The application of 3D printing techniques is a recently developing area used within foundry technology. Digital production of sand molds and cores eliminates the need for hard tooling, drastically reduces lead times and offers design freedoms not possible in the traditional pattern making. Even though mold and core making technologies are refined from both scientific and practical points of view, casting defects may still occur in the final products. Thus, molding material related casting research is required to generate state-of-the-art methods and understandings to avoid the formation of casting defects. In this paper, a pioneering method is presented which is suitable to determine novel thermophysical and heat transfer properties of various types of molding materials. These properties are strongly connected to the cooling capacity and the gas evolution features of the cores used in casting production. The method is based on temperature measurements inside spherical shaped core sand specimens and evaluated by a special application of Fourier thermal analysis. Temperature measurements were performed in test samples produced by two different 3D core printing systems. The registered temperature data were processed by Fourier thermal analysis to calculate the thermal properties and the decomposition characteristics of the 3D printed cores. The experiments were executed under different heating conditions analogous to aluminium and cast iron production.