Within the research, selected multilayer technological systems created as combinations of water-glass containing moulding sand with
foundry tooling, were characterised on the grounds of their electrical properties. By measuring resonance frequency and quality factor of a
waveguide resonance cavity, real component of permittivity εr′ and loss tangent tgδ were determined for multilayer foundry systems with
various qualitative and quantitative compositions. It was demonstrated that combination of a sandmix and foundry tooling with known
dielectric properties results in a system with different physico-chemical properties, whose relation to the parameters of individual
components of the system is undefined at this research stage. On the grounds of measurement results, theoretical value of microwave
heating power, dissipated in unit volume of the selected multilayer foundry system, was determined. Knowledge of theoretical heating
power and evaluation of physical, chemical and structural changes occurring in moulding sands exposed to microwaves in such a
technological system makes a ground for empirical modelling of the process of microwave heating of foundry moulds and cores.