Flap Discs for Angle Grinder. Flapper disk grinder

How to Select the Right Flap Disc for Your Project

Are you exploring flap discs to use for your next project? Maybe you’ve been using grinding wheels all this time and have overlooked the benefits of a flap disc. Flap discs are highly versatile tools and can meet your needs in a variety of applications — from stock removal to grinding and finishing. Many operators actually prefer flap discs over grinding wheels during operation, and when it comes to your next project, flap discs may be just the solution you need.

Keep reading our flap disc buying guide to learn more about these tools and how to select the right flap disc for your project.

What Are Flap Discs?

Flap discs are made from multiple overlapping pieces of abrasives or ‘flaps,’ which is how they got their name. Flap discs are designed for right angle grinder applications ranging from heavy stock removal to surface blending and smooth finishing.

While the first abrasive flap discs for high-speed angle grinders were developed towards the end of the 1970s and were somewhat basic, today’s versions offer an array of diversity. You should strongly consider a flap disc over a grinding wheel if you need a superior finish and greater ease of use during operation.

Advantages of Flap Discs

Flap discs are versatile: they can grind, blend and finish. They are also lightweight, easy to maneuver, and require less change over time. When performing a job, many operators prefer flap discs over grinding wheels due to lower vibration and noise levels. Plus, they offer cooler cutting with minimal scratching.

For instance, grinding wheels have to be discarded even after a small area of abrasive is worn out. Comparatively, flap discs remain useful even after the flaps erode, which results in a longer operating life. Compared to a flap disc, grinding wheels are cheaper on a unit cost basis. However, if you consider the versatility, durability and ease of use provided by flap discs, they are more cost-effective in the long run. Because of these advantages, the popularity of flap discs has soared in the last several years.

How to Select the Right Flap Disc

When it comes to flap discs, there’s a variety of discs available in today’s marketplace. Let’s start by understanding the various components of a flap disc, so you know how to select the right disc for the right task:

Flap Disc Shape

Is stock removal your primary objective, or do you want a smooth finish? Choosing the right disc shape is the single-most important variable, and the shape will help you effectively achieve your results. Flap discs are almost always used on right angle grinders, and they are applied to your work at an angle or parallel to it. Flap discs are available in two shapes: conical or flat-shape.

  • Conical flap disc: Conical flap discs are your best friends when you need to remove a lot of material in a small amount of time. They can be used for edge-working as well as on contoured applications. The flaps in a conical flap disc are angled. As a result, these discs offer a greater surface area for stock removal on horizontal surfaces.
  • Flat flap disc: While conical discs are great for Rapid stock removal, flat flap discs are best for blending and superior finishing. They are mostly used on flat surfaces. The flaps of a flap disc are adhered to a backing plate which provides stability during operation.

Flap Disc Material

The backing plate material is also an important variable to consider when choosing flap discs for your application. Fiberglass, plastic and metal are the most popular backing plate materials:

  • Fiberglass: Being strong, durable, lightweight and safe, fiberglass is the most popular material choice. Fiberglass creates a strong bond with adhesives and does not contaminate the working surface. This type of plate also gets consumed during use, and it absorbs vibration very well. Remember, fiberglass backing is made out of layers of fiberglass that are mesh-bonded and pressed together. With more layers and a higher mesh density, the backing will be stronger and more durable — this is an important consideration when you’re examining the detailed specs of a flap disc.
  • Plastic: Another popular backing material is plastic, and nylon is the most commonly used plastic. These backings can be trimmed which allow longer usage of flaps, specifically during blending and finishing. These days, plastic is becoming an increasingly attractive choice due to its conformability and costs.
  • Metal: Metal backing plates are the safest choice, and they’re great when you need extra strength and firm support. Aluminum is a commonly used metal. Since metal plates are expensive, they should also be used where they make the most sense. For example, when working with flap discs on concrete or stone applications, use flap discs with metals for strong support and better performance. Metals don’t get consumed during use, but metal plates can be easily recycled when a flap disc is past its useful life.

Abrasive Flap Densities

What does abrasive flap density mean? Think of the density as the total amount of abrasive area provided by the flaps on a flap disc. This area depends on the quantity of flaps on a disc, their angle relative to the center of the disc and how far they are spaced. Remember, each variable can impact the amount of disc area available to work on your job.

