What Is Sandpaper Made Of?

Sandpaper has been used for centuries. Suitable for a myriad of applications, from smoothing a wooden surface to removing paint from a car, sandpaper is truly a utilitarian tool. But while we all use it, how many of us actually know what sandpaper is made of? Is it really made from sand and paper, or is there a more complicated story behind this inexpensive abrasive?

Definition

Sandpaper is composed of three layers: a paper, or fabric base, an adhesive, and an abrasive top layer composed of a variety of substances.

Originally

Originally, sandpaper was made from paper with a variety of crushed natural substances applied on top with glue. Glass, shells and even shark skin were some of the earliest abrasives used to make sandpaper.

Backing

Today, sandpaper is either made of varying grades of paper for backing, which are rated according to thickness, or from fabrics, such as cotton, polyester or stronger Mylar.

Adhesives

For sandpaper not used in machine sanding, glue is still used as the adhesive between the backing and abrasive layer, but for sandpapers that have to withstand high heat levels; resin is used as the adhesive.

Abrasives

A variety of different abrasives are used in modern sandpapers in their ground form, and sandpaper is graded according to its abrasive quality, from rough to smooth. Silicon carbide, garnets, emery and the most common, aluminum oxide, are all used today in a ground or crushed layer to make the abrasive side of sandpaper.