CleanBurn Castable Refractory Cement is a dry-mix cement that dries as hard as fire brick. Perfect for casting into custom designs, as it will hold its shape while drying; building firepits, and much more! Durable to be only material when casting a solid stove bed or outdoor oven. Durable, and strong - it also works to fill large holes or cracks in masonry. Effectively replace mortar and use it for for tuck-pointing. May require layering for thicker applications.