  • Standard density: Standard density flaps are optimal for fast stock removal and heavy-duty applications.
  • High density: High-density flaps are best-suited when working on curved or uneven jobs, as well as during finishing. Don’t take the description of flap disc density at face value. Consider the number of flaps, angle and spacing to differentiate between two discs, both of which may specify “standard density flaps” or “high-density flaps.”

Abrasive Grit Material

Flap discs can be used for a variety of applications, whether it’s metal or woodworking, concrete grinding or finishing, stone smoothing or finishing, paint or rust removal, and more. In order to get the maximum benefits out of flap discs, it’s important to choose the right abrasive grit material for your specific job needs. Let’s look at the most commonly used abrasive grit types:

  • Ceramic Alumina: This material is great for stainless steel or alloy metals application. With Ceramic Alumina, the grit material ruptures at a micro level during operation. This produces a constant supply of sharp cutting surfaces. As a result, it enables faster cutting while allowing the entire grain to be used. As the entire grain is getting used up in the cutting process, these discs offer higher durability.
  • Zirconia Alumina: This is a blend of Zirconia and Aluminum Oxide grain, and it’s great for carbon and mild steel application. Zirconia Alumina costs less than Ceramic Alumina, and it provides a great cut rate for the cost.
  • Aluminum Oxide: This is the original grit material used in the 1970s when flap discs were first introduced. It’s also the lowest-cost option. Today, it is recommended for smaller jobs where the product being produced is low-value.

Grit Size

You’re probably familiar with grit size if you’ve been using grinding wheels. Grit size is the final variable you have to choose based on your ultimate goal and what you’re trying to achieve. For stock removal or common grinding, use abrasives with lower grit numbers. On the other end of the spectrum, use higher grit sizes if you’re trying to achieve smooth finishing.

Flap Disc Uses

Flap discs initially became popular for use on metals, especially in welding applications. Today, various flap discs are available to use for different surfaces:

  • Flap discs for aluminum: Compared to other metals, aluminum has a lower melting temperature and melts easily. This causes the aluminum material to coat the flap disc during grinding, covering the grit and exposing only bits of aluminum. For stock removal, use a T29 conical disc at a 15-degree angle to provide maximum surface contact. If you need to surface-clean or provide a smooth finish, use a T27 flat disc that’s parallel to your work area. For best results, use light and even pressure to optimize the grinding process and reduce loading.
  • Flap discs for wood: Flap discs are great tools for working on wood. The flap discs designed for use on wood are similar in nature to the ones designed for use on metal. You can use aluminum oxide grits for wood applications. For wood, you should also use the flap discs on your angle grinder just like you would use a grinding wheel. In order to avoid deep scratches, start with a heavy grit and work your way up to the lighter grits (100) for a final finish. For wood sanding, work your way through 120, 150, 180 and 220-grit sizes to achieve a furniture-grade surface.
  • Flap discs for paint removal: Do you have a metal object that’s rusted but you know you can still extend its life? Do you have old, chipping paint on your car that you need to remove to give it a like-new appearance? Flap discs, especially non-woven discs, are ideal tools for removing paint and rust. Non-woven flap discs, or the ones with aluminum oxide, can be used for paint or rust removal applications. As with flap discs in general, these discs can grind and finish in a single operation while offering a smooth and controlled grind.
flap, discs, angle, grinder
  • Flap discs for concrete: You’ll need silicon carbide or diamond flap discs for aggressive stock removal on concrete. Silicon carbide and diamond are some of the hardest materials in the world. Using these discs will allow you to work on concrete surfaces without the need for high pressure. These flap discs have rigid backings, and they can also be used on other surfaces such as engineered stone, granite, marble and ceramics.

Getting Started With Your Flap Discs

Before you start using any shop tool, you should always make sure you:

  • Understand your tool
  • Read the user’s manual
  • Wear the proper safety equipment
  • Ensure a safe working area
  • Know what you’re using your tool for

With flap discs, you need to consider the size and scope of your project. Do you have to remove stock aggressively, or is smooth finishing your goal? Or do you want a grind that’s somewhere in between? Whatever your answer, there’s a flap disc that’s right for your situation.

