Ring compression test has been used extensively in determining the magnitude of friction coefficient encountered in large deformation processes. A common practice is to measure the percentage change in height and internal diameter of a ring specimen deformed between two flat platens. These measured values are then plotted in a friction calibration chart to determine the coefficient of friction. The main purpose of this research was to investigate whether the friction calibration curves available in the literature are valid for all material; i.e. are they independent of material properties? Utilizing the physical Modeling Technique and the Finite Element Method, a series of ring compression tests were conducted to determine the coefficient of friction, μ, and the corresponding calibration curves for two types of modeling materials with different material properties. Contrary to the results available in the literature, where the same calibration curve is recommended for all types of materials and test conditions, the results of this investigation showed that friction calibration curves are affected by material properties and that inaccurate estimates of friction coefficient can be made if the same friction calibration chart is used for all types of materials.