Patent ID: 8584726

Claim:
A tool for use in bonding together layers of a shell by the differential pressure bonding process, the tool comprising: a plurality of separable mandrel segments that combine to form a hollow mandrel having a longitudinal axis, an outer surface, an open upper end, and at least one substantially continuous inner surface, the inner surface having a substantially axisymmetric shape having complex curvature; a retort configured to at least partially shroud the outer surface and open upper end of the hollow mandrel, the retort including at least one vacuum port; and an impermeable flexible membrane positioned over the inner surface of the hollow mandrel, the membrane and mandrel constructed to receive therebetween layers of a shell to be bonded together; wherein: the retort, the hollow mandrel and the impermeable flexible membrane are arranged such that: application of a vacuum to the vacuum port of the retort during a differential pressure bonding process forces the impermeable flexible membrane in a radially outward direction of the tool and towards the inner surface of the hollow mandrel, thereby forcing the flexible membrane against layers of a shell to be bonded together, when the layers are present between the impermeable flexible membrane and the inner surface of the hollow mandrel and wherein the flexible membrane is removed from the inner surface of the mandrel and the flexible membrane is flexible when removed from the mandrel.