Abstract: A wet-felted mat of wood fibers is acetylated by coating the mat with a quantity of acetic anhydride ranging from 5 to 70% by volume of the mat and heating the mat at a temperature of from 150.degree. to 300.degree. F. while confining substantially all of the acetic anhydride within the mat for about 20 to 120 minutes. The acetylated mat is pressed into hardboard which may be bent into a variety of loops, spirals, helices, and other curvilinear shapes to make articles of furniture, protective packaging products and the like.

Abstract: A process of two crystallization stages for reducing radioactive contamination of phosphogypsum is disclosed. In the process anhydrite crystals are obtained through dehydration of the radiation containing phosphogypsum in strong sulfuric acid; a portion of the anhydrite crystals containing the radioactive contamination is converted to substantially radiation free gypsum by crystallizing out on a large solids concentration of radiation free gypsum seed crystals; and coarse radiation free gypsum crystals are separated from small anhydrite crystal relics containing substantially all of the radioactive contamination.

Abstract: A web stiffener for use with a channel-shaped framing member to inhibit web crippling is disclosed wherein said web stiffener comprises two opposing integral compression members each having a J-shaped cross-sectional configurational whereby said compression members are adapted for nested insertion opposingly faced, having longer flanges thereof overlapping within a channel of a framing member, and said members capable of being positioned at a random location along a framing member by rotation into position facilitated by inclined edges of said longer flanges, whereby opposite bearing edges of said compression members are adapted to contact opposite arms of a channel-shaped framing member for web stiffening thereof.

Abstract: A water-based stain having a working time of from about 1 to about 3 minutes and a tack-free drying time of from about 10 to about 15 minutes at 160.degree. F. comprises an acrylic latex, a drying oil, ester gum, a glycol, a hydrocarbonaceous solvent, and pigment.

Abstract: An apparatus for the production of mineral fiber or wool felts, blankets or batts having uniform thickness and density, comprising means for fiberizing the mineral composition, a housing defining a chamber into which the fibers are introduced, a foraminous belt upon which the fibers are deposited, a rotating brush for sweeping or throwing back excess fibers, thereby leaving a uniform layer of uncompressed fibers on the felt, and a roller for compressing the layer of fibers into a felt. The rotary brush removes the excess fibers and cooperates to provide a felt which is of uniform density and thickness.

Abstract: A flexible door or curtain support comprising an elongate member having a track for supporting the door or curtain, and apparatus for providing tension between the elongate member and a supporting wall comprising a pad or wall member for engaging the wall, a pressure plate engaging the end of the elongate member, and wedge or a cam mechanism cooperating with the pressure plate and the pad or wall member, and a mechanism for moving the wedge member to provide longitudinal tension between the elongate member and the wall.

Abstract: A building board comprises a core 31 of set cementitious material, such as gypsum, faced on at least one side by a fabric or web 33 of mineral fibres embedded in the face of the core and a continuous film 32 of the cementitious material having a higher density and lower porosity than the core extending over the outer face of the fabric. The film may have a smooth surface or a desired textured or figured surface. The preferred fabric or web 33 is a non-woven glass fibre tissue and it is preferred that a continuous film 32 of gypsum at the surface should not exceed 2 mm in thickness. The board is made by bringing the fabric or web into contact with the respective face of a layer of an aqueous slurry of gypsum plaster or other cementitious material, and vibrating the layer of slurry in contact with the fabric or web until slurry penetrates the web and the latter is completely embedded.

Abstract: A suspended ceiling system comprising a plurality of inverted-T runners. Kerfed edge ceiling tile supported by runners and concealing the bottom of the runners. At least one ceiling tile having a central portion removable therefrom by being separable along a substantially vertical fine cut made by high pressure fluid jet cutting.

Abstract: A method of manufacturing flame and abuse resistant fiber panels by treating the surface of water-laid fiber mats with an aqeuous slurry of sodium silicate and calicum carbonate and drying the mats is disclosed. The slurry is applied to the wet mat after wet pressing and before drying while the mat still contains considerable moisture content. The resulting products present a hard, abuse resistant, flame resistant and water resistant surface.

Abstract: An improvement in a partition wall construction having two spaced apart rows of wall board connected to flanged studs wherein studs are supportably engaged within opposingly spaced apart channels, a bottom channel opening upwardly with bottom portions of the studs residing therein and an upper channel opening downwardly with top portions of the studs residing therein. The improvement comprises a device for prevention of squeaking at stud and runner engagements when said partition well is subjected to racking forces. Said device comprising a plurality of clips each having in cross-section a hairpin-like configuration wherein an elongate plate portion terminates in a thickened base portion, said base portion having an angled plate portion including a first leg angling back toward the elongate plate, and then terminating in an outwardly angling second leg portion, said configuration forming a hairpin-like shape defining a slot between the elongate plate and angled plate portion.

