A splice between ends of a pair of telecommunications cables is encapsulated in a thermoset foam. To encapsulate the splice it is positioned within a mold with the cables extending through apertures in the mold. At the apertures the cables are wrapped with an open cell foam material to block the cavity ends. A foam base material is then mixed with an activating agent which includes both a heat activated blowing agent and a material which reacts exothermically with the foam base material. The mixture is deposited within the mold and the mold closed. The mixture then foams to fill the mold and rapidly cures. The resulting joint is light, durable, waterproof and re-enterable.