How To Cut Cinder Block With An Angle Grinder – A Step-By-Step Guide

Are you planning a DIY project that involves cutting cinder blocks? If so, you’ll need the right tools for the job.

While a concrete saw is the most efficient tool for cutting through dense materials like cinder blocks, it can be expensive and difficult to use. Fortunately, an angle grinder can be a great alternative for smaller projects.

With the right blade and technique, you can make precise cuts in cinder blocks quickly and easily. In this article, we’ll walk you through the steps to safely and effectively cut cinder blocks with an angle grinder.

So grab your safety gear and let’s get started!

How To Cut Cinder Block With Angle Grinder

Step 1: Prepare Your Work Area

Before you start cutting, it’s important to prepare your work area. Make sure you have a clean, flat surface to work on and that there are no obstacles in your way.

You should also put on your safety gear, including safety goggles, a dust mask, and leather work gloves. Angle grinders can throw debris and create a lot of dust while cutting cinder blocks, so it’s important to protect yourself.

Step 2: Mark Your Cut

Using a tape measure and pencil, layout the cut on the cinder block. Draw a straight line across the block’s surface at the measurement marks with a pencil, using a carpenter’s square as a guide.

Step 3: Attach the Right Blade

Make sure you have the right blade for cutting through cinder blocks. A diamond saw blade is the best option for this task. It has diamond studs and ventilation channels that prevent concrete dust from collecting around the diamond studs and allow air to flow across and cool the blade.

Step 4: Start Cutting

Turn on the angle grinder and hold it so that its blade faces out and the guard faces up. When cutting, the blade will throw debris back toward the handle and operator. This protects the user if the angle grinder drops or binds in the cut — the blade will roll the grinder away from the user.

Score the cinder block’s surface along the pencil marks with the angle grinder’s blade. Work the blade back and forth across the pencil line until the blade creates a 1/8-inch deep groove. Repeat this on each pencil line.

Cut through the cinder block along the score marks with the angle grinder. If cutting straight lines completely across the block’s face, cut both outside edges before cutting the center of the line. If cutting a hole in the center of the cinder block, work the angle grinder’s blade through the center of each score mark. Once the blade penetrates the center of the score marks, work the blade to the corners of the hole.

Step 5: Finish Your Cut

Flip the cinder block over and finish any corner cuts or trim any excess concrete from your cut with an angle grinder on its reverse side. Trimming from this side protects your cinder block’s visible surface.

Safety First: Preparing For The Job

Before you begin cutting cinder blocks with an angle grinder, safety should be your top priority. Here are some safety tips to keep in mind:

1. Wear Protective Gear: Always wear safety goggles, a dust mask, and leather work gloves when using an angle grinder. This will protect you from flying debris and dust that can be harmful if inhaled.

2. Clear Your Work Area: Make sure your work area is clear of any obstacles and debris that could cause you to trip or fall while operating the angle grinder.

3. Choose the Right Blade: Use a diamond saw blade that is specifically designed for cutting through cinder blocks. This will ensure that you get the cleanest cut possible and prevent the blade from overheating.

4. Secure the Blade Guard: Make sure the blade guard is properly secured before starting the angle grinder. This will protect your hands from accidentally coming into contact with the blade.

5. Use Light Pressure: Avoid using downward pressure when cutting with an angle grinder. Instead, let the tool do the work for you and use light pressure to guide it along your cut line.

6. Keep Your Distance: Keep a safe distance from the blade while it’s in motion to avoid any accidents or injuries.

By following these safety guidelines, you can ensure that your cutting job goes smoothly and safely. Remember to always prioritize safety when working with power tools like angle grinders.

Choosing The Right Blade For Cutting Cinder Blocks

When it comes to cutting cinder blocks, choosing the right blade is crucial for achieving a clean and precise cut. As mentioned earlier, a diamond saw blade is the best option for cutting through cinder blocks. However, there are different types of diamond blades available, and it’s important to choose the right one for the job.

For cutting cinder blocks, a dry-cutting diamond blade with a segmented rim is recommended. This type of blade has specially designed segments that help to prevent overheating and ensure a smooth cut. The segmented rim allows for faster cutting and helps to reduce dust while cutting.

