Flap Discs Vs Grinding Discs

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Angle grinders will either use flap discs or grinding discs when trying to achieve a unique shape on metal. Nevertheless, they have relevant differences which can help you in determining how and when they will be used appropriately. Generally, most people prefer to use grinding discs for removing materials, however, you can also use them for surface preparation. They can quickly even out surfaces compared to flap discs. Unfortunately, they cannot provide you the smoothest finish.

On the other hand, flap discs can also be used for shaping metal, and at the same time, they can give you a smooth and even surface. Below, we are going to discuss more about their differences to help you decide which is the best abrasive disc to attach to your grinder. After knowing what you are looking for, you can start searching for them on the internet. Be sure to choose high-performance products that can last longer so you get more value for your money.

What Are Grinding Discs and When Should You Use Them?

Grinding discs are primarily used for grinding away materials on stone and metal. They are often used for grinding welds, as well as metal edge preparation for welding. Grinding discs are the most suitable option if your goal is high stock removal. They have a thick coarse appearance and can provide uneven results. However, they can instantly remove materials so that you can get the job done quickly.

What Are Flap Discs and When Should You Use Them?

Aside from grinding metal, flap discs can also be used for blending, deburring, and finishing. In other words, flap discs are more versatile. They are named flap discs due to their appearance. It features a lot of overlapping layers of abrasive on its surface. These flaps are responsible for helping the discs last longer.

Flap discs differ in sizes, shapes, and grits, making it too confusing. If you are looking for the best-performing product, then you should choose ceramic flap discs. They can be used on all types of metal including aluminum. Flap discs might be slow at removing stock; however, they can provide you with a smoother even finish.

This is perfect if you are planning to paint the metal. Aside from this, flap discs have other benefits other than grinding discs with regards to the operation and outcomes. If you want to use flap discs for stock elimination, then you should choose something that has a conical shape. This is because this shape can greatly help you in removing materials more quickly.

What are the Benefits of Flap Discs?

Flap discs can grind faster. Ceramic flap discs can quickly grind weld preps on sheet and steel plates. They offer cooler cutting, which means that there are a few incidences of re-work. Generally, grinding discs are aggressive and produce a rough finish. Also, there are chances that the metal could get damaged when using grinding discs. However, if you choose flap discs, then you can guarantee a smoother consistent finish.

Most people find it comfortable to work with flap discs since it is quieter and has fewer vibrations. Additionally, you don’t have to exert more effort in order to achieve the desired results that you want. Most of all, flap discs are a cost-effective option because they can help you in reducing your labor costs.

Which is Better – Flap Discs Vs Grinding Discs?

Actually, it does not have to be an either-or question. Both of them have their own advantages and some crossover. You can even use both of them so that you can achieve the best results for your project. Typically, you can use grinding discs for faster stock removal. Afterward, flap discs are used for a smoother and well-blended finish.

If you are not concerned with the finish, then you can simply use a grinding disc since it can provide you with quicker results. However, if you would like to perform a complete grinding and polishing job simultaneously, then a flap disc is the best option. While it might take longer to finish, flap discs are very comfortable to work with even if you are working for a period of time.

Which One Should I Choose for Heavy Grinding – Flap Discs or Grinding Discs?

It is strongly recommended that you use a 40 grit Ceramic flap disc. The reason behind this is that they can cut faster, providing you with a better finish. They also have much less vibration compared to grinding discs. This is specifically for weld prep grinding jobs, where you have to grind away mill scale. Keep in mind that zirconia flap discs have inadequate cutting power.

Furthermore, it will take more time to grind the entire job when using grinding discs since you can only work on a limited area. That is why the best choice would be ceramic flap discs since you can grind over a bigger surface area. They can cut through the mill scale faster and provide you with a better finish. Best of all, you can save a lot on the welding wire costs.

What Are Sanding Discs?

When doing DIY projects, one of the most useful tools is an angle grinder. However, it is also important to consider what type of attachment you need to use. Some of the most common grinder attachments are flap discs, grinding wheels, and sanding discs. They are valuable in different types of projects.

Grinding wheels are commonly used for removing material while flap discs are the best choice for scraping metal. If you are using your angle grinder for sanding wood or other material, then the appropriate attachment to use is a sanding disc. However, the results of these are likely second to those of a real actual sander.

Sanding discs have different grits. Angle grinders are very useful for sanding both metal and wood. However, if you want to sand several kinds of wood, then it would be ideal to attach sanding discs. Angle grinder rotary sanding is the best option for your DIY jobs which use wood.

But if you want to achieve a good finish, then you should use an orbital sander or a random orbital sander for wood. If you are sanding a rough wood surface, then you can make it smoother by starting with low grit sandpaper. When using the angle grinder, try to work your way up by doing some gentle strokes over the wood’s surface.

How to Use Sanding Discs

Generally, sanding discs are attached to angle grinders by using a soft foam pad together with Velcro backing. The foam pad comes with an attachment that will be screwed into the angle grinder. At the same time, the Velcro-backed sanding disks will be affixed to the front plate. Once the sanding disks are already used up and need to be changed, then this can be done by simply pulling out the two Velcro surfaces apart and affixing a new one.

You can avail of sanding disks in almost all grit sizes. They are meant to be used after a task or project is completed. Sanding disks are designed to finish off before polishing the material. Nevertheless, they are not intended for the removal of several metals or for heavy use.

Among the different types of angle grinder attachments, sanding disks are typically the safest. This is because, if there is a malfunction of the disk, then the paper will be ejected. But if sanding disks are used on steel, then it could generate several sparks, especially if you are using a low grit. That is why it is always important to follow safety precautions, such as using protective gloves, a face shield, and eye protection.

Sanding disks are not designed for removing slag or cleaning welds since they could damage the disk really quickly. They are meant for use on flat surfaces for finishing or for removing paint and rust. Aside from metal, they can also be used for glass, ceramics, and plastics. Extra care should be observed when used on glass. Also, safety precautions must be followed to prevent any injuries. Take note that when working on harder materials such as concrete, glass, or steel, you may need a special type of sanding disc. They have stronger and more durable abrasives.


Angle grinders are considered one of the most versatile handheld tools, as long as you are using the appropriate attachments suitable for a particular purpose. If you want to remove and tidy up material, then you should choose grinding wheels. However, when grinding metal surfaces, it is best to use flap discs since they generate minimal sparks than grinding wheels.  Commonly, sanding discs can be used for different materials. Usually, they are used for finishing and sanding.

Sparks and Arcs offer various types of grinding wheels, cutting wheels, flap discs, flap wheels, and other types of abrasives. We are also selling angle grinders, chop saw, belt sanders, etc. For more information about our products, you can get in touch with us at 877-95-SPARK (877-957-7275), or you can send us an email at CS@sparksandarcs.com.

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