Method of producing a dam for a communication cable

A method of producing a gas-tight dam for a gas maintenance communication cable comprising the steps of exposing transmission members by stripping the sheath of the communication cable, the cable having gaps among the component transmission members within the sheath, covering exposed portions of said transmission members with a mold, and injecting a self-curing resin into said mold to cure said resin;

• characterized in that said resin is a resin to be cured while being foamed,
• first selecting a resin and catalyst mix with a cream time sufficiently long so that the resin remains fluid for a time sufficient to permit intrusion of the resin for a short distance into said gaps, and
• second selecting said resin catalyst mix with a cream time sufficiently short so that the longitudinal flow of the resin longitudinally into said gaps is arrested by the increasing fluidity resistance of said resin in said gaps as said resin cure progresses by the expansion of volume of the resin during foaming, whereby said resin is cured under a high pressure.

A method of producing a gas-tight dam for a gas maintenance communication cable comprising the steps of exposing transmission members by stripping the sheath of the communication cable, the cable having gaps among the component transmission members within the sheath, covering said exposed portions of said transmission members with a mold, and injecting a self-curing resin into said mold to cure said resin,

• characterized in that said resin is urethane which self-cures on reaction of isocyanate with a compound having reactive hydrogen and vaporizes a foaming agent of polychlorofluorocarbon with heat generated in said reaction,
• selecting the proportions of resin and catalyst mix for a cream time of at least about 20 seconds so that the resin remains fluid for a time sufficient to permit intrusion of the resin for about 20 mm into said gaps, and
• second selecting said resin and catalyst mix proportions for a cream time of a maximum of about 60 seconds so that the flow of the resin longitudinally into said gaps is arrested to a maximum of about 80 mm by the increasing fluidity resistance of said resin in said gaps as said resin cure progresses by the expansion of volume of the resin during foaming, whereby said resin is cured under a high pressure.