Pasco Hypersil 911 Silicone Sealant

Pasco Hypersil 911 is a high-performance, 100% neutral-cure silicone for general glazing, window and door perimeter sealing, curtain walls, building cladding and exterior weatherproofing. It cures to form a tough, flexible waterproof seal with ±25% movement capability and strong resistance to UV and weather exposure.

Hypersil 911 is particularly useful where glazing and façade work needs a neutral-cure silicone that will not corrode common metals and where an architectural colour match matters. Its broad colour range makes it well suited to window frames, cladding and visible perimeter joints where the sealant finish becomes part of the façade appearance.

Neutral-cure glazing silicone for windows, cladding and curtain walls

Use Hypersil 911 for general-purpose glazing, window and door frame perimeters, curtain walls, construction joints and building claddings. It adheres to common glazing and construction substrates while remaining flexible enough to absorb normal building and thermal movement.

Why choose Hypersil 911?

• Neutral cure: non-corrosive to common metals and suited to glazing and façade work.
• ±25% movement capability: accommodates movement in correctly designed joints.
• 400% elongation: provides high flexibility before rupture.
• Excellent weathering and UV stability: suitable for long-term exterior exposure.
• Non-slump: suitable for vertical window, façade and cladding joints.
• Fast skinning: approximately 8 to 10 minutes at 20°C and 50% relative humidity.
• Service temperature: -62°C to +170°C after cure.
• Architectural colour options: useful where the weatherseal needs to coordinate with window frames, cladding or façade finishes.

Compatible substrates

Hypersil 911 provides adhesion to common glazing and building materials including glass, aluminium, steel, stainless steel, concrete and ceramic tiles. Painted and powder-coated surfaces, natural or reconstituted stone and plastics should be compatibility tested before use.

Joint design and application

All surfaces must be clean, dry and sound, with dust, oil, rust, old sealant and other contamination removed before application. Glass and metal should be cleaned with a suitable solvent and wiped dry with a clean cloth.

Correct joint geometry is important. For joints 6 mm to 10 mm wide, depth should generally equal joint width. For 10 mm to 20 mm joints, use approximately 10 mm depth. For 20 mm to 25 mm joints, depth should be approximately half the joint width. Use suitable backing material to control depth and maintain two-sided adhesion.

Apply the silicone so it fully wets both joint faces, then tool immediately to a smooth finish before the surface skins.

Where Hypersil 911 fits in the weatherseal range

Choose Hypersil 911 when you want a neutral-cure architectural silicone for general glazing, cladding and perimeter weathersealing, particularly where colour selection is important.

For higher-movement façade and curtain wall weathersealing, compare DOWSIL 791 or Adheseal N70, both of which offer ±50% movement capability.

Important limitations

• Do not use as a structural glazing sealant.
• Do not paint cured Hypersil 911.
• Do not use on polycarbonate plastic sheeting.
• Do not use on rubber products where plasticiser migration may cause bleeding.
• Do not use for aquariums.
• Do not use in joints subject to permanent water immersion.
• Do not use on bituminous substrates.
• Do not use as a trafficable sealant in walkways or pavements.

Browse the wider Window, Shopfront & Perimeter Weatherseal range for other glazing and façade joint options.