A method of making a vacuum fused-particle mold involves bringing the outer surface of a flexible bladder into contact with a master part; drawing a first vacuum between the flexible bladder and the master part to cause the flexible bladder to conform to its shape; placing a quantity of particles inside the compartment in sufficient quantity and distribution to cover at least a portion of the inner surface of the flexible bladder that conforms to the shape of the master part; sealing the mold compartment with a rear bladder; drawing a second vacuum on the mold compartment to hold the quantity of particles in place; removing the first vacuum to release the master part; and maintaining the second vacuum on the compartment to retain the shape of the flexible bladder. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract.