sand mold for shaping molten metal cast into the mold . the mold includes sand , a thermally oxidizable polymer amongst the grains of the sand , and a catalyst coating on the gains for promoting the thermal oxidation and breakdown of the polymer in the course of removing the sand from the casting and / or reclaiming the sand for reuse . the catalyst coating adheres so tenaciously to the grains of sand that the sand can withstand repeated casting and sand reclamation cycles without the need to replenish the catalyst .