing metal, wood and other materials. These belts are used with belt sanders and grinders to shape a workpiece, clean surfaces, or provide a fine finish. Belts are constructed as either coated or non-woven, and have gritty, abrasive particles varying in both size and number in a given area, depending on the desired result.
When selecting abrasive belts, there are several things to consider. The first is grit size, or grit number, which indicates the size of the abrasive grain particles adhering to the belt's backing. With a lower grit size like 40, there are fewer and larger grains in a given area, making it "coarse" and commonly chosen for removing excess material and shaping a workpiece. With a high grit size like 400, there are more and smaller grains in a given area, making it "fine" and creating a smooth surface finish.
Also consider grit material. Aluminum oxide is the most common abrasive material, chosen because it is durable and compatible with many different materials. Zirconia alumina is chosen for its fast cut rate and self-sharpening ability, and is most commonly used on metal and wood. Silicon carbide is more aggressive and cuts faster than aluminum oxide. Each grit material has different attributes, like brittleness and hardness. For example, the brittle particles of zirconia alumina break under the heat and pressure of use, creating new sharp edges. Hard grit materials, like silicon carbide, are useful for removing rust, grinding masonry, and other rough work.
Another important factor is how the belt is constructed: non-woven or coated. Non-woven abrasive belts have abrasive grains that are held in a flexible nylon web, and are most often used in finishing applications. Coated abrasive belts use an adhesive to attach the abrasive grains to a backing. The backing may be paper, cloth, or plastic film. In general, a paper backing is more flexible and offers a more consistent finish than a cloth backing. Cloth backing is sturdier than a paper backing and resists tearing while bending and flexing during use. Plastic film backing has a more consistent thickness than paper and is used for micro-finishing applications.