During Supersolidus Liquid Phase Sintering the viscosity of beams affects the deflection level, thus in sintering practice also the tendency to distortion. Although the deflection value increases with decreasing viscosity, a concentration gradient from surface to centre of samples may neutralise the effect of viscosity. In this paper, the deflection behaviour of Cu-28Zn beams, manufactured from prealloyed powder, at various temperatures and times ranging from 910 to 950°C and 0–90 min, respectively, was studied. The midpoint deflection was measured by the in situ bending images. To better understand the deflection behaviour, experimental results were mathematically modelled using general deflection equations. To obtain further information, microstructural studies were performed using optical and scanning electron microscopy. It is concluded that zinc evaporation influences the chemical composition and generates a thin solid layer around the sample resulting in a parabolic deflection behaviour with temperature and non-linear with time.