Sandpaper Grit Types

Sandpaper has been used since the 13th century, when the Chinese glued seashells and seeds to parchment. Modern sandpaper is made from organic and synthetic materials designed for specific purposes. Use the proper grit and material to ensure successful sanding results.

Definition

According to the Online Industrial Supply Corp., sandpaper grit designations refer to the number of abrasive particles that can pass through a mesh screen with specific size openings.

Materials

According to WoodZone.com, sandpapers made from aluminum oxide and garnet are used for woodworking. Silicone carbide is used for sanding metal, plastics and fiberglass. Ceramic is generally used for shaping and leveling wood.

Standards

The most commonly used standards for determining grit size include the numeric grades established by the U.S. Coated Abrasive Manufacturers Institute and the "P" grades from the Federation of European Producers of Abrasives.

Coarse Grit

Extra coarse and course grits are used for rapid removal of material. Use grits ranging from P12 to P50, or 24 to 50, for these purposes.

Medium and Fine Grits

Medium and fine grits are used to prepare bare wood for sanding, and range from P60 to P120 or 60 to 120.

Very Fine and Microgrits

Very fine grits are used for the final sanding of bare wood, and range from P150 to P220 or 150 to 220. Microgrit sandpapers are used for sanding between coats and for final sanding of finishes. Microgrits range from P240 to P2500 or 240 to 1000.

References

• Sandpaper Grit FAQs from Online Industrial Supply
• Sandpaper Information from Wood Zone

Resources

• History of Abrasives