Abstract: A non-porous sheet for bonding to honeycomb-type core structures to be machined on a vacuum chuck includes a woven fiberglass fabric impregnated with a nonporous epoxy-thermoplastic resin having a low melting temperature. The epoxy-thermoplastic resin comprises a blend of bisphenol-A based epoxy and phenoxy thermoplastic. The nonporous sheet is exposed to a relatively low temperature for about five minutes to soften the epoxy-thermoplastic resin. A core structure is placed on the softened sheet and the sheet is allowed to cool to ambient temperature to adhere the non-porous sheet to the core. The core and sheet assembly can then be placed on the surface of a vacuum chuck associated with a machine tool for a subsequent machining operation of the core structure. When the machining operation is finished, the nonporous sheet is easily removed from the core structure by heating the core and sheet assembly slightly above ambient temperature and then peeling off the sheet from the core for reuse.