How to choose a suitable blast media for abrasive blasting
In selecting a specific media it is helpful to understand some of the materials used and how they compare. Blast media can be made of natural material such as silica, sand, mineral sand, flint, garnet, zircon, and other mineral products. It can be made of some natural byproducts such as walnut shell or corncob. And it can be manufactured of a variety of metal and non-metal compositions such as steel, iron, aluminum oxide, silicon carbide, plastic, wheat starch, and glass bead.
In selecting a media, the comparative features that are the most important size of the product, how well it will cut, how well it will recycle and how much it cost.
It is also important to know if there are any health and safety issues, such as lung problems associated with silica, and if the media will leave by-products on the surface, such as oils from walnut shells. Iit is a good idea to test different media to have a visual idea of the effect that they will have on the part.
Hard grit media such as aluminum oxide will cut faster and deeper than soft, angular media such as plastic or agricultural grit. Mineral, ceramic, or metallic grit media are used in air-blast systems. Iron and steel media are more often used in turbine-blast equipment. Materials that are more prone to fracture, reflected in the chart by friability, are not good materials for recycling. Recirculation of thesematerials will produce wide variations in the surface condition.