Specialty abrasive grain and finishing media include glass beads, sodium carbonate, walnut shells, corn cobs, sponge, hardwood, coal slag and other organic materials as well as other unique compositions or materials for specialized processing. Specialty abrasive grain and finishing media are softer than metal abrasives and metal media, or ceramic abrasives and ceramic media. Products vary by application, type, shape, media size, and grit grade or shot size. There are three main grading systems for specialty abrasive grain and finishing media. Mesh-graded products use mesh size, which is determined by the number wires per unit length. Micron-graded products consist of very fine abrasive grains that are graded to micron-size ranges. SAE abrasive grains meet grit standards from the Society of Automotive Engineers (SAE).
Types of Specialty Abrasive Grain and Finishing Media
There are many different types of specialty abrasive grain and finishing media. Choices include carbonate, corn cobs, glass, hardwood, slag and coal slag, sponge and foam, organic materials, walnut shells, and wheat starch. Sodium carbonate (baking soda) and calcium carbonate (chalk and limestone) are commonly available materials. Corn cob is a very soft, low-aggressive media for stripping coatings from soft metal, wood, plastic, or composite materials. Glass abrasive grains and finishing media have very sharp edges. Hardwood abrasives are often made of oak or beech. Organic abrasives and organic media is a broad category of specialty abrasive grain and finishing media that includes not only corn cobs and hardwoods, but also fruit pits and nut shells.
Specialty abrasive grain and finishing media includes nut shells from walnuts, pecans, and coconuts. Wheat starch is another type of organic product. Typically, this type of specialty abrasive grain and finishing media is used for blasting or coating removal. Slag, coal slag, and aggregate media are also available. Slag is a non-metallic byproduct of smelting, a chemical reduction process that produces a metal from its ore.
Typically, specialty abrasives and specialty finishing media are used in cleaning, finishing, and surface-preparation applications with products that would be damaged by other, harder media types. For example, specialty abrasive grain and finishing media is used to remove paint from wooden furniture without abrading the wood’s surface. Plastic parts are also mass-finished using wooden pegs or other specialty abrasive grain and finishing media that remove flash without abrading or marring the soft plastic surfaces. Other applications for specialty abrasive grain and finishing media include abrasive jet cutting, blasting, blending and intermediate cutting, burnishing, deburring and deflashing, descaling and stripping, fast cutting, grinding and ball milling, peening, polishing, and tumbling and mass finishing.