It’s important to note that wet-cutting blades are not recommended for cutting cinder blocks. This is because the water used to cool the blade can cause the cinder block to become too wet and soft, making it difficult to achieve a clean cut.

When selecting a diamond blade for cutting cinder blocks, consider the size of the blade as well. A larger blade will allow you to make longer cuts in one pass, while a smaller blade will be easier to maneuver and control for more intricate cuts.

Marking And Measuring The Cut

Marking and measuring the cut is a crucial step in cutting cinder blocks with an angle grinder. To begin, use a tape measure and pencil to outline the cut you will make on the cinder block. Draw a straight line across the surface of the block using a pencil and carpenter’s square as a guide. The measurement marks are the starting point for your cut.

It’s essential to clear the space around you where you’ll be cutting of any potential trip hazards. Make sure your workspace is clean and free of clutter. If you must work inside, make sure there is adequate ventilation to prevent dust buildup.

To create a clean cut using an angle grinder, it’s necessary to first mark the position of the line to cut using a straight edge and a pencil or chisel. After that, score the line with a chisel and make sure the resulting groove is deep enough to retain the blade. That way, the blade won’t have to worry about slipping.

Before starting your cut, make sure you can handle the angle grinder’s weight and grip. Check the grinder’s stability and make sure you can hold it comfortably with your dominant hand. Most grinders will have two handles to help keep the instrument steady.

Hold onto the grinder firmly with both hands until the blade has reached full speed, and then brace yourself for the strength to decrease gradually. Now drive the blade firmly into the cinder block. Do not apply too much pressure on the blade. To keep the blade from getting too hot, make a series of cuts of progressively greater depth.

Once you’re done using it, turn off your angle grinder at the wall. By following these steps carefully, you can safely and effectively cut cinder blocks with an angle grinder.

Setting Up The Angle Grinder For Cutting

Setting up your angle grinder correctly is crucial for achieving a precise and efficient cut through cinder blocks. Here are the steps to follow:

Step 1: Choose the Right Angle Grinder

Make sure you have the right angle grinder for the job. For cutting through cinder blocks, you’ll need an angle grinder with a motor of 5-9 amps and a blade size between 4-7 inches. The more power your angle grinder has, the better it will perform.

Step 2: Install the Diamond Saw Blade

Attach the diamond saw blade to your angle grinder. Make sure it’s installed securely and tightened properly.

Step 3: Adjust the Guard

Adjust the guard on your angle grinder so that it’s positioned correctly for the type of cut you’re making. The guard should be adjusted to protect your hands and face from debris while cutting.

Step 4: Secure Your Workpiece

Secure your cinder block in place using clamps or a vise. This will prevent it from moving while you’re cutting.

Step 5: Check Your Blade’s Direction

Make sure your blade is facing in the right direction. The blade should be facing outwards, away from you.

Step 6: Turn on Your Angle Grinder

Turn on your angle grinder and wait for it to reach full speed before starting to cut. This will ensure that you get a smooth and even cut.

By following these steps, you’ll be able to set up your angle grinder correctly and make a precise cut through cinder blocks. Remember to always wear your safety gear and take your time to avoid accidents.

Finishing Touches: Smoothing And Sanding The Cut Edge

After you have finished cutting your cinder block with an angle grinder, the cut edge may be rough and uneven. To make it smooth and even, you will need to sand it down. Here are the steps to follow:

Step 1: Choose Your Sandpaper

Choose a sandpaper with a grit of at least 120. You can use a sanding block or attach the sandpaper to your angle grinder using the jig described earlier in this article.

Step 2: Sand the Cut Edge

Run the sandpaper along the cut edge of the cinder block, applying moderate pressure. Make sure to keep the sandpaper moving and work evenly across the entire edge. You may need to use more than one sheet of sandpaper to complete the job.

Step 3: Smooth Out Any Imperfections

If there are any imperfections or rough spots on the cut edge, you can use a finer grit sandpaper to smooth them out. Start with a grit of 220 and work your way up to a grit of 400 or higher for a polished finish.

Step 4: Clean Up

Once you have finished sanding, clean up any debris or dust from your work area. You can use a damp cloth or vacuum to remove any remaining debris.

By following these steps, you can achieve a smooth and even cut edge on your cinder block. Remember to always wear safety gear when using an angle grinder and follow all manufacturer’s instructions for safe operation.