Trade pricing
Send your quantity and we'll confirm the best trade price.
Not sure on how much sealant you'll need? Use our calculator to find out.
When your project demands a sealant that performs across diverse conditions – handling significant movement, resisting intermittent fuel spills, and delivering durable performance across demanding environments. It seals critical expansion joints in high-traffic zones like car parks and industrial floors. It ensures flexible, durable connections for marine builds, vehicular manufacturing, and architectural panels. Get a resilient, elastic seal where performance matters most.
We engineered Megaprene 40GG to meet the need for a high-elasticity, single-component polyurethane sealant capable of performing in demanding construction and industrial environments. This sealant provides durable, elastic seals for movement and connection joints where chemical resistance, including intermittent fuel spills, and specific environmental certifications are critical. Unlike higher-modulus structural bonding polyurethanes, Megaprene 40GG is specifically formulated for low-modulus, high-movement sealing, ensuring the joint itself, not the bond, takes the stress.
Its joint movement capability of ±25% (ASTM C 719) means a 10mm joint can expand or contract by 2.5mm without failure, accommodating substantial building movement and reducing the risk of joint breakdown. A low modulus of 0.4 MPa @ 100% elongation ensures the sealant stretches easily, placing less stress on the bond line and adjacent substrates. This protects your work from adhesive failure, even under constant flex. Rated for intermittent fuel spills, this sealant provides critical durability for pavement joints, industrial floors, and infrastructure projects exposed to demanding service conditions.
Prepare surfaces thoroughly: they must be structurally sound, dry, clean, and free of contaminants. For impervious substrates, use a two-wipe process with Adheseal Xylene Solvent. For optimal adhesion in critical applications, pre-treat non-porous surfaces with Adheseal 50A Surface Prep. For porous substrates like concrete, prime with Everflex Supaprime Sealant Primer. Ensure a 2:1 width-to-depth ratio for joints. Control sealant depth and prevent three-sided adhesion with a compatible Adheseal backer rod or bond-breaker tape. Apply between 5°C and 40°C. Tool the sealant with a moistened spatula within the 60-minute skinning time to achieve a smooth, professional finish. Clean wet spills and tools with Adheseal Xylene Solvent. For skin, use Adheseal Hand Wipes.
Megaprene 40GG typically functions as the final sealing component in multi-stage construction joint systems. Its position requires careful surface preparation and often priming to establish an optimal bond. Following substrate cleaning and any necessary roughening, apply the appropriate Adheseal primer (e.g., Everflex Supaprime Sealant Primer for porous surfaces, Adheseal 50A Surface Prep for non-porous). Once the primer has flashed off, install a compatible backer rod to control joint depth and ensure two-sided adhesion. Then, apply Megaprene 40GG, tooling it off to create a smooth, continuous, and durable seal. This sequence ensures maximum performance and longevity for the joint.
Yes. Megaprene 40GG is designed for movement and expansion joints with ±25% joint movement capability. It remains permanently flexible and is suited to concrete panels, pavement joints, façade joints, and cladding systems where thermal and structural movement occur.
Yes, Megaprene 40GG is paintable with acrylic, oil, and rubber-based paints. Adhesion testing is recommended before full application because non-flexible paint systems may crack when the joint moves.
Yes, once cured it is suitable for below-waterline applications. The sealant must be fully cured before exposure to water and should not be used for aquarium installations or high-chlorine pool environments.
Megaprene 40GG adheres to common construction materials including concrete, masonry, timber, aluminium, painted surfaces, powder coat, fibreglass, and waterproof membranes. Adhesion testing is still recommended before large-scale application.
No. Megaprene 40GG is not recommended for bituminous substrates, EPDM rubber, or surfaces that may leach oils or plasticisers. These materials can cause adhesion failure and long-term sealant degradation.
