DOWSIL™ 121 Structural Glazing Sealant is a high-performance, two-part RTV silicone sealant engineered for structural glazing and weatherseal applications in both field and factory environments. Designed with a convenient 1:1 mix ratio and fast-curing formulation, this structural silicone provides durable adhesion and reliable performance without the need for complex two-part pumping equipment.

This neutral-cure silicone sealant is specifically developed for structural bonding of glass and façade components, offering excellent flexibility, weather resistance, and long-term durability. Once cured, it forms a medium-modulus silicone rubber capable of withstanding UV exposure, ozone, humidity, temperature extremes, and building movement while maintaining structural integrity.

DOWSIL™ 121 achieves structural strength and adhesion within 24–48 hours, significantly reducing cure time compared to many traditional one-part structural glazing sealants. Its fast cure performance helps improve production efficiency, reduce project timelines, and minimize downtime during installation or façade repair applications.

The sealant delivers primerless adhesion to glass, anodized aluminum, and alodine aluminum surfaces, while also adhering to existing DOWSIL™ structural sealants for reglazing applications. Its stable viscosity and non-corrosive cure system support clean, consistent application in deep or narrow joints without heating requirements.

Common applications include:

• Structural glazing systems
• Curtainwall fabrication and installation
• Storefront systems
• On-site glazing repair and replacement
• Attachment of panel stiffeners
• Factory and field glazing applications
• Structural and weatherseal joints in commercial façades