Aztex Inc. (Waltham, Mass., U.S.A.) has developed foam-based X-Cor and K-Cor, lightweight structural core materials that, the company says, provide mechanical strength equivalent to aluminum, Nomex or Korex honeycomb, but with lower core weights and no edge-filling necessary. The material combines a three-dimensional truss network of pultruded carbon-fiber/epoxy Z-Fiber rods in a foam medium (usually Rohacell 31IG). X-Cor truss pins (0.28-mm to 0.5-mm/0.011- to 0.020-inch diameter) protrude from the foam, and are embedded in the facesheets during sandwich panel manufacture. X-Cor is targeted to cocured structures with gentle contours and/or thick (>12.7-mm/0.050-inch) facesheets. K-Cor uses truss pins of 0.50 mm/0.020-inch diameter or greater, with pins set flush to the foam surface; facesheets are either cocured or secondarily bonded to the core. K-Cor is suitable for complex contours. Both reportedly provide excellent hot/wet properties, eliminating the corrosion and moisture-related difficulties associated with honeycomb.