Don’t limit flap disc to the common metals. Flap discs can also be used across various surfaces, including aluminum, wood, concrete, engineered stone, granite and more. For each of these applications, whether you’re grinding or finishing, make sure you choose the right flap disc. Remember, conical shaped flap discs are great for stock removal and flat flap discs are best for finishing.

Flap disc backing material is important as it provides support during operation. Use metal backings for concrete or engineered stones, and use fiberglass or plastic backings for most metal or wood jobs. Also consider your abrasive grit material, and choose your grit size to achieve the desired results. For common grinding, use abrasives with lower grit numbers. For smooth finishing, use higher grit sizes.

flap, discs, angle, grinder

Using a flap disc instead of a traditional tool can greatly enhance the quality of your job. You can also benefit from lower noise and vibration. Flap discs can lead you to a world of new applications, while helping you achieve new levels of efficiency and effectiveness.

Purchasing Your Flap Discs

When it comes to purchasing flap discs, you have plenty of options. However, a reputable company that cares about you and your project will help you experience a better result. You should also feel comfortable asking for samples when you’re trying new tools like a flap disc.

National Abrasives, Inc. has a large variety of tools, accessories and supplies to meet your immediate needs and your needs in the future. We’re a family owned company that offers same-day shipping and discounted pricing for bulk orders. Browse our large selection of brand-name flap discs, including Walter Abrasives flap discs, along with angle and bench grinder tools and accessories. If you have any questions, our team can guide you to the right tool for your specific job. Contact us today to get started!

Flap Discs for Angle Grinder

It always pays to use the right tools for the job. When working with metal, it becomes very important to use tools that are safe and effective. If you are engaging in metal grinding or finishing, then you will want to consider using a flap disc for your angle grinder.

What is a Flap Disc for Angle Grinder?

A flap disc is an abrasive disc made of small sheets of overlapping sandpapers arranged in a circular shape. The layered overlapping segments or “flaps” have small grains of abrasives such as aluminum oxide. These abrasive grains are attached to a backing cloth which is normally made from polyester, cotton, or blended material.

The cloth is cut into smaller sections or flaps and layered across the disc. This is where the flap disc gets its name. These flaps are glued onto a backing plate made of plastic or fiberglass.

How the disc itself performs when being used will depend on the type of abrasive material used and its grit size. This is an important step because the selection of abrasive material and grit size will determine the effectiveness of the finishing or grinding you intend to do on the metal.

You can select between single and high-density flap discs. The high-density versions have more cloth which makes them thicker, and they will last longer compared to the single versions. You can also select the size of the flap discs which range from two to seven inches in diameter. Many people use the two-inch disc to replace blending discs as they tend to be far more durable.

Advantages of Flap Discs

The main benefit of using a flap disc is its low wear and ability to apply varying degrees of finish with the same disc. Each flap on the disc touches the workpiece surface at a different angle. This not only reduces swirl marks but also prevents repetitive damage to the surface, which is common with flat sanders such as palm sander.

In the case of a flat sanding sheet, you may have to replace it when a portion of the sanding surface is damaged. With the flap disc, the wear of abrasive particles is spread across several flaps; and damage to one flap doesn’t affect the performance of the disc.

During grinding the highest point of the flaps touch the workpiece. As you continue to do the machining, the abrasive grains here will get depleted and the fresh abrasives of the flap behind them will be exposed. This process continuous and enables you to grind without losing the quality of cutting and also extends the life of the disc.

flap, discs, angle, grinder

The grinding wheel on an angle grinder is aggressive and can cause gouging and digging. While the flap discs can remove a lot of material quickly, it is much more forgiving than grinding.


The downside is that a flap disc is not well suited to work on uneven surfaces. This is because the flap disc uses cloth that can catch on the uneven surface and tear, resulting in having to change out the disc which only costs you more money. In that case, you will need a polishing disc or a die grinder to do the job.

Flap Disc Uses

What are flap discs used for?

Flap discs are primarily used for metalworking for grinding, blending, clean up welds, chamfering, etc. They can be used for finishing metals by quickly removing burrs and producing a smooth finish on the edges. Flap discs are also used to remove paint, rust, and corrosion from metal surfaces.

