Using a miter saw to cut firebrick | tips, tools, techniques

Hit a snag here fellas. Both my miter saw and grinder blades have stopped cutting after 4/5 cuts each. Both tools are equipped with continuous edge diamond stone blades. An I using the wrong blades? I thought the continuous edge were for hard stone and segmented edge were for softer materials like concrete. Anyone have a recommendation on a blade that will give me the 10/15 cuts I have left?

This is what i use on firebrick. It is segmented, and so far has cut through over 50 brick without any signs of wear.

This is what it looks like on the saw.

Everyone’s technique is going to be different, but I will say that letting the blade do the work is especially important here. I do apply light pressure on the saw handle to make sure it doesn’t bounce back, and I’m rewarded with a cut that moves steadily through the piece “like butter.”

Hope this helps!

1 Like

Following up to help anyone else who has the same experience. As is usually the case, this came down to inexperience with cutting masonry. I’ve cut plenty of cinderblock (and hundreds of wood & metal studs) and had no idea how long it takes to cut high density firebrick. @bikerbudmatt, when I saw your comment about resting your hands on the handle just to keep the blade from popping up, I realized I must be doing it wrong. Sure enough, I just wasn’t being patient. Cut all my remaining bricks today, but it took about 10 minutes to get through each brick. But they came out perfect. What threw me was the very first firebrick with a new blade. The blade went through the brick in about 10 seconds. So that was my benchmark. Once it broke in and refused to cut each brick thereafter that fast, I freaked out. Turns out you just need to give it time. So for everyone else out there, don’t expect to slice through these bricks like a wood stud! Thanks again Matt!


Does adding water while cutting help at all?

Hi Tom,

Are you thinking spraying water on the brick while cutting them with a dry-saw? If so, probably not, and probably not a good idea.

Soaking the brick beforehand, as has been mentioned previously, is a necessity. That step might also lubricate them just a bit, and will certainly keep down both dust and heat.

Firebrick are very porous, which is part of what makes them such a good material for your hearth lining. I used an all purpose masonry tub, which allowed me to soak about a dozen brick at a time. You’ll see lots of little bubbles escaping once the brick are covered—it looks like an aquarium. You’ll also hear a hissing sound as water displaces air.

I think soaking the brick beforehand does more to help with cutting than spraying them would do because the soaking saturates the brick — which you also need for building the overhead arch, where you’ll be adding mortar.

Great thanks for the answer! you covered all i need for now

1 Like