Abstract: A sealant applicator comprising an enclosure body which is openable to receive structure defining a junction locus into its interior space. Means are provided for introducing a flowable sealant into the interior space of the enclosure, e.g., a fill tube open at one end and joined at its opposite end in closed-flow communication with the enclosure body, to deposit sealant material at the junction locus. A sealant application apparatus is also disclosed, comprising a sealant applicator of the aforementioned type, secured to the nozzle of a pressurized container containing the sealant material. The sealant applicator of the invention is particularly useful for applying electromagnetic interference- and RF leakage-blockingly effective sealant materials to cable junctions, e.g., a junction formed by a coaxial cable and a cable television junction box.