CRL Dow Corning® 999-A Black Silicone Sealant for Glazing & Building

• General purpose silicone glazing sealant for windows, curtainwall, and solar panels
• Easily applied one‑part, high‑modulus acetic‑cure formula
• Sealant Estimator Chart

CRL Dow Corning 999-A (SKU: 999ABL) is a one‑part acetic cure silicone sealant that cures with atmospheric moisture to form a durable, flexible weatherproof seal. Ideal for wet glazing and curtainwall joints, it’s designed for conventional glazing of glass and plastics, curtainwall sealing, solar panel seals, and replacement glazing.


Basic uses
Dow Corning 999‑A is formulated for building construction glazing: glazing butt and lap shear joints, sealing curtainwall projections, and joining glass, plastic, and metal assemblies. It is also suitable for general construction sealing where a flexible, weather‑resistant silicone is required.

Technical data
Meets or exceeds: Federal Specs TT‑S‑001543A (COM‑NBS) Class A, TT‑S‑00230C (COM‑NBS) Class A; ASTM C‑920; Canadian CAN2‑19.13‑M82—making it compliant with common building and silicone sealant standards.

Limitations
Not intended for structural glazing or use on masonry. Review cartridge label and the Specification Data Sheet for additional application and substrate limitations.

Comparable sealants
CRL: 33S. Dap: 100% Silicone. Dow Corning®: 786; 732; 700; Glazing Silicone; General Purpose; Commercial Grade 100%; Tub, Tile and Ceramic, HVAC/R. GE®: 1200 Construction, 1000 Contractors, 1700 Sanitary. Tremco®: Proglaze, Tremsil 200, TremPro 644. OSI: HM‑270. Pecora: 860, 863. Sonneborn: OmniPlus. Sika®: SikaSil®‑GP.


Product Warning:

Dow Corning 999‑A Silicone Building and Glazing Sealant is not intended for structural glazing or for use on masonry. Check cartridge label and Specification Data Sheet for additional limitations.