This is a natural abrasive that is mostly used in woodworking as a final sanding paper. Garnet is not friable like aluminum oxide and wears out faster, though; it produces a smoother surface than aluminum oxide. It has the tendency to seal off a wood's grain or burnish which allows the pigmented stains to penetrate woods, such as lauan, pine and birch more evenly.
This type of sandpaper exhibits a high degree of friability and is commonly used in woodworking to create new, sharp edges. Aluminum oxide has a self-renewing property that makes it to last longer than other types of sandpapers.
Ceramics may be the hardest of all of the abrasives commonly available and it is not friable like garnet and aluminum oxide. In woodworking, it is available in the roughest grades for quick wood removal, leveling and shaping and is available for use on belt sanders.
This type of sandpaper is harder than garnet and aluminum and therefore it is suitable for cutting harder materials, such as fiberglass, paint, plastic and metal. Silicon carbide is a friable abrasive that tend to wear out faster than aluminum oxide.
The backer is printed on the back of the paper. The grits are poured from the bags into a hopper after resin has been applied on the paper. It is then fed through a vat containing the selected resin. The grit is sprinkled onto a conveyor belt that is electronically charged. As the conveyor moves along, the paper is brought down across a roller approximately 2 inches above the conveyor. The resin coated paper is allowed to dry, then a second coat of resin is added to it to give it a longer life in use. It is left to dry, then run through a flexer. The backer is applied just before cutting and packaging.