Grinding Concrete with Angle Grinder: Steps for a Smoother Finish

Angle grinders are incredibly versatile power tools that can cut through materials using abrasive or diamond blades. 

Not only that, they also have an incredible ability to grind concrete to create a smoother finish.

If you’ve been searching for the right tool to level concrete and wondering if an angle grinder is the best option, this article is here to help! 

The angle grinder is an excellent choice for several reasons: it is small, mobile, versatile, and inexpensive – meaning it may just be the best tool to assist you with your concrete grinding project.

In this article, we’ll go over:

  • The tools that are required for this project
  • A step-by-step guide to grinding concrete with angle grinder
  • Advantages and disadvantages of grinding concrete with an angle grinder
  • Top tips for smoothing concrete.

Let’s get grinding!

What Tools Are Needed?

Tools for grinding

In terms of tools, the most important will be the grinder and PPE. However, it’s ultimately more complex than just these two essentials. 

You’ll also need the following before you begin grinding concrete: 

  • A full-face respiratory protective mask that will protect your lungs from hazardous airborne particles created when the concrete is ground
  • You may also want to wear professional protective knee pads, as you’ll kneel on a concrete floor for long periods
  • National Institute of Occupational Safety and Health approved standard anti-fog safety glasses. These need to fit safely and snugly across your face
  • A portable heavy-duty wet/dry vacuum with a power cord that gives the user the best mobility around the site, along with a large water capacity
  • A surface grinder dust shroud that will fit the size of your angle grinder with a quick-release switch
  • Diamond polishing pads that work for both wet/dry are the most ideal when polishing stone slab surfaces
  • A grunty pressure washer is also required; we recommend hiring one for the time you need. 

Finally, the most essential tool is the angle grinder! We recommend getting one with variable speed drive settings at a minimum of 10,000 RPM.

Step-by-Step Guide to Grinding Concrete with Angle Grinder 

Let’s get started! Once you’ve gathered all the mandatory equipment and protective gear, it’s time to smooth out the concrete. 

Below, I will outline the step-by-step process of grinding concrete most efficiently:

Step 1: Start by cleaning the surface

The first step is to ensure the floor area you are working on is prepared and cleaned correctly. To do this, vacuum and mop the floor; if the site is in disrepair, you can use the pressure washer to clean the surface more effectively. 

Step 2: Prepare the Angle Grinder 

Once the area has been cleaned to the best of your ability, run an extension lead with surge protection for the wet/dry vacuum and angle grinder (if it’s not cordless). 

Following that, connect the dust shroud to the angle grinder. This must be fitted securely to the grinder by tightening the clamp on the suction hood and locking the cover in place!

Next, prepare and connect the vacuum nozzle to the vacuum adapter on the dust shroud, and then to the wet/dry vacuum inlet. 

Now that you are keeping the power disconnected to the angle grinder, begin fitting the wheel to the grinder. The best wheel to start with is a diamond polishing pad. 

Step 3: Get grinding!

Now that everything has been prepared and connected, it’s time to put on all your safety equipment. This means fitting your mask, gloves, and earplugs. 

After you’ve put everything on properly, it’s time to start smoothing the surface area! 

Start by working the angle grinder around the perimeter of the site you’re working on. It’s best to work from the outside in circular motions. 

Once the perimeter edges of the floor space have been smoothed, begin working inwards. Keep manipulating the angle grinder in circular motions, as this will offer the highest level of consistency. 

Step 4: Correct any imperfections 

Now that a large surface area has been smoothed over, an untouched concrete section around the perimeter has been created. 

This will be caused by the dust-shroud plastic lip, which obstructs the grinding wheel from smoothing the surface close to the wall. 

To correct any imperfections, we recommend you remove the dust shroud from the angle grinder and review the sections closely. 

Remember, if you’re angle grinding without the dust shroud, ensure your mask is on correctly and your vacuum is near the grinder!

Is Grinding Concrete With an Angle Grinder a Good Idea? 

An angle grinder can be a suitable tool if you have a rough concrete deck or concrete floors that need to be leveled. 

The grinder is a reliable tool that efficiently smooths out uneven concrete surfaces. Using this tool, you can remove imperfections and create a nice, smooth, and level surface.

The Advantages of Grinding Concrete with Angle Grinder

Angle Grinder for Concrete Grinding

Versatility 

Angle grinders are incredibly versatile and can be used for several different jobs, as they can be used with a wide range of angle grinder discs. 

When grinding, all you have to do is use the proper attachment! You can then begin on different jobs without needing several other tools.

Portability

Angle grinders are also incredibly portable, which makes them easy to handle.

While they aren’t hand tools, they’re built to be easy to carry and maneuver on the job site. 

You can run a grinder comfortably and securely with both hands without concern for losing control, even at high speeds. 

Power

The best angle grinders need to be powerful enough for more demanding jobs. 

