In this work commercial polyurethane sponges with open porosity of approximately 13 pores per inch were chosen as the templates to produce the SiC RPCs. Effects of the theological behavior of the slurry on the coating quality and the properties of SiC RPCs such as strength, density, microstructure, were investigated in detail. The coating quality was found to depend strongly on the slurry viscosity and this was improved dramatically extremely as the viscosity increased. The SiC RPCs displayed a remarkable increase in the flexural strength as the solids content increased. In addition, the increase of the polymer content had also a little contribution to the improvement of the strength The optimum solids content and polymer content were found to be 80 and 0.20 wt.%. This study shows that the control of slurry theology is very important for the processing of RPCs.