Grit Blasting / Surface Preparation

Grit blasting (also called sand blasting or abrasive blasting) is the process of cleaning, roughening, or finishing surfaces by propelling abrasive particles (sand, steel grit, glass beads) at high velocity using compressed air. Used in Indian construction for: (1) Surface preparation of steel before painting (removes mill scale, rust, contamination); (2) Concrete surface preparation for bonding; (3) Architectural finishing of stone and concrete; (4) Cleaning of corroded or damaged structures during repair. Per IS 1182:1983 + IS 6005:1998, grit blasting is graded by surface preparation level (SA 1, SA 2, SA 2.5, SA 3 — increasing cleanliness).

For steel surface preparation: SA 2.5 (commercial blast cleaning) is the typical specification — removes 95%+ of mill scale and rust, exposes clean metal. Used before primer + paint application. Cost: ₹150-400/m² depending on area and access. Major Indian contractors specialise in surface-preparation services. Equipment: portable compressors (200-400 cfm) + grit-blasting nozzles + recovery systems for environmental compliance. The most-overlooked aspect: dust and silica exposure — grit blasting generates significant dust (sand contains silica, hazardous to lungs); modern Indian practice uses dust-suppression spray, vacuum systems, or alternative blast media (steel grit, glass beads) to manage exposure.