Although not as aggressive as a grinding wheel, the flap disc can remove a lot of material than one would imagine. The first time I used a 40grit flap disc on an angle grinder, I was surprised how quickly it removed the excess stock.


High-density flap discs are excellent for contouring, blending, matching, and finishing. When you apply pressure, the overlapping flaps compress to form a stronger disc and removing a higher amount of material. With the same disc, if you apply light pressure, it can be used for finishing.

Cleaning up Welds

This is perhaps one of the most common uses of these discs. Since you can grind and finish the weld with the sample flap disc, it saves you a lot of time. This also means that you spend less money to get the same result if you were to purchase a grinding and finishing disc.

Paint and Scale Removal

It is also an excellent tool to remove rust and corrosion scales, heat treatment scales, etc. You can use a flap disc with an angle grinder to clean old paint, rust, and other materials without damaging the surface underneath. It can also be utilized to remove stickers or other adhesive materials from surfaces like concrete or metal.

Sanding Wood

Although it is mainly a metalworking tool, you can use a flap disc for sanding wood and preparation for refinishing. Here is a detailed guide where I discussed the methods of using an angle grinder as a sander.


This type of abrasive disc also works well for auto body repair and restoration work. Since these discs are much more forgiving you can use them for grinding and finishing the car’s metal body and parts.

Types of Flap Discs

Before you buy the discs, you should know about the different types of flap discs. The two main types of flap discs are Type 27 and Type 29.

Type 27 vs. Type 29 Flap Discs

The differences between the Type 27 and Type 29 flap discs are in the angle. The type 27 disc has a flat face whereas the type 29 flap disc has a conical shape with flaps angled towards the edges. The difference is subtle, but important since they are designed for different uses. That is why you should carefully consider the work being performed before choosing which one is right for the job.

The Type 27 is a flat disc and is best used for finishing applications where the angle of use will be from 0 to 15 degrees. You can also do some mild grinding with the Type 27 disc at this low angle, but this is more of a finishing disc when most of the grinding has been completed.

The Type 29 has a beveled edge and is better for high angle grinding, which is normally between 15 and 25 degrees. This type of disc is best used for grinding purposes, especially on tough metal or when a considerable amount of grinding needs to be done.

Abrasive Types

There are different abrasive types that you will need to consider before making a purchase.

Aluminum Oxide: This is the traditional abrasive that was first widely used on flap discs. Today, aluminum oxide is most common on low-priced flap discs.

Zirconia Alumina: Another very popular type of grain used on flap discs, zirconia alumina is a blend of both zirconia and aluminum oxide grains. The result is a disc that is more versatile compared to the standard aluminum oxide, but it is more heat-resistant, durable, and has self-sharpening grains so that it does not wear out nearly as quickly.

Ceramic Alumina: These are the most expensive of the three types of grains, but they are also the most durable. Because the grains on the disc break apart into micro-fractures, they provide a continually sharp edge for grinding and finishing. This means that the ceramic alumina flap disc has longer tool life and needs to be replaced less often. This improves productivity.

However, the price of ceramic alumina discs can be steep. So it may be more economical to purchase a cheaper type depending on the requirements of your job. If you are only working for a short time or intermittently on different types of grinding or finishing work, then the zirconia alumina or aluminum oxide may be a better choice. But if you are a professional or are doing long-term work, then investing in a ceramic alumina flap disc is probably the best choice.

Ceramic and Zirconia Alumina Blend: This as the name suggests is a blend of both ceramic and zirconia. It provides the best of both substances for all-purpose use. The main advantage is that it grinds with less effort compared to all other types. However, it is also expensive, so you will need to look at your budget before you decide.

Grit Size

The size of the abrasive grain determines the quality of finish. A higher the grit number means finer abrasive grains and hence smoother finish.

Grit Size Common Uses
24 – 40 grit Heavy Stock Removal
40 – 60 grit Grinding, Weld clean-up
80 grit discs Cleaning, Sanding
120 git and above Finishing

Flap Disc for Metal

You can use all four types of flap discs for metal. This is because the flap disc is primarily designed to both grind and finish metal. You will need to decide what type and grit to use in getting the results that you desire. Be sure that you are placing the flap disc at the proper angle when grinding or finishing.

