Thermo- and photo-initiated polymerization of emulsion templates for making macroporous poly(methyl methacrylate) materials both suffer from low energy efficiency and require tedious sample preparation (removal of inhibitors, inert atmosphere) or specialized equipment to be used. Here, an easy and efficient method for the preparation of such open pore materials with up to 93% porosity is demonstrated by using redox-initiated polymerization in the oil phase of high internal phase emulsion templates. The method eliminates the need of heating/irradiation and monomer purification, thus reducing the preparation costs without sacrificing the mechanical properties of the porous materials. It also allows of two component HIPE curing systems to be made, stored and used in the field for a rapid preparation of open pore monoliths in spaces with complex geometry. This is demonstrated by the in situ preparation of a filter and a static mixer for foam generation. The proposed method has a considerable potential for further practical exploitation in filtration, separation, microfluidics, chromatography and other fields where porous materials are used.