Abstract: A heating panel array is of a "sandwich" configuration and employs a serpentine resistive array fabricated from a metal foil and disposed between two sheets of fiber glass cloth, all of which are secured together by a binder having stable properties in the presence of heat generated when said array is energized. The binder contains colloidal silica spheres of submicron diameter. Methods for fabricating the panel are described which enable fabrication of a multiplicity of panels using selective etching and silk screening techniques. The fabrication process assures the absence of impurities in the heater panel construction and in conjunction with the binder enable the panel to operate without smoking and aromatic problems.

Abstract: A radiant heater of panel form comprises an electric resistance heater sandwiched between a non-conductive flat front panel and a thermal insulator in the form of an open-celled honeycomb panel having closed front and rear faces. An electrically non-conductive rear panel is bonded to the rear face of the honeycomb panel. The front panel is selected for maximum emission at temperatures below 200.degree.F. The interior of the rear face of the honeycomb panel is provided with a heat reflecting metallic foil layer which acts as a directional heat reflector. The over temperature protection device for the panel heater is positioned entirely within the honeycomb panel between the front and rear faces thereof.