Flap Disc for Wood

Although mostly associated with metal, the flap disc is perfect for grinding or sanding wood. It will not provide a finish like it does for metal, but it can sand down wood with great efficiency. You should choose a coarser grit version that can really grind into the wood to remove imperfections. However, if you are prepping wood for painting, then you can use a finer grit to lightly take off the surface.

Keep in mind that it will be very difficult to get a perfectly flat face on the lumber with an angle grinder. For flattening wood, I strongly recommend you use a belt sander or a drum sander.

Flap Disc for Paint Removal

The best type of flap disc is arguably the Type 27 that can be used at a nearly flat angle with fine grit. This will allow the flap disc to take off the paint while not digging into the surface too much.

As mentioned before, there are some grit components that work better than others. In particular, the ceramic and zirconia alumina are quite good and will last a long time with proper use. But they are also expensive, particularly the ceramic and the blend. If you are a professional who will use the flap discs regularly, then you probably want to invest in the more expensive versions.

If you are a woodworker or hobbyist who occasionally delves into grinding or finishing materials, then you might consider a cheaper version such as aluminum oxide. In addition, cheap flap discs may also be used by professionals if they believe that the additional price may be worth the purchase.

How to Use a Flap Disc?

Select the Right Gran and Grit Size

As I explained earlier you can use a single flap disc to remove material (grinding) and finish it (sanding) by varying the pressure applied on the workpiece. A flap disc is perhaps the only sanding device with which you can achieve higher grades of finish with lower grit wheels. That means you can use a 40grit disc and with delicate touches, you can achieve the finish of 60-grade sandpaper.

However, if you need to remove a lot of stock it is better to start with a coarse grain disc. When you are finishing the material, you can switch to a finer grit to complete the job.

Clamp the Disc and Check the Rotation.

This step is self-explanatory. Before you switch on the grinder, rotate the disc with your hand to ensure that it spins smoothly.


Adjust the safety guard on the grinder such that the direction of the sparks will be away from your body. Make sure that the guard will not cause hindrance as you keep moving the grinder with the disc spinning at high speed.


Start the angle grinder and slowly bring the flap disc onto the workpiece to be ground or polished. To ensure that you use a flap disc properly, it must be held at the proper angle with the right amount of pressure applied to achieve the results that you desire. If you grind at an angle too steep, it may use up the edge of the disc rather quickly and cause it to wear out at an accelerated rate. Once you do this, the flap disc will have to be discarded.

The wrong angle will not remove the excess material in the proper manner. And if you are trying to grind away unwanted material, the wrong angle may only ruin the project. If you want to complete the work faster, it is better to stick to a proper angle and use a coarser grit flap disc which will take away more material.

Thin Sheets

You must be careful when using the flap disc on thin sheet metals for finishing purposes. The material removal rate could be more than what you expect and could create holes in thin sheets.

Too little pressure is placed on the flap disc and it will take longer for it to achieve the desired results. While applying too much pressure may cause the disc to slip or that you take away more material than desired. Too much pressure can also wear away the grains on the disc faster, causing it to create gouges or burn marks in the material.

Overall, flap discs are quite handy and useful in finishing metal and grinding metal, wood, and other hard materials. While angle grinders are arguably not the best devices for grinding and finishing, they are quite handy, portable, and can fill in adequately when needed.

  • What is a Flap Disc for Angle Grinder?
  • Advantages of Flap Discs
  • Cons
  • Stock Removal
  • Contouring
  • Cleaning up Welds
  • Paint and Scale Removal
  • Sanding Wood
  • Automobile
  • Type 27 vs. Type 29 Flap Discs
  • Abrasive Types
  • Grit Size
  • Flap Disc for Metal
  • Flap Disc for Wood
  • Flap Disc for Paint Removal
  • Select the Right Gran and Grit Size
  • Clamp the Disc and Check the Rotation.
  • Safety
  • Grinding
  • Thin Sheets

Grinding Wheel vs Flap Disc vs Sanding Disc: What Is the Difference?

When you are using your angle grinder for DIY projects, one of the most important considerations is which type of attachment you are going to use. Grinding wheels, flap discs and sanding discs are among the most common grinder attachments yet they are used for very different types of projects.

