Fortunately, the firebricks are softer and more porous. They can be cut easily with an electric blade used for wood cutting. There are various ways to cut the firebrick. But it all depends on the thickness. For normal to high viscosity, you can place the brick at the deck of the electric blade. Clean the deck and measure the angles correctly. Start the blade and slowly cut the firebrick; stop the blade first, and then lift it to save the brick from unnecessary cuts.