Spraying and coating of materials involves a complex interplay of fluids, substrates and the environment. Only by understanding heat transfer, wetting and fundamental rheology can a reliable insight into the critical processes involved be determined. Rates of deposition are important, through the interplay with the viscosity, but the exact nature of the rheological response is also important, whether the fluid is shear thinning, or extensionally hardening, or posseses a yield stress. Cambridge Polymer Group is one of a few labs in the world that understands both shear and extensional rheology, the interplay of which is critical in free surface coating and spraying applications.