Learn How to Cut Fire Brick For Your Next Masonry Project

Cutting any sort of stone or brick seems pretty intimidating. Add fire to the name, and it’s easy to feel like the project is way over your head. Fortunately, that couldn’t be farther from the truth. With just a bit of know-how and a few regularly available tools, the question of how to cut firebrick is an easy one to answer.

Today, we’ll cover everything you need to know about cutting firebrick, so you can take your masonry project to the next level without the help of the pros.

What You’ll Need

Today, we’re going to cover the “old fashioned” way of doing things as well as a more power tool-centric version (woo!). Either way, you won’t need much in the way of tools.

If you’re planning on going the old-fashioned route, all you’ll need is:

  • Masonry chisel
  • Short sledgehammer (although any hammer will do in a pinch)
  • Gloves
  • Safety goggles
  • Face mask
  • Ruler or tape measure
  • Chalk

For more precise cuts, you’ll want to enlist the help of a saw. In that case, instead of a masonry chisel and short sledgehammer, you’ll need your trusty miter saw.

Step I: Measuring

The first and arguably most important step is to measure your brick, so you can cut it precisely. Once you’ve measured where you need to cut using either a ruler or tape measure, you’ll want to use a bit of chalk to mark where you’ll be cutting. This is particularly important if you’re using a saw to make your cut.

Step II: Scoring the Brick

If you’re going to be using a saw to cut your brick, you can skip straight to step IIA. But, if you’ll be using a hammer and chisel to break your brick, you’ll want to score the brick all the way around before getting started.

First, you’ll want to put your gloves on. Wearing gloves help to protect your hands, but they also help to limit the vibration of the chisel as you strike it with the hammer, which greatly reduces hand fatigue.

To score the brick, start with the side you’ve placed your mark on. Place the brick on a flat, level surface. Place the chisel over where you’ve marked on the brick, and gently strike the chisel with the hammer. Continue to do this until you see a visible mark from the chisel in the brick.

Repeat this process around all four sides of your firebrick. Scoring the brick will create a precise crack around the entire outer surface of the brick. This will help you achieve a much more uniform break in your firebrick.

Step III: Breaking the Brick

Once the brick is completely scored, you can begin swinging to break the brick. You don’t have to swing for the fences. Let the hammer do its job and be sure to follow through on all your swings to allow the energy from the hammer to transfer to the chisel and the brick.

Take special care to ensure that the chisel is perfectly straight and that you’re contacting the center of the chisel’s handle with each swing of the hammer. After a few forceful blows, the brick should break exactly where you want it to.

Keep in mind that firebrick is a bit more difficult to break than regular masonry bricks. If you’re having trouble breaking the brick, just repeat the scoring process.

Step IIA: Sawing Through The Brick

Using a saw to cut through the brick is a surefire way to guarantee a perfect precision cut for your project. It’s also the only way to cut firebrick if you need to make angled cuts. When it comes to how to cut firebrick with a miter saw, you’ll find it’s surprisingly easy to do. It’s also more practical than breaking the brick by hand, especially if you have multiple bricks to cut.

Before you make your cut, you may want to consider soaking your brick in water for about two minutes (or until you stop seeing air bubbles coming from the brick.) This will help to dramatically cut down on brick dust, and it’s especially helpful if you’re cutting indoors. Let the bricks dry for about five minutes prior to cutting.

There are several different saws that will make quick work of this job. Regardless of the saw you choose, it’s critical that you use a masonry blade to do your cutting. Masonry blades are specially designed for brickwork, and they provide the best cut for this application.

To cut the brick, take your brick with the chalk measurement facing up, place the brick against the fence, and slowly and carefully cut through the firebrick.

Final Word

While it may seem intimidating at first, learning how to cut firebrick is actually quite easy. For centuries, masons have relied on a hammer and chisel for all their cutting needs. More modern craftsman tends to cut their firebrick using a saw. Whichever method you opt for, you should be able to achieve great results on your next project by following these tips.

About Gus Donaldson

I built houses for over 30 years and recently retired. I've made lots of mistakes and hopefully teach you not to make the same ones. I still love to build and have a garage workshop that I use for hobby projects like the walnut bookshelf I made for my wife. I like to write and let people know that working with your hands and tools does not need to be intimidating.

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