Abstract: The present disclosure relates to a system for fabricating a mold positive via additive manufacturing to form a casting mold. The mold positive material may have a first portion that undergoes a solid to gas phase transformation at a first temperature and a second portion that undergoes a solid to gas phase transformation at a second temperature. The first portion may be formed within the second portion, and the first temperature may be low relative to the second temperature. The first portion of the mold positive may thermally decompose at a lower temperature than the second portion, which may create voids within the mold positive so that during the higher temperature combustion of the second portion of the material, the second portion may expand into the newly empty spaces instead of into a ceramic casting mold. This may greatly reduce stress on the casting mold.