The ferrules and feeding head and supply elements, insulating or exothermic, are obtained by blowing or manual molding from a formulation which comprises aluminium silicate hollow micro beads, with an alumina content below 38% in weight, an agglomerant and optional loads, in non fibrous form. Depending on the density of the micro beads, appropriate formulations may be obtained for the manufacture of ferrules and insulating and exothermic feeding head and supply elements. the ferrules obtained, have an external and internal dimensional exactness and may be coupled to the mold after production, without additional handklings and in a manual or automatic manner. Said ferrules are of interest in the production of metallic ferreous or non ferreous parts.