Complete Guide to Sandpaper Grit Classification

Sandpaper Grit Classification

In the world of woodworking, sandpaper can be your best friend – if you have the right grit. Start sanding with the wrong grit and sandpaper can also be your worst enemy. With proper sanding, you can create a fantastic finish for any wood project, but you’ve got to know how to choose the right sandpaper for your work.

The Basics of Sandpaper

You have two basic options available to you when you need sandpaper: sanding by hand or sanding with a power tool.

A power-sanding product, such as one of the best random orbital sanders, can help you to remove materials quickly for your woodworking project. If you have a blemish in your project or you need to level or shape your wood, this is going to be your best option. Power-sanding products tend to come in either discs, belts, or sheets. You’ll also find them available in specific shapes for specific tools.

Hand-sanding products allow you to put a finishing touch on your woodworking projects. Hand-sanding doesn’t create the same levels of movement or pressure across the wood, which means you have more overall control over the final product. Sanding by hand also allows you to reach areas that power-sanding products are unable to reach.

What Are the Different Types of Sandpaper?

Sandpapers will usually feature either a natural abrasive or a man-made abrasive. Each option has certain advantages that come with it. By choosing the correct type of sandpaper abrasive for your woodworking project, it will be much easier to achieve the results that you want to achieve.

Here are the top options that are available right now.

  • Aluminum Oxide. This is a common multi-purpose sandpaper that you’ll find at most stores. It works well because the abrasive particles continue to break during the sanding process, allowing you to have consistently sharp edges to use as you are sanding.
  • This type of abrasive works well for raw wood products when you need to do finishing work. It effectively removes light scratches. The particles wear out quickly, so it works best for light sanding needs only.
  • Silicon Carbide. This abrasive works best when you have a heavy sanding need for your woodworking project. As a sandpaper it doesn’t last very long, but it also handles tough jobs quickly. You can smooth joints, remove paint, and even use it for wet sanding if necessary.
  • Ceramic Alumina. This sandpaper abrasive is usually only available for discs or belt sanders. It’s highly aggressive, so should only be used on wood for large, difficult repair needs.
  • This natural material creates a unique abrasive that is coarse, but still somewhat gentle compared to your other sandpaper options. This sandpaper also tends to come with a cloth back, making it less abrasive on your hands for hand-sanding needs. It’s fine enough to give you a polish, but strong enough to remove paint.

If you’re looking for a good multipurpose sandpaper for your woodworking projects, we highly recommend using an Emery paper. Often referred to as an Emery cloth, this option from 3M offers you assorted grit sizes so that you can meet a variety of small project needs with a single purchase.

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The Differences Between Open-Coat and Closed-Coat Sandpapers

Sometimes you may see sandpaper referred to as being “open-coat” or “closed-coat” in its description. This refers to what the backing of the sandpaper happens to be. Paper is the traditional backing for this product, hence the name “sandpaper,” but film backing is also an option.

If the sandpaper is an open-coat product, then it has empty space on the backing. This allows for materials to accumulate without reducing the performance of the sandpaper. Closed-coat sandpapers have abrasives that cover the entire backing, allowing you to remove more materials.

Cloth and film backing, either open or closed, open up the option for wet sanding.

Most hand-sanding papers are going to be closed-coat, while most power sanding options are going to be open-coat.

What Do the Grit Numbers Mean on Sandpaper Products?

Have you ever noticed that all sandpaper products come with a number assigned to them? This number is called the “Grit Number.” It is an indication of what the particle size happens to be on that product. Grit numbers on sandpaper work from highest to lowest, so a lower number indicates a larger abrasive particle.

There are numerous grit number options that are available today. At most retail outlets, you’ll find the range is typically between 24-2,000. If you shop online, you can find grit numbers that go well above 2,000 as well.

3M even makes a 5,000 grit performance sandpaper: Click here to look at prices on Amazon and get a great deal.

For the average woodworking project, you’ll want to look at grit numbers that are between 60-320. The specific grit number you need will depend on what task you must complete. Here is a short guide as to what to expect from certain grit numbers.

  • 36-100. These grit numbers are excellent for material removal. You can strip away a finish, remove rust or flaws from wood, and shape your wood effectively. Power sanders tend to use these grit numbers the most effectively.
  • 100-180. These grit numbers are your most versatile options. You can prepare a bare surface for a finish, smooth out a work piece, or remove scratches pretty effectively. Hand-sanding or power sanding are both possible with these grit numbers.
  • 180-320. These are your grit numbers for finishing work. A higher number in this category will create a finer finish. You can remove raised fibers or create scuffing between coats to finalize a smooth finish.

Which Sandpaper Option is Right for You?

Modern sandpaper may come via a sanding sponge, a power-sanding disc, on a stripping pad, or on some other hybrid product. The end result, however, will always be the same. When you know what type of abrasive you need and what size it should be, your woodworking project has the best possible chance to meet your expectations.

Whenever you start sanding, making sure that you wear appropriate personal protective equipment. This includes breathing and eye protection, even if you are hand-sanding. Dust and abrasive particles can cause more damage than you might realize.

So select the right sandpaper from this guide and get started. You’ll find that sandpaper really is your best friend in the field of woodworking.