Abstract: A collapsible, cantilevered mandrel is disclosed comprising a core rotatable about a longitudinal axis, a tubular shell having a longitudinal slit to permit collapsing of the shell, means for rigidly mounting an arcuate segment of the shell to the core such that the shell is disposed about the longitudinal axis, and means for collapsing the mandrel. The means for collapsing the mandrel includes an actuating member mounted between the core and the shell for reciprocal motion, and a plurality of linkage means connected to the actuating member. Each linkage means is connected to first and second portions of the shell on opposite sides of the slit, and is adapted to cause at least one of the first and second portions to move circumferentially towards the other portion and radially inward when the actuating member moves.

Abstract: Spray gun (10) includes a unitary valve (22) for controlling the flow of polyester resin and catalyst through the gun and discharging the polyester resin and catalyst in converging streams from nozzles (24) and (26) so that the two liquids thoroughly mix as they flow together through the air. Valve (22) includes a rearward, catalyst mixing section (82) composed of an inlet sleeve (90) and an outlet sleeve (91), and a forward resin flow control section (84) composed of an elongate inlet sleeve (144) and an end sleeve (150). Inlet ports are formed in sleeves (90) and (144) and outlet ports are formed in sleeves (91) and (150) to permit the flow of catalyst and resin when an elongated needle (80), extending longitudinally through the center of the sleeves, is disposed in rearward, activated position and to prevent the flow of catalyst and resin when the needle (80) is disposed in forward, deactivated position.

Abstract: A method for producing low density polyester foam includes heating the resin to a temperature in the range of from 80.degree. to 140.degree. F., combining the resin with a blowing agent such as a sulfonyl hydrazide, combining the resulting admixture with a catalyst, and depositing the catalyzed resin on a surface. The density of the resulting foam can be decreased by incorporating a flourinated hydrocarbon into the resin.