Uniaxial viscosity and sintering stress of pressure filtrated alumina compacts were evaluated from sinter-forging measurements. At a particular density, significantly higher values of sintering stresses are observed compared with specimens made by uniaxial dry pressing followed by cold isostatic pressing. In addition, the uniaxial viscosity at a given density is lower for the pressure-filtrated samples. These differences may be explained by a more homogeneous microstructure and finer pore size and emphasize the importance of green density and packing on the evolution of the constitutive parameters for crystalline materials.