1301868 Moulding tanks OWENS-CORNING FIBERGLAS CORP 15 Oct 1970 [15 Oct 1969] 49074/70 Heading B5A [Also in Division E1] In a method of producing an underground storage tank of, for example, spherical, ellipsoidal or parabolic shape, first and second wall sections are each produced by depositing hardenable synthetic resin and randomly dispersed chopped glass strand on the convex surface of a mould and curing the resin, the congruent ends of the sections are then placed in abutment and permanently joined by spraying chopped strand and resin in a band of uniform width over the line of abutment and curing the resin. A spherical tank is made in two halves 12, 14 each formed by first applying a coating of release agent to the surface of a hemispherical mould and then spraying a coating of resin 43 by a gun 44 followed by applying a thin mat 42 of individual glass filaments bonded by a binder followed by an additional resin coating applied by a further gun. The chopped strand resin wall 47 in then built up by means of a resin gun adjacent a chopped strand gun applicator 46. Curing of the resin may be assisted by a heater 49. The joint, Fig. 3, between the abutted halves may comprise alternate layers of chopped strand mat 33 of woven roving 32, 34 in the form of narrow bands in a matrix of cured resin; alternatively it may consist of a resin matrix reinforced with a helically wound continuous glass yarn. An assembly of fittings comprising threaded conduits 62 and a handling lug 26 on a base may be secured to the tank by building up a pad on the tank wall comprising layer of resin saturated reinforcement 52, applying the assembly before the resin has cured and applying additional resin saturated reinforcement over the assembly. In a modification the tank wall is appropriately shaped to provide a flat surface for the fitting without the need for a build up pad.
