Abstract: A method for making a thermal insulating material includes the steps of: providing a chamber, placing hollow geometric shapes in the chamber, closing the chamber, evacuating air from the chamber, feeding a slurry into an adjacent slurry chamber, pressurizing the slurry chamber and forcing the slurry in to the sphere chamber around the spheres against a fibrous material adjacent a side wall of the sphere chamber. The fibrous material allows capillary wicking of the liquid from the slurry around the spheres. Due to this pressure the spheres and slurry are semi dried into a green state. The material in its green state green is subsequently dried and fired to form the insulating material.