reducing the number of pieces with cracks the first step in the process of the present invention involves preparing a monolith comprising a polyolefin a ceramic powder and a plasticizer each of these components is essential for the attainment of desirable performance characteristics in the end product as shown in f j sergeys u s pat no re 28 195 the preparation of said porous ceramic monolith comprises the following steps a a polyolefin is blended with a ceramic filler and plasticizer b the composite is heated to thermoplastically compound the mixture and shaped into a structure containing a plurality of channels d at this point the porous ceramic structure is ready to be fired to accomplish the polyolefin removal and ceramic sintering according to the present invention it has been discovered that the firing process can be carried out either at controlled reducing atmosphere conditions or preferably in view of reduced fuel consumption at normal stoichiometric flame conditions followed by subsequent sintering in either case without the occurrence of cracking in any portion of said structures provided said structures have been immersed prior to firing into a 1 2 aqueous solution of a surfactant the surfactant is added to cause wetting of the solvent extracted structure consisting of the ceramic powder polyethylene and.