Abstract: A door frame having excellent fire-resistance, flexural strength and screw holding properties is fabricated from gypsum fiberboard, specifically a gypsum fiberboard having a density of at least 60 lbs./cu.ft., a flexural strength of at least about 30 lbs. (1/2" thick material), and a screw holding capability of at least about 400 lbs. A preferred gypsum fiberboard material for fabrication of the door frame comprises a composition containing a substantially uniform dispersion of solids including by weight about 65% to 90% set gypsum, about 7% to about 30% pulped paper, up to about 9% binder, and about 0.8% to 2% inorganic fiber. A wood veneer is preferably applied to the visible faces of the gypsum fiberboard door frame members.

Abstract: Glass mat-faced gypsum boards having a set core containing gypsum dihydrate and at least a minimum amount of chopped fibers, as well as other optional fire-resistant additives, are provided. The resulting boards obtain superior fire resistance properties over conventional paper-faced boards of like thickness which include a similar amount of chopped glass fibers.

Abstract: A fire-resistant door comprises a core panel of mineral material, such as gypsum wallboard. A fiber mat, preferably comprising glass fibers, is at least partially embedded in each face of said core panel. An edge banding assembly disposed around the periphery of the core panel is centrally grooved to receive the panel edges. Facing sheets are affixed to the opposite sides of the edge banding assembly in spaced parallel relation to the core panel, and a spacer material at least partially fills the spaces between the facing sheets and the core panel.

Abstract: A fire-resistant article, for example, a fire door core comprising a major amount of expanded perlite in compressed form, an adhesive material, the major portion of which is starch, and preferably glass fibers, and a method for making the article by dry-mixing the ingredients substantially completely before water is added for the purpose of developing the adhesive characteristics of the starch.