How to choose the best blasting abrasive

Each abrasive has a profile of hardness, shape, recyclability and cost that makes it more or less suitable for the job. These are the main ones:

Steel abrasive (carbon or stainless)

• Produced from steel by melting with controlled composition: spherical particles (shot) which, on fracturing, yield the angular form (grit).
• On blast wheels, shot, grit or a mix are used; when replacing sand, almost always grit.
• Highly recyclable: 700 to 5,000 times depending on diameter, type and hardness. It does not contaminate (quenched-and-tempered steel) and needs no drying.

Glass beads

• For surface preparation and cleaning, decorative finishes, etching and shot peening.
• Removes no base metal and leaves no embedment: achieves a fine, clean finish.
• Suitable when the part must not be contaminated or dimensionally altered (stainless steel, non-ferrous).

Aluminum oxide (alumina)

• Synthetic mineral (Al₂O₃) made from bauxite; the brown grade has at least 95% Al₂O₃.
• High hardness and sharp edges → an aggressive abrasive, ideal for demanding descaling.
• Recyclable 10 to 40 times depending on use and material.

Garnet (almandine)

• Natural silicate mineral, chemically inert, with no quartz or toxic components (an advantage over sand).
• Hardness and shape that make it aggressive; widely used in sandblasting.
• Recyclable up to about 5 times.

Slag

• By-product of metallurgical melting or combustion (copper, nickel, coal, blast-furnace slag).
• Very sharp edges but high fragility → not recyclable, high consumption per m².
• A low initial-cost option for single-use abrasive descaling.

Silica sand

• The historical abrasive (it gives sandblasting its name); silica is used, never calcareous.
• Very fragile: single use (over 80% turns to dust on the first impact), generating heavy pollution.
• Releases free silica, the cause of silicosis: banned or restricted in most advanced countries.