Conductive Caulk

Conductive caulk is an electrically conductive acrylic latex sealant designed to maintain electrical continuity across every seam and penetration in a shielded room. A Faraday cage is only as effective as its joins — a 60 mm slit at 2.4 GHz lets WiFi through unattenuated. Conductive caulk closes those leaks while staying paintable, flexible and weather-resistant.

EMCaulk exceeds ASTM C-834 Type P, Grade -18°C. Each 10.1 oz tube covers approximately 54 linear feet at a 3/16" bead, fills joints up to 1/2" wide, tools in 10–15 minutes, reaches tack-free in 60 minutes, fully cures in 10 days. Paintable, soap-and-water cleanup, phthalate-free. We stock EMCaulk Classic (standard formulation for SCIF wall seams and RF-room joints) and EMCaulk Flex (higher post-cure flexibility for joints that move). Pair with YSHIELD paints and shielding fabrics for a complete envelope.