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Sandpaper Guide: Grit & Grade

Sandpaper Guide: Grit & Grade

Sanding is not only useful but can make all the difference in a woodworking, metal or drywall project. Sanding can be done by hand as well as in tandem with power tools such as electric sanders to create the best finishes on these materials. Sanding by hand works well for woodworking and finishing, especially for giving surfaces a lighter touch. Sanding with power tools helps scrape off material quicker, with the added potency of shaping and leveling wood. It’s also used to prepare metals for a paint job.

 

Sandpaper for power sanding is sold in sheets, belts and discs. Regardless of which route your application requires you to take—hand-sanding or power-sanding—knowing the differences between the types of sandpaper is key to completing a sanding application. Choose accordingly with our sandpaper grit chart and by following the nuances in grades and material.

What is Grit?

The grit of sandpapers is a rating of the size of abrasive materials on the sandpaper. The higher the grit number is equivalent to a finer abrasive, which creates smoother surface finishes. Lower grit numbers represent coarser abrasives that scrape off materials much quicker. In the chart below, the grit size is measured via both the CAMI (Coated Abrasives Manufacturing Institute) and FEPA (Federation of European Producers of Abrasives) standards, the latter of which is preceded by a “P.” There are two main subdivisions, micro and macro, with many more gradations included.

Micro Grits

Micro grits are a class of finer abrasives. They include higher grit numbers. Micro grit-sized sandpapers are commonly used on wood and some on drywall.

Type Description CAMI FEPA Diameter Used for
Ultra Fine Most delicate abrasives 800-1,000 P1,500,
P2,000,
P2,500
8.4-12.6 micrometers Final sanding and polishing thick finishes
Super Fine Slightly wipes away patches/small inconsistencies but not strong enough for removal 400-600 P800, P1000, or P1200 15.3 to 23.0 micrometers Final wood finishing
Extra Fine Slightly less fine and more abrasive than Super Fine 360 or 320 P400, P500, or P600 25.8 to 36.0 micrometers Initiative methods for wood polishing
Very Fine The least fine of the micro abrasives 240 P240, P280 or P320 40.5 to 58.5 micrometers Sanding finishes between consecutive coats and drywall and wood

Macro Grits

Macro grits are a class of abrasives that range from medium to coarse sandpaper calibers. They feature mid to low grit numbers. Macro grit-sized sandpapers are commonly used on tougher wood and metals and have a stronger clearance.

Type Description CAMI FEPA Diameter Used for
Very Fine A coarser material than Very Fine under the micro abrasives 80 P60 or P80 190 to 265 micrometers Sanding on bare wood
Fine Cannot remove varnish or paint on wood 100 or 120 P100, P120 115 to 162 micrometers Preparing wood for finishing, cleaning plaster and removing water stains on wood
Medium Medium to coarse surface texture after sanding 80 P60, or P80 190 to 265 micrometers Sanding bare wood to prepare it for removing varnish and final finishing
Coarse Has the ability to remove material rapidly 40, 50 or 60 P40 or P50 336 to 425 micrometers Wiping away a layer of debris or finish with minimal effort
Extra Coarse Quickens the removal of most materials rapidly 24, 30 or 36 P30, P36, P16 or P12 530 to 1,815 micrometers Initial efforts in hardwood floor sanding

More Facts on Sandpaper Types

Besides the grits and grades, sandpaper is made out of materials that vary chemically. It can be made from the grains of a natural mineral called garnet, or from synthetic ones like aluminum oxide, alumina-zirconia or silicone carbide. Irrespective of the sandpaper you work with, it must have a strong bond between the sandpaper grit and its backing material. If it doesn’t, the grit and backing material may become separated during use, ruining your application. Backing for sandpaper includes paper, cotton, polyester, rayon, PET film and rubber. Mylar is used as backing for extremely fine grits.

Pub. 01/2017

The product statements contained herein are intended for informational purposes only. Such product statements do not constitute a product recommendation or representation as to the appropriateness for a specific application or use. W. W. Grainger, Inc. does not guarantee the result of product operation or assume any liability for personal injury or property damage resulting from the use of such products.