Typical uses of a grinding wheel include removal of material while a flap disc is the first choice for abrading metal. If you need to sand wood or other material with your angle grinder, a sanding disc is the right attachment to use, although the results would mostly be second to those of an actual sander.

Read on to learn the details of each of these grinder attachments. Read this article on how to use a grinder to learn more about cutting tiles and sanding wood or steel.

What Are the Different Uses of Grinding Wheels, Flap Discs and Sanding Discs?

Although all these types of attachment are for use with an angle grinder, the outcomes and the materials they can deal with are different. The following table summarizes the differences in their use.

Grinding wheel Flap disc Sanding disc
Processing and results Surface removal, trimming and cleaning; Saw-type wheels produce cuts on different material Abrasion and Finishing of surfaces Sanding and finishing surfaces
Material Removing metal fast; MIG welding; wood; stone and concrete Metal Wood; metal; concrete, stone and other material (special discs needed)
Typical uses Trimming surfaces quickly; Cutting workpieces (saw-type wheels) Shaping metal; A slower, less spark-producing alternative to grinding wheels for weld deposits and slag removal Sanding and finishing surfaces if no advanced smoothness is required (otherwise, a sander would be the better choice)
Price level (per piece) Check on Amazon Check on Amazon Check on Amazon

Move forward to the next sections to learn more about the characteristics of each of these attachment types as well as practical tips for their uses.

Grinding Wheels

Grinding Wheels come in a variety of sizes and thicknesses. Make sure the wheels you purchase are the correct size so they fit into your angle grinder’s guard. They should also be about a quarter of an inch thick. Any thinner than this and you may be looking at a cutting disk instead of a grinding disk.

What Are Grinding Wheels Used For?

A standard grinding wheel is designed for quickly removing metal. Use it for preparing metal for MIG welding, clean and trim down old welds and removing welding slag. They are available in different sized Grits just like sandpaper. Lower numbered grits are coarser and remove metal quicker while higher grits are for finishing work, cleaning and polishing. A higher grit grinding wheel may take a bit longer to finish the job than a lower sized one but it will be safer and more comfortable as fewer large sparks will be produced.

Low grit grinding wheels produce large and very hot sparks. If these land on your skin, they are mildly uncomfortable, rather like a small bee sting. However, they are hot enough to melt some clothing, especially man-made fibers and, if landing on glass, they can embed into the glass. Eye protection or a face shield should always be used.

Over time, grinding disks will gradually wear down in size and they should be replaced appropriately. If a disk is misused or jumps during use, it may become damaged and should be immediately replaced for safety. Cheaper disks can become damaged then fail completely spreading flying pieces of disc into the air. This can cause damage and be very dangerous if safety equipment is not being worn.

Special grinder disks with chain saw type blades are available for specifically cutting and shaping of wood. There are also available grinder disks with teeth on the outer edge which are also intended for woodworking.

Flap Discs

Flap Disks are abrasive disks made from small flaps of overlapping abrasive covered cloth formed in the shape of a wheel. Flap disks are more efficient in their use than using a flat abrasive paper in that flap disks wear from the outside edge in distributing the wear evenly across the entire disk. The length of each flap can be worn down completely before the disk needs to be replaced so the wheel is useful as the flaps erode, unlike a flat abrasive sheet which must be discarded even if only a small part of the sheet is eroded away. Flap disks last up to 25 times longer than fiber disks

The advantages of flap disks during use are that each separate flap attacks the workpiece at a very slightly different angle which also varies with the angle of the grinder. This avoids the common issues with flat abrasive paper that can easily produce identical repeated scratches in the work.

What Are Flap Discs Used For?

They are used to shape and contour metal and can be used as an alternative to grinding wheels for removing weld deposits and slag. They remove metal slower and produce smaller sparks than grinding wheels. Flap disks are less robust than grinding wheels and can be damaged easily if care is not taken. Because they consist of only pieces of abrasive covered fabric glued to a solid backing by resin, there are fewer pieces that may become damaged and fly off so are generally safer than grinding wheels. They are lighter than grinding wheels so produce less vibration and are easier to operate.

Sanding Discs

Sanding discs with different grits.Check on Amazon.

