Pasco Hypersil 912 Silicone Sealant

For wet areas, kitchens, and laundries where constant moisture and steam promote fungal growth, Pasco Hypersil 912 Silicone Sealant provides a 100% neutral-curing barrier that inhibits mould and mildew growth. It bonds without corroding metals, making it suitable for sealing stainless steel benches, sinks, basins, bath tubs, and showers.

Where to use it

Hypersil 912 provides adhesion to common building substrates and wet-area fittings, including:

• Glass, splashbacks, porcelain, and ceramic tiles
• Aluminium, steel, and stainless steel benches without risk of metal corrosion
• Concrete and grout lines
• Painted and powder coated surfaces, natural and reconstituted stone, and most plastics (test surface area for compatibility, adhesion, and staining prior to application)

Numbers that matter

• ±25% joint movement: Absorbs expansion and contraction in high-humidity zones like tiled shower corners and junctions without tearing.
• 400% elongation at break: High elasticity prevents adhesive failure under physical stress.
• 8 to 10 minutes skin time (at 20°C and 50% RH): Quick initial set requiring dry tooling immediately after application to achieve a smooth finish.
• 5 to 7 days full cure (10mm depth at 25°C): Deep section cure window before the joint reaches full physical properties.
• -42°C to +170°C operating temperature: Retains its physical properties under extreme thermal stress, from cold concrete joints to hot splashbacks.
• VOC less than 5% (50g/L): Complies with 5-Green Star rating requirements for low indoor emissions.

Limitations

To prevent premature joint failure, staining, or adhesion loss, observe the following service limits:

• Do not use for joints subjected to permanent water immersion, including aquariums.
• Do not use as a trafficable sealant or on joint paths subjected to foot traffic.
• Do not use as a structural glazing sealant.
• Do not paint; the 100% silicone surface will not accept coatings.
• Do not use on polycarbonate plastic sheeting.
• Do not apply on any substrate containing bitumen.
• Not suitable for certain rubber products where plasticiser bleeding may occur.

Joint design and backing rules

Correct joint depth must be controlled using an open-cell polyethylene backing rod compressed by 25% when inserted. Follow these width-to-depth ratios during installation:

• Joint widths from 6mm to 10mm: Joint depth must equal the joint width.
• Joint widths from 10mm to 20mm: Joint depth must be kept to a flat 10mm.
• Joint widths from 20mm to 25mm: Joint depth must be exactly half of the joint width.

Application steps

All surfaces must be clean, dry, sound, and free from dust, oil, rust, old sealant, or other contaminants.

• Clean glass and metal substrates with methylated spirits, then wipe the solvent from the surface with a clean, dry cloth before application.
• Cut the cartridge tip, then cut the nozzle to the desired bead size at a 45° angle.
• Apply the sealant using conventional caulking tools, ensuring the bead wets both sides of the joint.
• Dry tool the sealant immediately before the 8-to-10-minute skin window closes.
• Remove excess uncured sealant immediately with a cloth and solvent, such as mineral turpentine.