How Is Sandpaper Made? What Makes Abrasive Paper So Effective

Sandpaper is one of the most straightforward cutting tools in a workshop. So what—is sandpaper really a tool? Yes, it is. Of course, woodworkers rarely consider it a hand tool. However, sandpaper is made from abrasive or sharply pointed minerals glued onto a paper backing to cut away or smooth rough edges. Although the name would suggest that this abrasive material is made from gluing sand onto paper, these two products are not used in its production. So! How Is Sandpaper Made

Anyone working with wood knows the value of using sandpaper. From rubbing away old materials from stock to sanding between coats of finish, sandpaper is the most versatile tool you could imagine. 

Interestingly, the basic science behind sandpaper hasn’t changed in hundreds of years. However, using the latest technological advances, sandpaper production is now a highly specialized process. 

This article explores the “nitty-gritty” of sandpaper. You will learn about the history of sandpaper and why it is one of the most useful tools in a workshop. Additionally, you will also learn how to make sandpaper. 

What Is Sandpaper Made Of?

Sandpaper is a coated abrasive material containing a range of materials, including grains of aluminum oxide, silicon carbide, ceramic alumina, or garnet. These abrasive minerals are applied to a pliable synthetic material. Typically, a resin or epoxy secures the abrasive grains to the backing. The thickness of this determines the sandpaper’s flexibility and rigidness.

The trick with making sandpaper effective is the proper application of the abrasive minerals. To sand wood, metal, glass, or other materials, the sandpaper coating must be uniform and perfectly level. 

So, how is sandpaper made? First, the adhesive epoxy or resin is applied to a continuous roll of backing material. This is fed under a roller that sits over a bed of abrasive minerals. A static charge causes the grit to jump up, and the dancing particles stick to the backing material. 

The result is a sharp-edged “paper,” and its grit determines how abrasive the sandpaper is. Low grit sandpaper refers to a coarser grade, whereas a higher grit means a finer, less abrasive finish. 

Who Invented Sandpaper?

Sandpaper is an essential tool for many different types of projects, from woodworking to metalworking. Centuries ago, the Egyptians used sandstone as an abrasive material to help build intricate artifacts. However, the invention of applying abrasive grains to a flexible material probably has its origins in ancient China. 

Thirteenth-Century China and the Invention of Sandpaper

The origins of sandpaper, similar to what we use in the workshop, are traced back to China in the thirteenth century. According to reports by the American Chemical Society, the ancient Chinese used an “amalgam of crushed seashells bonded to parchment paper.”

They used crushed seashells, sand, or seeds and then bound them to parchment with natural gums. This primitive form of sandpaper was used for various purposes, such as smoothing wood and metal surfaces, polishing stone and ceramic objects, and even sharpening knives.

This technique eventually spread throughout Europe and became known as “sandpaper” due to its similarity to the texture of sand. Today, sandpaper is widely used in many industries, including automotive repair and woodworking.

3M “Invented” Modern Sandpaper

According to the Smithsonian Institute, the Minnesota Mining and Manufacturing Company (now called 3M) started using mined minerals applied to a paper backing. However, it was in 1921 when 3M patented the first “Wetordry” waterproof sandpaper. This was a water-resistant abrasive material that would reduce dust in woodworking and the automotive industry. 

Does Sandpaper Have Sand in It?

Despite its name, sandpaper no longer contains sand or glass. Rather than using relatively non-abrasive sand, modern sandpaper uses abrasive materials like aluminum oxide, silicon carbide, diamond, or garnet. These minerals give sandpaper a specific abrasiveness, from coarse grits to finger grits, depending on the type of finish you are looking for.  

What Materials Do You Need to Make Sandpaper?

The production of sandpaper uses a range of materials—natural and synthetic. Interestingly, woodworkers rarely think they work with a range of precious gems in their workshop. Still, nothing could be further from the truth. In reality, some materials used to make sandpaper are derived from gemstones like diamonds, sapphires, and zirconia. 

Some of the natural minerals commonly used in making sandpaper. 

Aluminum Oxide

Aluminum oxide is a brown-colored mineral that is highly abrasive and commonly used in sandpaper for woodworking. The tough, abrasive mineral can easily remove rust, paint, and other debris from wood and metal surfaces. Aluminum oxide is a component in sapphires and rubies. 

Aluminum oxide is extremely durable and resistant to wear, making it an excellent choice for industrial applications. Its hardness makes it difficult to break down or damage, which means it can be reused multiple times without losing its effectiveness. Additionally, aluminum oxide does not contain hazardous materials or chemicals, making it safe for many industries. Finally, its versatility makes it a great choice for commercial and residential projects.