Angle grinders can be used for sanding both wood and metal but also other types of material. When you need to sand a lot of wood away, a sanding disk attachment is ideal. However, for wood, angle grinder rotary sanding does not produce such a good finish as is obtained with a random orbital sander or an orbital sander for wood but it is usually acceptable for many DIY jobs. To sand rough wood smooth, start with a low grit sandpaper and work your way up gently stroking the angle grinder over the wood’s surface each time.

How Can You Use Sanding Discs?

The general method of attaching sanding disks to angle grinders is by use of a soft foam pad with Velcro backing. The pad has an attachment that screws onto the angle grinder screw and Velcro-backed sanding disks attach to the front plate. When the sanding disks are used up and you need to change them, it is just a simple task of pulling the two Velcro surfaces apart and attaching a new one.

Sanding disks are available in all grit sizes you could think of. They are meant for use during the end of a task or project for finishing off prior to polishing. However, they are not ideal for heavy use or for removal of a lot of metal.

Using sanding disks is generally the safest type of angle grinder attachment because in the case of a failure of the disk, only paper will be ejected. However, sanding disks used on steel can still produce a lot of sparks especially if a low grit is used. Safety precautions should still be followed including eye protection, a face shield and protective gloves.

Sanding disks are not recommended to tidy welds or remove slag as this may damage the disk quickly. They are designed for use on flat surfaces for polishing, removal of rust and paint and for finishing, not only for metal but also for plastics, ceramics and glass. With glass, extra care and safety precautions should be made to avoid injury.

Note that harder materials, such as steel, glass or concrete, require special sanding discs. They come with harder and more durable abrasives, e.g. of diamond tool.


An angle grinder is probably one of the most versatile handheld tools if you use it with attachments that fit for the particular purpose. If you need to remove and trim material, you will want to go for grinding wheels. Flap discs are ideal for grinding metal surfaces, and they also produce less sparks than grinding wheels. Sanding discs are available for a variety of materials and they are generally used for sanding and finishing.

Make sure you read our article on how to use a grinder before you start

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Zirconium and Ceramic Flap Discs. Which suits your grinding needs?

Choosing the right tools and materials are the most critical factors when it comes to the time it takes to finish a project, and ultimately, the quality of work. Nowhere is that more apparent than in the grinding disc you use to finish your project.

Of course, you’re looking for a high-quality product that is affordable, reliable, durable, and will get the job done the way you want it, every time. So how do you know which one to choose to get the job done right? Let’s break down the differences between zirconium discs and ceramic discs, by looking at the characteristics of each, and determining which disc best suits your needs.

Zirconium, or zirconia alumina, is a mix of zirconium dioxide and aluminum oxide.It is most often used in metal fabrication shops as it is an excellent choice when it comes to removing welds and blending on hard metals, including carbon steel, stainless steel, and titanium.

Zirconium performs well under higher pressure, while retaining a consistent cut rate and surface finish through the life of the disc. Zirconium will outlast and outperform aluminum oxide, especially when it comes to aggressive grinding.

The Ins and Outs of Ceramic Discs

Ceramic grain is a synthetic abrasive that is extremely hard and durable. It has a longer lifespan than zirconium, which means even at a higher cost, ceramic could save you money in the long run. Ceramic flap discs are ideal when it comes to grinding most metals and work best with moderate pressure.

The shape and structure of the ceramic minerals give the discs their sharp grinding edge. It is also how it maintains its cutting power and stability over use.Ceramic is used to manufacture many different types of abrasive discs, including fiber discs, and flap discs.

Zirconium Discs vs. Ceramic Discs

Choosing between these two types of abrasives comes down to two questions:

Both zirconium and ceramic discs are exceptional choices depending on your project needs. Here’s a cheat sheet to remember each type when it comes to your next project:

The New Rex-Cut MetalPro Line

In recognizing the value in each type of abrasive tool, Rex-Cut is releasing the new MetalPro line of coated abrasive products.

Rex-Cut, known for its quality products and unmatched level of service, is constantly striving to bring affordable, reliable, and durable products to help fabricators get the job done. It’s why we’re launching the MetalPro Ceramic Flap Disc and the MetalPro Zirc Flap Disc.

For more information about the Rex-Cut MetalPro Ceramic Flap Disc and the MetalPro Zirc Flap Disc, contact us today.

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