Dow 999A RTV (formerly Dow Corning 999A RTV) silicone building and glazing sealant is a one part acetic cure silicone sealer that cures in the presence of atmospheric moisture to produce a durable yet flexible wet glazing and curtainwall seal. This silicone caulk is formulated for conventional glazing of glass and plastic, curtainwall sealing, solar panels, and replacement glazing. Dow 999A RTV silicone sealant is intended for building construction applications, and is especially effective for glazing butt and lap shear joints, sealing curtainwall projections, glass, plastic, and metal assemblies. It is also appropriate for general use construction applications. Please note that Dow 999A building and glazing silicone caulk is not intended for structural glazing or for use on masonry. Check caulk cartridge label for additional limitations.
Butt and lap shear joints
Structural silicone glazing or joints where physical abuse or abrasion is likely to be encountered
Prolonged water immersion or adhesion to porous surfaces like masonry
Building materials that could bleed oils, plasticizers or solvents including materials such as impregnated wood, oil-based caulks, green or partially vulcanized rubber gaskets or tapes
Totally confined spaces because the sealant requires atmospheric moisture for cure
Surfaces sensitive to corrosion by acetic acid vapors (a byproduct of sealant cure)
Surfaces that will be painted since paint will not stretch with the extensions of the sealant and may crack and peel. Need to complete all painting prior to using sealant
Bonding to secondary seal of insulating glass units sealed with two-part silicone sealants
Auto trim or appliance trim (i.e., adhesive trim).
This product is neither tested nor represented as suitable for medical or pharmaceutical uses.
Dow 999A clear silicone building glazing RTV silicone sealant meets the qualifications of:
Federal Specification TT-S-001543,Class A
Federal Specification TT-S-00230,Class A
FDA Regulation No. 21 CFR 177.2600 (subject to end use compliance with any applicable total extractives limitations) – some soap residue, frost, surface dirt and old sealants or glazing compounds and protective coatings.