Alumina Zirconia

Alumina zirconia—also known as ceramic—is a rough, durable mineral commonly found in sandpaper. It is usually blended with other abrasive materials due to its higher expense. However, the coarser grit of zirc or zirconium makes it ideal for sandpaper, sanding discs, and abrasive belts for metal and glass. 

Silicon Carbide

Silicon carbide is a mineral that is commonly used in sandpaper. It is known for its ability to sand both wet and dry surfaces. This makes it ideal for many applications, such as smoothing out wood or metal surfaces. However, silicon carbide is brittle, and the sandpaper tends to wear out more quickly than other types of sandpaper. 

Garnet

Garnet is a popular abrasive mineral used in producing sandpaper. This type of tan-colored mineral is designed to produce quality, smooth finishes and is excellent for all-purpose sanding. However, it is commonly used as a finishing sandpaper for furniture projects.

Emery

Called emery paper, this abrasive material is made from aluminum oxide, iron, and silicon oxides. This type of abrasive paper has fine grit and is typically used to finish or polish metal objects. It can also be used wet or dry or have oil as a lubricant.

Diamond

Sandpapers containing diamond grains are typically used for sanding high-grade ceramics. Sandpapers with diamond grit are flexible and ideal for working on glaze, glass, stone, and tile. It is also highly durable and doesn’t wear down as fast as other sandpapers. However, its use in woodworking is limited. 

What is Sandpaper Backing Made From?

Sandpaper backing is made from paper, cloth, polyester, mesh, foam, or other woven fabrics. The most common types of sandpaper for woodworking are made from grades of reinforced paper. These are usually the cheapest and suitable for light to medium sanding. 

Traditional sandpaper with paper backing is graded from A to G, with A being the lightest and most flexible. Because this type of sandpaper is the more affordable, it is usually the most popular. However, it is prone to tearing under heavy or continuous use.

Cloth-backed abrasives made from woven material are more durable and expensive. These “sandpapers” could be made from natural or synthetic materials—cotton, nylon, and polyester. In addition to being longer-lasting, cloth abrasives are better for wet and dry applications. They are also a popular choice for sanding discs or belts. 

How is Sandpaper Made

Making sandpaper is generally straightforward, regardless of the process used. It involves gluing abrasive grains or powder to a paper, cloth, or mesh backing. But do you want to learn how to make your own sandpaper at home? If so, here are the instructions:

·        Choose a thick type of paper and lay it flat on a board.

·        Apply glue or another adhesive to the surface, spreading it evenly with a putty knife. 

·        Next, take coarse sand and spread it over the paper’s surface while the glue is still wet. Try to fill the paper with as must abrasive material as possible.

·        Then, allow the glue to dry.

·        To ensure the abrasive is firm on the paper, place a board on top of the homemade sandpaper and clamp the two boards together. Wait for a day.

·        The last step involves removing the clamps, separating the boards, and carefully removing the sandpaper. 

Although it is possible to make sandpaper at home, the question is—should you? Typically, homemade sandpaper is inferior to the kind you can buy at the hardware store. Also, it is difficult to get an even surface, and gaps in grit coverage are common. The result? You could end up damaging work-pieces by scratching them. In the end, sandpaper is one of the cheapest finishing tools you can buy in a workshop. 

How to Choose the Right Grit Sandpaper

Choosing the right sandpaper for a project is essential for achieving the desired results. Sandpaper comes in a range of grit sizes, and the sandpaper’s grit size determines its abrasiveness. Higher numbers indicate finer grits, but it’s important to understand which abrasive you are using to ensure you don’t cause any damage.

Short guide to choosing the right sandpaper:

·        Coarse grit (24 – 60): For removing material from wood quickly.

·        Medium grit (80): To sand bare wood to prepare it for finishing. 

·        Fine grit (100 – 220): To gently remove the top layer of finish or sand bare wood.

·        Very fine to ultra-fine grit (240 – 1000): For sanding between finishes, final wood finishing, and polishing thick finishes.

Is Sandpaper a Raw Material?

Sandpaper is traditionally made from raw materials that include paper and cloth as backing and abrasive minerals to cut away at wood, metal, ceramics, and glass surfaces. Abrasives are typically mined minerals that have abrasive qualities. Or they can be synthetic materials for specialized use. Although it is made from raw materials, sandpaper itself is not classed as a raw material.

How is Sandpaper Made— In Conclusion

In conclusion, sandpaper is a versatile tool that can be used for a variety of applications. It is made from abrasive grains or powder glued to a paper, cloth, or mesh backing. Sandpaper comes in different grit sizes and can be used to sand wood, metal, plastic, and other materials. It is important to choose the right grit size for the job to avoid damaging work-pieces.