Dowsil 795 Silicone Sealant

For high-load structural glazing, panel stiffeners, and architectural joint sealing, 795 Silicone Sealant provides the physical strength to support glass and other heavy cladding materials under wind load, alongside the elasticity required for demanding weather seals. This neutral-cure RTV silicone forms a medium-modulus rubber that bonds without priming to glass, anodised or alodined aluminium, steel, painted metal, concrete, and granite.

High-movement structural and weather sealing

795 Silicone Sealant functions as both a structural adhesive and a flexible weather barrier. When applied to clean substrates, it cures upon exposure to atmospheric moisture to accommodate high-movement expansion joints. The chemical mechanism is a non-corrosive, low-odour neutral cure that will not damage sensitive coatings or Kynar paints. It maintains its mechanical bond across extreme service temperatures from -40°C to 149°C, resisting UV degradation, rain, and snow without hardening or cracking.

Numbers that matter

• ±50% joint movement (ASTM C 719): Absorbs significant thermal expansion and contraction in glazed assemblies and heavy panel systems without adhesive or cohesive failure.
• 0.414 MPa tension adhesion (ASTM C 1135 at 50% extension): Delivers the structural tensile strength required to secure glass and panel systems safely under high wind loads.
• Zero staining (ASTM C 1248): Formulated to prevent plasticizer migration and staining on sensitive porous substrates including granite, marble, limestone, brick, and concrete.
• 20 to 30 minutes working time: Provides an adequate tooling window to wet out joint faces and achieve clean, professional profiles before skinning begins (typically within 15 minutes).
• 14 to 21 days to full adhesion: Reaches full design bond strength under standard conditions (25°C and 50% relative humidity); joint mock-ups should verify adhesion before structural loads are applied.

Where to use it

This sealant is formulated for new construction and remedial installations on the following systems and substrates:

• Structural and nonstructural glazing systems.
• Structural attachment of architectural panel systems and panel stiffeners.
• Weather sealing of joints in glass, anodised or alodined aluminium, steel, painted metal, EIFS, granite, stone, brick, concrete, and many plastics.

Installation and tooling

Clean all joints thoroughly to remove grease, oil, dust, water, frost, old sealants, or protective coatings. Install backing rod, joint filler, setting blocks, and spacer shims as specified. Mask adjacent surfaces to ensure clean lines. Apply the sealant in a continuous operation under positive pressure. Tool the bead with light pressure before a skin forms (within 15 minutes) to force the sealant against the backing material and joint faces, then immediately remove the masking tape.

Limitations

795 Silicone Sealant must not be used:

• In structural applications without prior review and written approval by your local Dow sales application engineer.
• In below-grade applications.
• When substrate surface temperatures exceed 50°C during installation.
• On surfaces subject to continuous water immersion.
• On materials that bleed oils, plasticizers, or solvents, which can degrade the silicone bond.
• On wet or frost-laden surfaces.
• In totally confined joints where the sealant cannot access atmospheric moisture to cure.
• Where the sealant is intended to be painted, as paint films will not adhere to cured silicone.
• In direct contact with food, or in medical or pharmaceutical applications.