A method is a described for constructing a hearing aid shell that comprises a combination of hard and soft materials. In one embodiment, 3D printing is combined with conventional mold/casting methods so that a first shell portion made of a hard material and a mold for a second shell portion are 3D printed. The mold is then filled with a soft material which is allowed to set to form the second shell portion, and the first and second shell portions are adhesively attached.