Sandpaper Grit Guide: Which Grits Should I Use

Sandpaper grits and grades can be very confusing considering the size, coarseness, paper type, and the right tool to use with it. This guide is an easy way to get your head clear.

You’ll find a variety of sandpaper grit sizes on the market. Each of them has a particular use. This handy tool is in use for hundreds of years to give the craft a subtle finish. It is a ubiquitous tool to provide any wood project the desired finish. You can also use it for metal, or drywall related work.

Though it is called sandpaper, it isn’t made of sand. Rather, it consists of abrasives like- aluminum oxide or silicon carbide glued to cloth, paper, or sponge. It can consist of fine particles from both natural and synthetic sources. The particles, which are also known as grains or grits, are sifted and sorted by size. Then they are being bonded with paper to create an abrasive surface.

The early versions of sandpaper were made with real sand. Sand and crushed up seashells were bonded together to a parchment paper to form a crude but effective abrasive.

Modern-day sandpaper and abrasives have got precise grits. Proper sanding creates the best finishes. So, choosing the right size is very important.

Sandpaper Grit Guide

There are various types of sandpapers on the market. They’ve got different grit numbers, and every kind of grit has very different jobs than others. So, picking the right number can be difficult when you’re relatively new in this chapter. We’ve prepared some fundamental guidelines to follow while choosing the suitable sandpaper grit for your project.

Selecting the Correct Coarseness

Choosing sandpaper becomes easier due to the specific coarseness level marked on the paper. The manufacturers identify grades on the package for fast and easy pick up of the right grit. On most projects, you’ll start with coarse sandpaper and then switch to finer grits. Depending on the coarseness, sandpaper sizes are divided into different range and name as follows:

Extra Coarse Sandpaper: (24-36)

The grit size between 24 to 36 falls in this range. These are the tough stuff. You can use them for removing varnish, old paint that is very sturdy to remove, and old floors that require extra coarseness. Also, they are convenient to roughen surfaces for gluing. This range is only saved for the most challenging jobs. 

Coarse Sandpaper: (40-50)

Grit size between 40 to 50 falls in the range. This size is used for shaping wood, roughly removing previous light coats, and finishing paints.

Medium Grit: (60-100)

Ranging from 60 to 100 grit sizes, this range of sandpapers are suitable for the final rough wood shape. Except for primary sanding, this range is also used for removing marks on the material.

Fine Grit: (120-220)

It ranges from 120 to 220 grit. Mostly used for home workshops, this glass paper works for finishing touches.

Extra Fine Sandpaper: (240, 320, and 400)

Between coats of paint or varnish, you’ll need extra fine grits of 240, 320, or 400, depending on the finish you want.

Superfine Grit: (600 and above)

They are mostly suitable for polishing jobs.

Wet Dry

Another type of sandpaper you’ll come across is known as wet-dry. This type has a full grit range but is on the more delicate side. It is best for eliminating slight marks and creating a glossy finish on paint or metal.

The Difference Between Coarse and Fine Grit Sandpaper

Coarse and fine-grit sandpaper refers to the size of abrasive particles on the sandpaper. The grit size determines the roughness of the sandpaper and affects the sanding process.

Coarse grit sandpaper has larger abrasive particles and is used for heavy-duty sanding tasks, such as removing rough surfaces, rust, paint, or varnish. It’s also used for sanding down wood, metal, and plastic surfaces to prepare them for refinishing.

Fine-grit sandpaper, on the other hand, has smaller abrasive particles and is used for lighter sanding tasks, such as smoothing surfaces, removing small scratches, or preparing a surface for staining or painting. Fine-grit sandpapers are also ideal for sanding between coats of finish or for polishing.

In summary, coarse-grit sandpaper is used for aggressive sanding and removing material quickly, while fine-grit sandpaper is used for smoother sanding and preparing surfaces for finishing.

Some Facts on Sandpaper

There are two standards you may find while buying sandpaper. One is the CAMI standard; another is the FEPA standard. Now, what’s the difference between them?

The main difference is the location they are being produced. CAMI is USA based, where FEPA is European. CAMI is the Coated Abrasive Manufacturers Institute in the United States. On behalf of them, The Carborundum Company, Washington produces the supply. It determines a gradation scale measured in microns.

On the other hand, sandpaper grit sized by the Federation of European Producers of Abrasives or FEPA is manufactured by  Staatliche Material Strafanstalt, Darmstadt, Germany, for European grade of Coated abrasives. They indicate the grit size with the letter “P,” like-  P-180 or P-220.

Though they are not identical, you can get something similar to the CAMI number by choosing the closest FEPA grit.

Why and When Do You Use Sandpaper?

A range of grit sizes is available for different uses. You can use sandpaper for the following projects:

Smoothing Surface:

In painting and wood finishing work, you’ll sand the surface with a fine-grit to make it smoother.

Removing Stains:

For sander to remove old paint or a layer of material from wood, you’ll need a coarser grit of sandpaper.

Roughening Surface:

As preparation for gluing, you’ll make the surface rough with comparatively coarse sandpaper.

What Is Sandpaper Grit? What Does the Number on It Say?

The sandpaper grit indicates the coarseness of sandpaper. It’s the size of abrasive material on paper. For example- 40-grit sandpaper is more coarse than 60-grit. Again, 180-grit is less subtle than 220-grit. So, the higher the grit number, the finer the abrasive.

Divisions

Sandpaper is mainly divisible into two main subdivisions- macro and micro.

Macro Grit

Macro grits are used mainly for roughly shaping the wood. These grits range from medium to coarse sections. They range from the very low to mid grit in number. 

Micro Grit

Micro grits are used for polishing jobs. They have a more refined tone. These sandpapers have a higher grit number, but they’re least coarse. It’s a class of finer abrasives. 

Sandpaper Using Tips and Precautions

*Power sander works faster and produces more dust than other handheld tools. Use a dust collecting tool, or better use a shop vacuum connecting with the power tool. Vacuum or wipe off the dust between the grits.

*Wear a respirator or breathing protector, fog-proof goggles to protect yourself from dust and splinters. You may also need hearing protection and gloves, depending on the tool you use.

*Don’t start the project right away. Instead, practice on some scrap wood first.

*Use the grit that’s right for the task. And move on to the finer ones on the go.

*When you’re power-sanding, don’t pressurize on the surface. Otherwise, you’ll end up getting deep marks that are hard to remove and are hardly visible until you stain the wood.

*Also, don’t rush while power-sanding. It’ll give the project a poor finish.

Conclusion

Among the various grades and grits, pick wisely the right number. I hope this article helped you get your questions cleared about sandpaper grits.

Also, don’t forget to take safety precautions before you start working. Now head to the hardware store to match your needs and start your project right off.

Relevant Resources:

• Details Overview  Drywall Sanders
• Sanders for Refinishing Furniture Guide
• Best Random Orbital Sanders for Woodworking