K26 bricks – capable of temperatures up to 2600F (1427C) Individual soft insulating firebrick dimensions: 9″ x 4.5″ x 2.5″ sold as a case of 25 bricks. Soft insulating fire bricks (IFB) are used for general kiln construction because they are lightweight and easy to cut without the use of special saws or tools. Also used as a heat-resistant surface for metal soldering and to fire PMC+, PMC3.