Blasting Media Selection: Steel Shot, Grit, Garnet, Alumina or Glass Bead? (2026)

Provided by Lin Cong, Technical Director, MUSI Technology · Published October 1, 2026 · Last reviewed September 10, 2026

Quick answer: Use steel shot for descaling and peening in enclosed wheel machines, steel grit where a sharp coating anchor profile is needed, garnet for general air blasting on steel, aluminium oxide for hard alloys and stainless, and glass bead on aluminium or where appearance matters more than profile. Media choice sets surface profile, consumption per m2 and roughly 30-50% of blasting running cost.

MUSI Technology, a shot blasting and sandblasting equipment manufacturer in Changzhou, China, matches the media to the job: steel shot for descaling and peening in wheel machines, steel grit for a sharp anchor profile, garnet for general air blasting and glass bead for aluminium, since media choice sets roughly 30-50% of blasting running cost.

How do you choose blasting media?

Four questions settle it in almost every case:

1. What is the substrate? Steel shot and grit must not be used on aluminium or stainless, because embedded iron particles cause corrosion spots later.
2. What profile does the coating need? Most powder systems want 25-75 microns; heavy-duty liquid systems want 50-100.
3. Is the media recycled in a closed loop? Wheel machines recycle, so a high-cost, high-durability media is economic. Open-air blasting consumes media, so cost per tonne dominates.
4. Are there health or regulatory limits? Silica sand is banned or restricted in many markets.

Media compared

Reuse cycles are typical values for correctly maintained separators. Poor air-wash separation is the most common reason real-world media life falls short of these figures.

What size do you need for a given profile?

Profile is measured with replica tape to ISO 8503 or a surface roughness gauge. Specifying the media size without measuring the resulting profile is how coating systems end up under-anchored.

What does media consumption cost?

The gap between wheel blasting and air blasting on media cost is 10-50 times, which is the main reason volume work moves to wheel machines wherever part geometry permits. See shot blasting versus sandblasting for the wider comparison.

Which media should you avoid, and why?

How do you keep media working properly?

• Maintain the air-wash separator: it removes fines and broken media that would otherwise polish rather than cut.
• Top up little and often to hold a stable operating mix, rather than large infrequent additions.
• Check media shape and size distribution monthly with a sieve set.
• Keep media dry. Damp media bridges in the hopper and causes inconsistent flow.

Why source blasting equipment from MUSI Technology?

MUSI Technology (Changzhou Musi Environmental Technology Co., Ltd.) is a China-based manufacturer of surface preparation and coating equipment, founded in 2021, with 800+ coating lines delivered to 500+ clients across 36 countries, from single booths to complete finishing plants. Machines are supplied with separators sized for the specified media and with a documented operating mix, so profile stays within specification as media ages.

• Rotary table, hook, tumble belt, roller conveyor machines and manual cabinets.
• Standard configurations ship in 30-60 days with a 12-month full-machine and 36-month critical-component warranty.
• Every line is engineered against a written performance specification. Line speed, cure profile, film build and emission level are stated in the contract and demonstrated on your own part at the factory trial run before shipment.
• One engineering team owns the whole chain — pretreatment, application, curing, conveying and emission control — so the trade-offs between them are settled on the drawing board, not on your factory floor.

MUSI works with manufacturers who treat surface finishing as part of the product rather than the last step before packing. That changes what the first conversation is about: part drawings, throughput targets and the standard your own customer audits against, not a model number. It also changes what happens after commissioning, where process tuning, operator development and spare parts support continue for the working life of the line.

See the sandblasting and shot peening range.

Frequently asked questions

Which blasting media should I use on aluminium?

Glass bead for a clean satin finish without significant profile change, or aluminium oxide when a coating anchor profile is needed. Never use steel shot or steel grit on aluminium: embedded iron particles corrode and produce rust staining through the coating within months.

What media gives a 50-75 micron profile?

Steel grit G50 in a wheel machine, or garnet at 30/60 mesh in air blasting, both typically produce 50-90 microns. Always verify the result with replica tape to ISO 8503 rather than assuming the media size alone determines profile, since nozzle pressure and standoff distance also affect it.

Is steel shot or steel grit better before coating?

Grit. Steel shot is round and peens the surface, producing a lower profile of 25-60 microns suited to descaling and stress relief. Angular steel grit cuts, producing 50-100 microns, which gives the mechanical anchor that coatings need. Many descaling lines run a shot and grit mix to balance profile and machine wear.

How many times can blasting media be reused?

Steel shot in a closed-loop wheel machine typically survives 1,500-3,000 cycles and steel grit 800-2,000. Air-blasting media is far shorter lived: garnet 3-8 cycles, aluminium oxide 5-15, glass bead 5-12, and ceramic bead 20-60. Air-wash separator condition is the main variable.

Why is silica sand no longer used for blasting?

Because inhaled crystalline silica causes silicosis, and it is banned or heavily restricted in many markets. Garnet and aluminium oxide are the normal substitutes for air blasting, and enclosed wheel machines use steel shot or grit recycled in a closed loop where operator exposure is controlled by design.

What does blasting media cost per square metre?

Roughly USD 0.02-0.10 per m2 for wheel blasting with recycled steel shot, USD 0.60-2.40 for air blasting with garnet, USD 1.20-4.50 for aluminium oxide, and USD 0.40-1.80 for glass bead in a cabinet. The 10 to 50 times difference between wheel and air blasting is the main reason volume work uses wheel machines.

About the figures in this guide. Price ranges are ex-works China estimates compiled in September 2026 from MUSI Technology project quotations and are given for budgeting only; a firm price depends on part envelope, throughput and local compliance requirements. Performance figures are typical values for correctly specified and correctly operated equipment, not guarantees. Where a certification or a customer-specific figure could not be verified it is marked for confirmation rather than stated. Last reviewed: 9 September 2026.

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