This castable refractory cement is used to repair damaged firebricks or fire-backs. The 12 1/2 pound bucket is a perfect size for homeowners and installers alike. If you need a special shape or size brick, you can use a mold to achieve the desired shape. After 24 hours, the cement will be cured and will become hard as a brick and will be able to withstand temperatures up to 2200 degrees Fahrenheit. You can use this cement for outdoor applications like fire pits or ovens as well, and if you don't like the color you can paint it when it's cured. This firebrick refractory cement is an essential addition to any home, garage, or camp. Please note that this is okay for outdoor use as the cement is not water-soluble. This product is available in two different sizes.