Method of making valve seats by thermally spraying bulk material. The method includes the steps of: (i) preparing a cylindrical polymeric mandrel having an outside dimension not greater than the desired inside dimension of the desired insert, the mandrel having no means to provide for separation of the sprayed material from the mandrel, (ii) thermal spraying separate particles of one or more types of steel or nickel alloys in the presence of a controlled oxidizing medium under conditions that allow firstly, melting of the mandrel and its infiltration into the sprayed material and secondly to form a subsequent polymer free dense metallic bulk composite material (iii) after cooling, machining and cutting into discrete seat shapes for implanting into the final product.