Adheseal N40 Slicone Sealant

For wet areas, metal roofing, marine joints, and general industrial sealing where movement, moisture, and mould are constant risks, Adheseal N40 Silicone Sealant provides a highly flexible, non-corrosive barrier. This neutral-cure oxime formulation adheres reliably without corroding sensitive metals like galvanised steel or Colourbond, while its added fungicide inhibits fungal and biological growth in hot, humid environments.

What it does

N40 Silicone Sealant functions by reacting with atmospheric humidity to cure into a flexible silicone rubber. Because it is a neutral-curing (oxime) system, it does not release corrosive acetic acid during the curing process, making it safe for contact with concrete and zinc-coated or galvanised metals. The cured sealant maintains a waterproof, flexible joint with an elastic recovery of over 90% (ISO 7389) and a Shore A hardness of 20, allowing it to withstand prolonged outdoor exposure, marine environments, and permanent UV contact. For safety-sensitive environments, the cured sealant is safe for use in food preparation areas and is fire tested to AS/NZS 1530.3-1999 with a Smoke Developed Index of 0-1.

Where to use it

This sealant is suitable for internal and external applications across a wide range of materials and trades:

• Substrates: Glazed and unglazed ceramic tiles, porcelain, enamel, glass, aluminium, timber, fibreglass, laminated kitchen benches, Colourbond, zincalume, and galvanised metal.
• Plumbing and Roofing: Sealing metal roof sheets, flashings, guttering, and water sealing.
• Wet Areas: Joint sealing in shower walls and floors, commercial kitchens, laundries, steam rooms, and spa rooms.
• Industrial and Fitout: Marine and boat building, vehicle fabrication, shopfitting, sign manufacture, air conditioning, sealing electrical installations, and formwork sealing.

Limitations

• No Confined Spaces: Do not use in totally confined spaces; the sealant requires atmospheric humidity to cure and will fail to set without air access.
• Not for Aquariums: Do not use as an aquarium sealant.
• No Structural Glazing: Do not use for structural glazing (use N-80 or N-60 Glazing silicone instead).
• Under Water Limits: Not suitable for underwater applications (including swimming pools) during installation, though once fully cured it is rated for below-waterline applications.
• Mirror and Panel Exclusions: Do not use for adhering mirrors (use High Power 609, subject to a test first) or composite panels (PU50FC is recommended, subject to test).
• Stone Warning: Not recommended for use on some stone without completing a stain testing program first.
• Traffic and Walkways: Not suitable for horizontal walkways or trafficable areas.
• Substrate Cautions: Do not use on polycarbonate sheeting. The sealant may discolour copper and brass.
• Non-Paintable: This silicone cannot be painted. Do not attempt to paint over the cured joint.
• Chemical Exposure: Do not clean or treat the sealant with materials, cleaning agents, or solvents that may affect or discolour it, particularly during its curing window.

Numbers that matter

• ±30% Movement Capability: Accommodates joint expansion and contraction under physical and thermal load (tested up to ±30% in physical properties; ±25% joint movement capability under service conditions).
• -50°C to 150°C Temperature Resistance: Maintains its flexible rubber seal across extreme thermal service windows.
• 2mm Per Day Cure Time: Cures at a rate of 2mm per day at 25°C and 50% relative humidity, with a skin time of approximately 20 minutes (cure times vary with atmospheric conditions and substrate porosity).
• 300% Elongation at Break (ISO 8339): High elasticity preventing adhesive or cohesive failure under tension.
• 43g/L VOC: Low-VOC formulation conforming to the Californian Bureau of Air Quality Management Rule 1168 to meet green star environmental criteria.

Installation and joint design

Apply the sealant at temperatures between 5°C and 40°C (the physical property application limit is +5°C to +35°C). All joints must be structurally sound, dry, clean, and free from surface water, dampness, oils, grease, curing compounds, or dust. New concrete must be allowed to cure for at least 28 days to prevent subsequent delamination, poor adhesion, or mould growth behind the joint.

To prevent 3-sided adhesion and ensure the sealant only fixes to two surfaces, use a polyethylene backing rod or release tape. For joints greater than 10mm deep, use a backing rod 25% larger than the joint width. N40 should be applied at a 2:1 width-to-depth ratio. Refer to the joint design parameters below:

• Internal joints: Minimum width of 5mm, minimum depth of 5mm (up to 10mm width, depth should equal the width).
• External joints: Minimum width of 10mm, with depth controlled between 5mm and 8mm.
• Maximum dimensions: Maximum joint width is 30mm; maximum joint depth is 15mm.
• Priming: While an adhesion test is always recommended, use Adheseal Primer 50A for non-porous substrates and Everflex Supaprime for porous substrates. Let the primer dry for several minutes to allow the solvent to evaporate before applying sealant.

Apply the sealant by pushing it ahead of the 45-degree angled nozzle to force the material firmly into contact with both joint faces. Tool the joint with a moistened spatula to achieve a smooth finish before the skin forms (within approximately 15 minutes). Clean off excess wet silicone immediately; cured silicone must be removed by mechanical scraping with a blade, which can be softened beforehand using white spirit solvent.