| Application | Key benefit | Primary trades |
|---|---|---|
| Expansion joints in precast and tilt-up panels | Accommodates ±25% joint movement while maintaining a waterproof flexible seal | Commercial builders, precast installers |
| Window perimeter sealing | Creates durable weather-resistant joints around façade openings | Glaziers, façade contractors |
| Curtain wall sealing | Maintains long-term elasticity across moving façade connections | Façade installers, aluminium fabricators |
| Metal cladding and lap joints | Strong adhesion to common construction metals including powder coat | Cladding installers, sheet metal trades |
| Pavement joints, car parks, and driveways | Flexible polyurethane seal resists intermittent fuel and oil exposure | Civil contractors, concrete trades |
| General construction sealing and bonding | Single-component application simplifies on-site sealing and adhesive work | Builders, maintenance contractors |
| Marine and vehicular manufacturing | Permanently elastic seal absorbs vibration and material movement | Marine fabricators, transport manufacturers |
Start with a clean, dry, structurally sound surface. Remove dust, grease, curing compounds, release agents and any contamination that can compromise adhesion.
Allow concrete to cure for at least 28 days. Prime critical porous surfaces with Everflex Supaprime where required.
Use a fine abrasive pad where suitable, then clean using the two-wipe process and prepare with Adheseal 50A Surface Prep for critical applications.
Correct joint geometry is what lets the sealant move properly and stay bonded under load.
Aim for a 2:1 width-to-depth ratio where possible. Internal joints should be minimum 5mm wide and deep, and external joints minimum 12mm.
For joints deeper than 10mm, use open cell backing rod about 25% larger than the joint width. Where backer rod cannot fit, use bond breaker tape to stop three-sided adhesion.
For sealing work, cut the nozzle at a 45-degree angle to suit the bead size, load the sausage and gun the sealant by pushing it ahead of the nozzle.
Keep the nozzle in contact with both sides of the joint and maintain a steady continuous bead so the sealant is pressed firmly into place.
Fill the joint completely and avoid trapping air, as entrapped air can form bubbles in the cured sealant.
For adhesive use, cut the nozzle to form a triangular bead and compress the joined surfaces evenly.
Cut the nozzle at 90 degrees to bead width, then cut a wedge twice the bead height. Apply a steady triangular bead and compress surfaces to no less than 2mm.
Tool with a moistened spatula for a smooth finish. Clean wet excess with Xylene. If cured residue remains, soften with solvent and scrape carefully.
DANGER. Wear nitrile gloves, apron, safety glasses, and respirator protection where inhalation risk exists.
Use with adequate ventilation. Where inhalation risk exists, wear an organic vapour or particulate respirator meeting AS/NZS 1715 and AS/NZS 1716 requirements.
Correct substrate preparation improves long-term adhesion performance and reduces the risk of joint failure, bubbling, or delamination.
Surface prep: Allow concrete to cure for at least 28 days. Remove dust, loose material, curing compounds, grease, oils, and surface contamination before sealing.
Primer: Required. Use Everflex Supaprime on porous concrete, render, mortar, and brick substrates for improved adhesion performance.
Surface prep: Lightly abrade with a fine abrasive pad and clean using the two-wipe method with Adheseal 50A Surface Prep.
Primer: Optional. Priming improves adhesion performance on critical or highly stressed joints.
| Property | Value |
|---|---|
| Type Of Product | Polyurethane |
| Curing System | Moisture |
| Cure Time | 3mm per 24 hours |
| Density | Black 1.15, Others 1.16±0.02 |
| Shore A Hardness | 25 after 14 days |
| Joint Movement Capability | +/-25% |
| Tear Strength | 6.5N/mm |
| Elongation At Break | >400% |
| Modulus Elongation | 0.4 MPa @ 100% |
| Application Temperature | +5°C to +35°C |
| Service Temperature | -40°C to +80°C |
| Working Time | 25 minutes @ 23°C & 50% RH |
| Skinning Time | 60 minutes @ 23°C & 50% RH |
| VOC | <1.5g/L |
| Shelf Life | 18 months in original packaging |
| Storage | Cool dry between 10°C and 35°C |
| UV Resistance | 500h Good |
| Chemical Resistance | Excellent for water, detergent solutions, moderately diluted acids and alkalis, petrol and oil for short periods |
| Sealant Classification | ISO 11600 Type F Class 25 LM |
| AS1530.3 Test | Ignitability Index 0, Spread of Flame Index 0, Heat Evolved Index 0, Smoke Developed Index 0-1 |
| Colours | Black, Grey |
| Packaging | 600ml foil sausages |
Here are some common examples on where Adheseal Megaprene 40GG used by our customers.
