Copper Slag vs Garnet vs Steel Shot vs Abrasive Grit

The best blasting abrasive depends on one question: can you recover and reuse it? For open, outdoor blasting where the abrasive is lost, copper slag gives the lowest cost per square metre. For enclosed blast rooms and machines with recovery, steel shot and steel grit are cheaper over time. Garnet sits between the two and is the choice for low dust and fine finishes.

The four abrasives at a glance

• Copper slag: mineral smelter by-product, 6 to 7 Mohs, angular, single use, moderate dust, rough anchor profile, lowest cost per tonne. Best for open site blasting.

• Garnet sand: natural mineral, 7.5 to 8 Mohs, sub-angular, reusable 3 to 5 times, low dust, clean uniform profile, medium to high cost. Best for open or enclosed blasting and waterjet cutting.

• Steel shot: metallic, round, 40 to 51 HRC, reusable for hundreds of cycles, very low dust, smooth peened finish, high cost per tonne. Best for wheel-blast machines and blast rooms.

• Abrasive grit: metallic, angular, 40 to 65 HRC, reusable for hundreds of cycles, very low dust, sharp etched profile, high cost per tonne. Best for blast rooms and machines.

When to choose copper slag

Choose copper slag for outdoor and site work where the abrasive cannot be collected: structural steel, tanks, pipelines, bridges, ship hulls and plant shutdown jobs. It reaches Sa 2.5 quickly and its low price keeps the cost per square metre down even though it is used once.

When to choose garnet sand

Choose garnet where dust must stay low, where the steel is thin or the finish must be uniform, or where the specification bans slag abrasives. It can be recycled a few times, which offsets part of its higher price. Garnet is also the standard abrasive for waterjet cutting.

When to choose steel shot

Choose steel shot for wheel-blast machines and enclosed rooms with recovery systems. The round particles clean and peen the surface, which suits castings, forgings, springs and plate descaling. It leaves a smooth, dimpled finish rather than a sharp profile.

When to choose abrasive grit

Choose angular grit when you need a sharp anchor profile for heavy-duty coatings and you have a recovery system. Many blast rooms run a mix of shot and grit to balance cleaning speed and profile depth.

A quick way to decide

• Abrasive is lost after blasting: copper slag.

• Abrasive is lost, but dust or finish is critical: garnet sand.

• Abrasive is recovered and you need a smooth, peened finish: steel shot.

• Abrasive is recovered and you need a deep profile for coating: abrasive grit.

One supplier for all four

V K Corporation stocks copper slag, garnet sand, steel shots and abrasive grit, and delivers on its own trucks across Jharkhand, West Bengal and Odisha, with pan-India dispatch. See the full range on our Products page, or call +91 9234 222 746 for advice on the right abrasive for your job.