a method of manufacturing a hollow machine blade consisting of two skins ining an internal cavity and interconnected by stiffeners comprises : forging and machining the primary components of the blade , including forming a reserve of material in localized regions of the inner faces of the skins , trunnion forming elements at the ends of the components , and locating holes in the components ; deposition of diffusion barriers involving application of a mask , cutting the mask to a predetermined pattern using a special - purpose tool , peeling away portions of the mask , deposition of a coating product , peeling away the remainder of the mask , prefiring treatment , cleaning and checking ; assembly of the primary components followed by isostatic - pressure diffusion welding ; and subjecting the assembly to inflation under gas pressure and superplastic forming in a mould in order to shape the skins and form the interconnecting stiffeners , including the steps of cold - debonding the primary components , causing flow of the material reserved in the overthickness around the blade cavity , and extraction of the blade from the mould by way of mechanical means placing the blade under constraint after the forming of the blade .