Abstract: A method and apparatus for making an insert for selectively, locally, densifying panels having a honeycomb core and at least one face sheet. At least two narrow, long foil strips are fed from supply rollers through a corrugating device which corrugates at least one of the strips. Preferably, the depth of corrugations vary greatly between adjacent strips. From the corrugating device the strips go to a take up reel which winds the strips into a flat pancake coil. When the desired coil diameter is reached the coil is secured to prevent unwinding and the coil is removed from the reel. The coils are used to replace portions of the honeycomb core to locally improve density, strength and thermal transfer characteristics of the panel.

Abstract: A ring insert for locally reinforcing a panel having a honeycomb core and at least one face sheet. The ring insert has at least two adjacent corrugated foil strips wound with the surface of the strips (and the corrugations) lying substantially perpendicular to the ring axis. The corrugations in adjacent strips have substantially different corrugation curve periods to prevent nesting of the corrugations of one strip into those of the next strip. The strips are bonded together to form a unitary ring. These inserts are adapted to be placed in cut-outs of corresponding shape in a honeycomb core and to be bonded thereto and to the panel face sheets. A method and an apparatus for winding the coil are also disclosed.

Abstract: Apparatus and method for welding high electrically conductive metal and metal alloys. High thermal and high electrical conductive metals such as, for example copper foil and the like, normally unweldable by resistance welding means due to their physical makeup, can now be welded in a conventional manner by the use of pairs of welding electrodes constructed of molybdenum.