The variables of the tape casting process were optimised to produce green tapes made out of thermoelectric material powders, with sufficient strength to be handled during the post-processing stage. Most of the mechanisms and analysis concerning the organic additions to the powder, to create a flexible green tape, have been explored. The types of organic additives used in the formulation of the slurry, the effect of the ratio of the organic additives on the final physical characteristics of the green tapes are given. The manufacture of tapes characterised by the powder size, slurry viscosity, apparent and bulk densities, tensile strength, and adhesion properties is outlined. All these parameters were optimised for the specific task of fabricating a thermoelectric generator, as a monolithic block, made out of multi-layers of different materials.