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What sandpaper grit sizes are available?

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The size of the particles on a piece of sandpaper A sandpaper’s grit size means the size of the particles that are embedded in the sandpaper. The particles are measured in micrometers. A micrometer, also known as micron, is one millionth of a metre, or one thousandth of a millimetre.
Measuring grit sizes Grit size can be measured in terms of two standards, which are the Coated Abrasive Manufacturers Institute (CAMI) and the Federation of European Producers of Abrasives (FEPA). Both standards separate grit sizes into two categories: macro grits and micro grits.
 Donkee says 'Sanding with the wrong sandpaper can damage your workpiece'

Macro grits

Macro grit sandpaper Macro grit sizes of sandpaper can be categorised into the following sub-types.
Extra coarse sandpaper can be used to sand hardwood floors

Extra coarse

Extra coarse grits are larger in size and are used for the fast removal of all kinds of materials, especially the initial sanding of an object, such as a hardwood floor. The average diameter of an extra coarse grit would be between 530 and 1815 micrometers.

Coarse sandpaper can be used to remove unwanted materials

Coarse

Coarse grits are designed for the rapid removal of unwanted material. The average diameter of a coarse grit is between 336 and 425 micrometers.

Medium sandpaper can be used to remove varnish from wood

Medium

Medium grits are designed for the gentle removal of varnish or sanding bare wood in preparation for a finish. The average diameter of a medium grit is between 190 and 265 micrometers.

Fine grit sandpaper used from removing water stains

Fine

Fine grits are not suitable for removing varnish or paint from wood. They are often used for sanding bare wood in preparation for a finish. They are also used to remove water stains from wood. The average diameter of a fine grit is between 115 and 162 micrometers.

Very fine macro grits sandpaper used for sanding bare wood

Very fine

Very fine macro grits are only used for the sanding of bare woods. The average diameter of a very fine macro grit would be between 66 and 100 micrometers.

Macro grit sizes classified by CAMI and FEPA There are various levels of grit available within the sub-types of macro grit, and these are classified differently by the CAMI and FEPA standards. Below is a table demonstrating how each standard classifies the sizes.
CAMI  FEPA
 Extra coarse  24, 30, 36  P12, P16, P20, P24, P30, P36
 Coarse  40, 50, 60  P40, P50
 Medium  80  P60, P80
 Fine  100, 120  P100, P120
 Very fine  150, 190, 220  P150, P180, P220

Micro grits

Micro grit sandpaper Micro grit sizes of sandpaper can be categorised into the following sub-types.
Use a very fine micro grit sandpaper to sand in between coats

Very fine

Very fine micro grit sandpapers are used for a sanding finish between consecutive coats, for example between a coat of paint and a varnish. The average diameter of a very fine micro grit is between 40.5 and 58.5 micrometers.

Extra fine sandpaper used for initial polishing

Extra fine

Extra fine grits are designed for the initial polishing of wood. The average diameter of an extra fine grit is between 25.8 and 36 micrometers.

Super fine sandpaper is ideal for the final sanding finish

Super fine

Super fine grits are ideal to be used for the final sanding finish on a workpiece. Their average diameter is between 15.3 and 23 micrometers.

Ultra-fine sandpaper used for final sanding of thick finishes

Ultra-fine

Ultra-fine grits can be used for the final sanding and polishing of thick layers of varnish and paint, in order to give a workpiece that finishing touch. Their average diameter is as small as 8.4 and 12.6 micrometers.

Micro grit sizes classified by CAMI and FEPA There are also various levels of grit available within the sub-types or micro grit, and these are classified differently by the CAMI and FEPA standards. Below is a table demonstrating how each standard classifies the sizes.
CAMI  FEPA
Very fine  240  P240, P280, P320, P360
 Extra fine  320, 360  P400, P500, P600
 Super fine  400, 500, 600  P800, P1000, P1200
 Ultra-fine  800, 1000  P1500, P2000, P2500, P3000, P6000

What grit size should you choose?

Which grit size should you choose? When using sandpaper, it is best to start with a coarse to medium size grit if you need to remove any unwanted coatings such as varnish or paint. Macro grits are also used to even out a rough surface.
Different sandpaper grit sizes are available For final sanding, you should move on to a finer grit size to give your workpiece a smoother finish. Don’t be tempted to skip straight from a coarse grit to a fine one during sanding, as this could actually cost you time rather than saving it.