Producing a high quality, defect free shell is of the utmost importance to having success in the investment casting industry. Without understanding the behavior and interaction of the constituents of the slurry systems it becomes extremely difficult to produce a shell with the desired properties for use in the aerospace foundry. Measuring and tracking key slurry parameters such as pH and viscosity are important for understanding and maintaining consistent shell properties; such as Modulus of Rupture, Thermal Expansion, and Porosity. It is inevitable that the slurry will eventually decay causing a fluctuation in the properties of the shell. Recognizing, measuring and understanding these changes will allow for the development of process parameters that can adsorb these fluctuations and still produce a high quality casting.