The possibility of pressure slip casting of carbon free refractory suspensions with optimized grain size distributions and particle diameters in the range of millimeters is investigated. The slip flow ability is examined by conducting experiments with a newly developed falling sphere viscometer. Segregation is determined by microscopy on polished samples and computer tomography. Fundamental characteristics of cake filtration are adopted to highlight the significant influences on the pressure slip casting process. Based on the laboratory experiments the results of scale up trails are presented which were conducted with a commercial pressure slip casting machine, remodeled for suspensions containing coarse grains.