Previously, in a series of articles, we discussed the topic of surface preparation, methods, and the importance of this issue in the painting process.

But given that sanders are simple, inexpensive, and very widely used tools among all preparation methods, we will focus on them specifically in this article.

The simplest and most common tool for removing debris and preparing a surface is sandpaper.[1] This tool consists of a special paper sheet with coarse abrasive particles attached to it. The coarser the particles, the more abrasive the sandpaper will be. Some sandpapers are used for dry sanding, while others are used for wet sanding.

Common materials used for abrasive fibers are mostly paper, cloth, vulcanized fibers, and plastic films, and a variety of abrasives are used on it in sizes ranging from very coarse (~2 mm) to very fine (sub-micrometer). Common abrasives in the production of abrasives are usually made of these materials:

Glass: which is not used much today.

Flint: Not widely used today.

Garnet: Commonly used in wood sandpaper used in carpentry.

Sandstone (a mixture of corundum and magnetite): Usually used for grinding or polishing metals

Aluminum Oxide: The most common abrasive in modern use, with the widest variety of particle sizes and lowest unit cost, it can be used for finishing metal or wood surfaces.

Silicon Carbide: This abrasive is available in very coarse to fine grits and is common for use in wet applications.

Alumina-zirconia: (an aluminum oxide-zirconium oxide alloy) used for machining applications

Chromium oxide: Used in very fine micron sandpaper (micrometer level).

Diamond: Used for finishing and polishing hard metals, ceramics, and glass.

Some sandpapers made from water-resistant fibers can be used in wet conditions. These sandpapers are known as wet sandpapers or waterproof sandpapers in the market.

The international standard for grading abrasives used in sandpaper is ISO 6344. The table below lists the standard for sandpaper and its abrasives.