Building & renovation

How much abrasive do you need for sandblasting?

How many kg and bags of abrasive for sandblasting — from surface area, consumption per m² and bag size.

Quick answer

Abrasive is sold by the bag, but jobs are priced by m². Consumption on steel at 6–7 bar with a #5 nozzle is typically 8–12 kg/m² for paint removal — light rust can be ~6, heavy mill scale ~18. Formula: total kg = area × kg/m² × (1 + loss%). Worked example: 15 m² fence panels, 10 kg/m², 15% loss → 15×10×1.15 = **172.5 kg** → **7× 25 kg bags**.

Advanced settings

Bags to buy

7

Abrasive needed
173 kg
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Consumption depends on nozzle size, pressure, media type and operator skill. Garnet and aluminium oxide at ~6–7 bar typically use 8–12 kg/m² for paint on steel. Add loss for dust collection and spillage — recycle systems lower net use.

How it works

Recycle cabinets reuse grit and cut net consumption 30–50%; open-blast outdoors loses more to dust and spillage. Garnet cuts faster than slag but costs more per kg — the calculator only sizes quantity; media choice is a separate decision. Always use proper sandblasting respirator and containment.

Frequently asked questions

How many kg per m² for rust on steel?+

Light surface rust: ~5–8 kg/m². Medium paint + rust: ~10–12 kg/m² at 6–7 bar. Heavy scale or thick coatings: 15–20+ kg/m². Pressure, nozzle size and standoff distance change these numbers more than the metal grade.

25 kg bag — how many m² does it cover?+

At 10 kg/m² with 15% loss, one 25 kg bag covers roughly 2.2 m² (25 ÷ 11.5). At lighter 6 kg/m² rust work, about 3.6 m². Always round up — running out mid-job means downtime and moisture flash-rust.

Does recycled grit use less abrasive?+

Yes — cabinet systems recover and reuse media until it breaks down. Net new abrasive per m² can drop 30–50% versus open blast. Factor higher loss % (20–25%) for outdoor open blasting without recovery.

Garnet vs aluminium oxide consumption?+

Similar kg/m² at the same pressure, but garnet often finishes faster (fewer passes) so total time drops. Aluminium oxide is harder and lasts more recycle cycles in a cabinet. Enter your measured kg/m² from a test patch on scrap.

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