A first ply and then a second ply, which is superposed on the first ply, are produced on a hoop-type first support. The hoop-type first support has a first receiving surface, to form a laminate. The first and second plies forming the laminate are transferred onto an annular second receiving surface of a core so that the laminate is wrapped on the core until each ply is closed on itself and the laminate is thus closed on itself in a ring about the central axis of the core.