Blasting Abrasives

When looking for the right blasting abrasive for your project it is important that you find the right grain for your application.  You may want an abrasive that has a maximum amount of  hardness for the material you are working with to cut faster and give you a higher production rate which will then allow you to cut your abrasive cost.   Or you may want a milder abrasive for your more delicate work.

Here is a list of different grains and their qualities and applications

Aluminum Oxide Aluminum Oxide has superb physical properties which make for faster cutting and surface smoothing; shorter work cycles and increased production.   It can be used for almost any blasting abrasive application such as marble, glass, granite and ceramic and can be used over and over again.   It falls very high on the MHO hardness scale.  It can also be used to prep surfaces before painting and bonding
Sodium Bicarbonate As this is a food grade abrasive it is excellent for many commercial applications where a biodegradable abrasive must be used such as food processing equipment.  Although it is water soluble it has excellent degreasing properties and  is great for removing grease and oil.  Other applications include graffiti removal and fire and mold restoration work.  It is best used with a wet blaster and cannot be used over again.
Garnet Almandine Garnet is the most widely used Garnet around the world. Its by far the heaviest and most resilient garnet available.   Garnet cuts fast, has low consumption, low dusting and can often be used 3 to 5 times which keeps production cost down.  It can withstand higher cutting speeds and has lower dust levels. Garnet also works well in water jet cutting applications.
Corncob Corn cob abrasive blasting grit is great when working with delicate parts.  It is also the preferred grit for log homes and other wood surfaces.   Corn cob grit will remove surface contamination, debris and coatings without hurting the materials surface. It’s great for polishing many different types of plastics.  It is virtually dust free, resistant to break down and can be used many times.

Emery Emery is an ore that is rich in aluminum oxide and is a natural composition of corundum and iron oxide.  Emery is a very dense, non-porous fine-grained aggregate.   It’s mainly used in buffing compounds, mostly for chrome plate, as a loose abrasive in ball grinders and as a tough additive for anti-skid flooring applications.  Some applications include concrete non-skid surfaces in conjunction with concrete or epoxy resins, barrel finishing, pressure blasting, coated abrasives, tumbling and deburring media, lens grinding and lapidary work.

Glass beads blasting can be used on a wide range of materials including metal, glass, plastic and rubber. Glass Bead blasting removes burrs, feathered edges, from parts in a precision operation.  Glass Bead blasting guarantees that no base metal from the surface is removed. One of the benefits of Glass beading is that it produces no change to the metal surface and no embedding of contaminates or residue left on the metal surface, unlike other cleaning and finishing methods.
Silicon Carbide
Walnut Shells
Steel Shot/Grit
Plastic Media

Industrial Abrasives

Abrasives are materials having a comparatively higher hardness and are used to shape other materials by grinding or abrasive action. These materials are used as loose grains, as grinding wheels, or as coated abrasives, coated on either cloth or paper (sandpaper being the most common example).

Abrasive products find a wide range of application in the industries including, but not limited to, grinding and polishing glass, cleaning and machining metals, cutting metals, glass, cement etc., grinding logs for paper pulp. Abrasives are also used to manufacture products like brake lining, non-slip flooring required in certain conditions, etc.

Abrasives are harder than the material that it is used to polish and this difference in hardness is what makes the abrasives work. Traditionally, various minerals were used as abrasives, typically those having hardness of 7 or more, on the Moh’s Scale of Hardness. Nowadays, many synthetic stones and other materials prepared artificially are used as abrasives in various applications. Diamond is a commonly used abrasive in various industrial applications, due to its high level of hardness. Various minerals that are used as abrasives are either crushed, or are already found in the powdered from, the grain size of which ranges from 1m to 2mm (1000micron=1mm).

Factors deciding how quickly a substance is abraded include:
Relative difference in hardness between two substances.
Grain size and its matrix- larger grains will cut faster as well as deeper.
The force at contact- more force will obviously mean more abrasion.
Type of lubricant or a coolant used.

Some of the naturally occurring abrasives are Calcite, Emery, Novaculite, Pumice, Rouge, and Sand. Some like Diamond and Zirconia Alumina are found in nature, but are also extensively manufactured synthetically. Other artificially prepared abrasives commonly used in industries are Borazon, Ceramic, Corundum, Dry Ice, Glass Powder, and Silicon Carbide.

While natural abrasives are often sold as dressed stones in the form of blocks, both naturally occurring as well as synthetic, abrasives are available in variety of shapes and sizes according to different use. These are usually bonded or coated abrasives, which includes blocks, belts, discs, wheels, sheets, rods, and loose grains. Grinding wheels are a type of abrasives that find a wide range of industrial applications, right from cutting, sharpening to shaping materials. Previously, such wheels used human power in the form of pedal or human operated cranks. However, now these comfortably work with the help of an electric motor. The high speed of motion imparted by such motors has necessitated the use of a coolant fuel for lowering of the resultant heat produced. However, many researchers suggest that such coolants or lubricants are more important to reduce the tensile stresses acting on the wheel.

The type of abrasive to be used for a particular work will be governed by the size, shape and the nature of the work piece, as well as the type of finishing desired.