Abstract: A generally rectangular, double-walled box 10 is blow molded in a pair of separately formed diagonal halves 10a and 10b, each including adjoining side walls 11 and 12 subtending a diagonal half of the bottom 15 of box 10. Walls 11 and 12 of each diagonal half are oriented obliquely to the parting plane 43 of a mold 40 that has a cavity 42 and core 41 for forming the inner and outer walls of each box half 10a and 10b. The halves are assembled together along a junction region 13 and 14, preferably so as to trap a hinged cover 20. By filling the interwall cavities of the box with a suitable insulation material, the box can be used for fire resistant storage or cold storage.

Abstract: A vapor-sealed insulation system 10 for a fire resistant safe with a steel outer body 11 and door cover 12 uses several resin molds 15-17 that receive and hold the safe's insulation material and are shaped to fit within door 12 and body 11 for lining the safe's interior. The molds 15-17 not only preform the insulation but seal in its moisture. When the insulation molds are installed in the safe, their inner walls form interior safe surfaces.

Abstract: A safe has a self-sealing jamb where the door confronts and fits together with the box. This is done by forming the confronting surfaces in the jamb region of a resin material and making the jamb region non-linear in cross section and long enough in cross section so that after an outer portion of the resin material is burned off in a fire, a charred residue and a plasticized portion of the resin material remain in the jamb region to seal the door to the box around the jamb region for substantially preventing heat conduction or passage of hot gasses through the jamb region to the interior of the box. The safe can also be formed in a resin mold for the box and the door with the mold remaining in place when the safe is used. The mold is preferably filled with a non-flammable, thermal insulating material having a substantial volume of chemically bonded water and made thick enough to maintain the interior of the box below 180.degree. C for one hour in an ambient atmosphere of about 927.degree. C.