Sandpaper Composition

Sandpaper consists of three parts: a substrate, abrasive particles, and a binder. The substrate is typically paper, cloth, or polyester film. Polyester film substrates (such as felt-backed polyester film sandpaper) are water-resistant, oil-resistant, and tear-resistant, making them suitable for wet or high-intensity sanding scenarios. Paper substrates are low-cost but less durable. Cloth substrates are flexible and suitable for sanding curved surfaces. The abrasive particles are the core of sandpaper, and common materials include alumina, silicon carbide, and garnet. Alumina abrasives have high hardness and long lifespan, making them suitable for sanding metals and wood. Silicon carbide abrasives are sharper and often used for hard materials such as glass and ceramics. Garnet abrasives are mostly used for coarse sanding of wood.