Abstract: A pivotal door for an entrance or passageway, and particularly for shower or bathtub enclosures, comprising a plurality of frame members, a panel mounted in said frame members, a channel provided in both top and bottom frame members, and a pair of pivot members each having one end adjustably retained within one of the channels, and the other end engaged in a socket provided in the shower enclosure frame, each pivot member being arranged to be affixed at any of a plurality of positions on the channel to enable the door to be utilized with enclosures having entrances of different widths.

Abstract: A composite paper particularly adapted for use as cover sheets in the production of gypsum wallboard, the paper being sufficiently porous to permit better drainage and more rapid drying in the production of the paper, and when applied to the surfaces of a gypsum slurry for forming wallboard, permits less heat to be utilized in the wallboard conversion, thereby saving energy in the board production required for drying the board. The paper comprises in weight percent:(A) fibers in an amount of from about 65% to about 90% and having a fiber freeness of from about 350 to 550 ml. Canadian Standard Freeness,(B) a mineral filler in an amount from about 10% to about 35%,(C) a binder in an amount from about 1% to about 31/2%,(D) a flocculant in an amount of from about 2 to about 4 lb./ton, and(E) a sizing agent in an effective amount to prevent water penetration.

Abstract: Wallboard joint tape is coated with joint compound as the tape is drawn through a container of the compound and made to pass through a tabbed slot in or associated with the container. The tabs urge the coated tape away from the edge of the slot which would otherwise wipe off the coating when the tape is drawn through the slot from a position higher than the slot.

Abstract: A process for producing a healed stucco of low water demand is disclosed in which calcined gypsum is treated with an aqueous solution of a gypsum solubilizing agent, preferably in an impacting blender while grinding the calcined gypsum to increase its surface area. The product can be dried for storage or sent directly to forming gypsum board.

Abstract: A tie-down runner to increase resistance to shear and racking forces in mobile home wall constructions is disclosed. Said tie-down runner having a generally J-shape and suitable for use at upper and lower ends of wall studding to increase resistance to said forces and to additionally provide increased attachment surfaces for interior wall panel members. A method for increasing resistance to shear and racking forces is also provided.

Abstract: Air heated outside the calcining zone of a shaft kiln is passed through raw material in a hopper mounted above the kiln in order to preheat the raw material. In one embodiment the preheating air is heated by an excess air burner which communicates with the hopper. In another embodiment, the hot calcined material is cooled by forcing cool air through it and the heated air is utilized as preheating air by directing it through a by-pass conduit which connects the cooling zone of the kiln with an extension of the hopper. In neither embodiment does the preheating air constitute combustion supporting air.

Abstract: A method of surface treatment for plaster articles to improve wear and water resistance is disclosed. The method includes the step of forming the article, allowing the article to set, drying to remove excess water, applying a coat of substantially molten Candelilla wax onto an exterior surface of said article, maintaining said wax at a temperature of no less than 155.degree. F. (68.degree. C.) for sufficient period of time to allow said wax to substantially fill exterior pores and irregularities, and cooling said article to solidify the wax. Also disclosed is a wear resistant and water repellent plaster article comprising a formed plaster article having an exterior surface portion thereof coated with a thin layer of Candelilla wax, said coated surface portion providing a substantially water impregnable barrier and providing enhanced wear resistance.

Abstract: A rapid reaction of high alumina cement, gypsum, lime and water produces cementitious compositions in which the only significant factor contributing to strength during the very early stages of hydration (i.e., a few minutes to a few hours) is the formation of an amount of ettringite equal to from about 40% to about 60% of the weight the paste of water, the high alumina cement, the gypsum source, and the lime source. A substantially impermeable concrete having a 4-hour compressive strength of about 8000 p.s.i. may be produced from the cement powder of this invention.

Abstract: An apparatus for producing mineral fibers by low pressure air fiberization having a housing defining a substantially toroidal air chamber and having a substantially circular central opening, an annular slot provided around the central opening having an annular shroud affixed to the housing at the outer edge of the annular slot for confining and directing the primary jet leaving the annular slot and enabling it to be more efficiently utilized in fiberizing the mineral fibers. A cup-form spinner is mounted on a substantially horizontally oriented shaft arranged to be rotated. The spinner is mounted in front of the forward wall of the plenum and with the open end facing the forward wall. A duct is provided to direct molten slag into the spinning cup which ejects the molten slag into an air stream directed from the annular slot of the chamber and the shroud, thereby producing mineral fiber of excellent quality and in greater yield than results when the shroud is not utilized.

Abstract: An apparatus for cutting a newly formed continuous sheet being transported longitudinally along a belt conveyor, and particularly a newly formed gypsum board sheet, the cutting taking place in a direction transverse to the direction of movement of the sheet, comprising a frame, a high pressure fluid jet cutter mounted to move obliquely with respect to the direction of the moving sheet, wherein the vector component of velocity of the forward motion of the cutter equals the forward velocity of the moving sheet, and means for rotating the support on which the jet cutter is mounted to another oblique position so that a successive cut may be made from the other side. In an improved embodiment, tank means is arranged to catch the spent fluid from the jet cutter so that the cutter may traverse the moving sheet from either side successively without turning off the fluid jet.