Abstract: A method of prescoring foam board for making composite panels includes impressing a pattern of ridges projecting from a surface of a die into at least one face surface of the foam board. The pattern of ridges on the die forms a pattern of indentations having three series of parallel linear indentations, each series being angularly offset from each series other by 60°. The ridges on the embossing die are pressed into the foam sufficiently deep that the the pattern of indentations impressed in the board surface after whatever springback occurs remain deep enough to enable volatiles generated in an interior zone of a panel to escape when drawn out by a vacuum pump when the foam board is heated under pressure between two face sheets of resin-preimpregnated fabric to form a composite panel.

Abstract: A foam board, for fabrication of sandwich panels made of a face sheets bonded over each side of the foam board, has two opposed planar faces having an embossed pattern in the faces. The embossed pattern has three series of parallel linear indentations, each of the series intersecting the other two series at an angle of 60°, such as a series of interlinked equilateral triangles angularly offset from the other two series. The indentations into the surface of the foam boards are sufficiently deep and close together to provide escape paths for volatiles generated during the bonding. In this way, the face sheets may be bonded over the foam board and the escape paths vent the volatiles and prevents the development of excessive pressure between the face sheets that otherwise would interfere with the bonding.

Abstract: A method of prescoring foam board for making composite panels includes impressing a pattern of ridges projecting from a surface of a die into at least one face surface of the foam board. The pattern of ridges on the die forms a pattern of indentations having three series of parallel linear indentations, each series being angularly offset from each series other by 60.degree.. The ridges on the embossing die are pressed into the foam sufficiently deep that the the pattern of indentations impressed in the board surface after whatever springback occurs remain deep enough to enable volatiles generated in an interior zone of a panel to escape when drawn out by a vacuum pump when the foam board is heated under pressure between two face sheets of resin-preimpregnated fabric to form a composite panel.

Abstract: A planar composite panel is constructed from two resin-impregnated fiber face sheet covering and bonded to the two sides of a honeycomb core element and a surrounding border element made of rigid foam board. The two planar faces of the rigid foam board are embossed with a pattern of indentations in the form of interlinked equilateral triangles which are sufficiently deep and close together to provide escape paths for volatiles generated inside the panel during curing of the resin in the face sheets by which the face sheets are bonded to the honeycomb core element and the foam board, to prevent the development of excessive pressure between the face sheets that otherwise would interfere with the bonding.

Abstract: A planar composite panel is constructed from two resin-impregnated fiber face sheet covering and bonded to the two sides of a honeycomb core element and a surrounding border element made of rigid foam board. The two planar faces of the rigid foam board are embossed with a pattern of indentations in the form of interlinked equilateral triangles which are sufficiently deep and close together to provide escape paths for volatiles generated inside the panel during curing of the resin in the face sheets by which the face sheets are bonded to the honeycomb core element and the foam board, to prevent the development of excessive pressure between the face sheets that otherwise would interfere with the bonding.