 It’s also vital to ensure you have all the correct attachments before you begin rather than just relying on the grinder’s motor to give you enough juice to grind, cut, and remove materials. 

We do recommend angle grinders with a speed of at least 10,000 RPM, as they’ll give you the best power for grinding.

The Disadvantages of Grinding Concrete with Angle Grinder

Angle grinders, while having the ability to cut concrete, aren’t always the best tool for the job. Below, the most significant disadvantages of using this tool will be outlined: 

Size 

Considering angle grinders use blades up to seven inches in diameter, it can take a considerable amount of time to level an entire concrete floor. We recommend a floor grinder to work on a whole floor area. 

Comfort 

When grinding a floor with an angle grinder, you will be on your hands and knees for long periods. 

If you’re looking to smooth over a floor, it is recommended to use a walk-behind grinding machine for increased comfort. 

Efficiency 

Most angle grinders do not come with a wet attachment, as they are typically made for dry use. 

These tools cannot be cooled with water, and as such, angle grinders wear the diamond blades down quickly when cutting concrete. 

However, there are some grinders out there that are explicitly made for concrete grinding with water attachments.

What Types of Projects are Angle Grinders Suitable for?

Types of Projects are Angle Grinders Suitable for

Cutting Tile, Stone, and Concrete 

The primary use of angle grinders is primarily focused on working with copper, iron, steel, and other metals. 

However, these grinders can cut through masonry materials such as tile, stone, brick, and concrete as well. 

To do so, switch out the metal cut-off disc for a masonry cutting wheel – allowing you to cut through these materials easily. 

Restore Cutting Edges 

Angle grinders can sharpen tools and restore the cutting edge to lawn mower blades, axes, and chisels. 

To do so, equip the angle grinder with an abrasive grinding disc and ensure the blade is secured correctly. 

Once connected, focus on controlling and steadying the movement of the grinder to restore edges.  

Cutting Out Old Mortar 

Angle grinders can help fix leaks, drafts, and insect infestations associated with old mortar outside the home. 

Removing mortar while not damaging the brick can be difficult, so using an angle grinder with a thick and abrasive grinding disc is essential. 

The disc can handle masonry work, which chips away at the mortar lines between the bricks. 

Cut Rods, Bars, and Bolts 

The angle grinder’s rapidly rotating disc doesn’t just smooth and polish!

It can also cut straight through metal. To cut through metal, change the abrasive grinding disc for a cut-off disc and choose the appropriate thickness. 

Thinner-sized discs make it easier to cut through metal as less material needs to be removed. 

Metal Cleaning 

The angle grinder can remove paint, rust, and lacquer from any metal surface. To do so, equip a plastic stripping disc or metal cleaning wheel to the grinder. 

These discs can remove chipped and peeling layers without damaging the metal underneath.

Tips For Smoothing Concrete With Angle Grinders

Choose among the best angle grinder models

It is essential to purchase the right angle grinder model based on your job at hand. You must choose the right size and power grinder in order to generate the best results and prevent injury!

The most common angle grinders for concrete are between four and seven inches. Further, you want to guarantee the motor can pull between 5-9 amps. 

Choose the right grinding wheel

When you’re selecting the correct grinding wheel, there are several factors to take into consideration. These include: 

  • What material will be grinding, and how hard is it? 
  • What stock needs to be removed from the material? 
  • What is the shape of the material and the surface finish? 
  • What type of power grinder is being used? 
  • What is the size and hardness of the grinding area? 

You will need to investigate all of these questions when determining which wheel to use; as a general rule of thumb, the more rigid the material, the softer the grade of the wheel. 

Use a good dust collection system

While you’re grinding, you may stir up a lot of dust in your work area which could lead to the accidental inhalation of silicone dust or construction materials. 

Ensure you always wear a face mask and have a vacuum and dust cover attached to the angle grinder to get rid of any particles. 

Make sure you use safety gear

When using the angle grinder and any other power tool, it is essential to have all the correct safety procedures in place as mentioned at the start of this article!

Make sure the guard on the grinder is always up and intact and that you’re using the tool in a safe environment. 

Also, ensure you wear gloves, safety glasses, and PPE, and take adequate breaks if you’re tired. 

Watch out for overheating

If you feel the angle grinder overheating or becoming too hot, turn it off immediately! It’s extremely important to allow the grinder time to cool down.

Conclusion 

As we’ve discussed in this article, angle grinders are incredibly versatile and powerful handheld tools. 

An angle grinder with the correct diamond blade can level and smoothen concrete very effectively. 

These tools are best for working on more intricate and smaller tasks where you can reach the area with no issues. 

Finally, remember that the angle grinder you use has sufficient power to go up against the concrete area you’re working on!

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Barry Gray

Hi, I’m Barry. I’ve loved woodworking and bringing things back to life for more years than I care to remember. I hope my passion for tools comes across loud and clear in everything you read here on The Tool Square.