Method for the production of a closed edge refractory foam filter, by providing a reticulated foam substrate having at least one first surface for forming a side face of the filter and two opposed second surfaces for forming the through-flow faces of the filter, applying a liquid including an organic coating component to the first surface, solidifying the organic coating component to form a filter precursor having a continuous volatilizable coating on the first surface, and impregnating the filter precursor with a slurry containing particles of a refractory material, a binder and a liquid carrier. The impregnated filter precursor is dried and fired to form the filter having a closed edge.