sandblasting

Sandblasting is a surface preparation technique in which abrasive particles are propelled at a surface under high pressure to clean, etch, or texture it. The process removes paint, rust, scale, and contaminants and can also create a roughened texture to improve coating adhesion or decorative effects. It is widely used in metal, concrete, and wood surfaces.

Abrasive media, blast methods, and equipment vary. Media include traditional silica sand (now restricted due to health concerns), garnet, aluminum oxide, steel grit or shot, glass bead, slag, and plastic media. Dry blasting uses compressed air to accelerate media; wet blasting uses water or slurry to reduce dust. Equipment includes a blast pot or pressure vessel, hoses, and a nozzle; large operations may use portable or cabinet-type systems. Surface condition, media choice, pressure, and distance determine the aggressiveness of the treatment and the final roughness.

Safety and environmental considerations are central. Silica dust exposure is a major health risk and air monitoring, ventilation, local exhaust, and personal protective equipment such as respirators, eye protection, gloves, and hearing protection are required. Containment and filtration minimize dust and media runoff; waste media must be disposed of according to regulations. Wet blasting can reduce dust and water use must be managed.

Applications and limitations: used for preparing metal coatings, removing old paint, restoring architectural stone, and texturing concrete. It can damage soft materials if misapplied and may create roughness beyond desired levels. Economic considerations include equipment cost, throughput, and cleanup of spent media and dust.