At a Glance: Key Applications
Use Megapoxy 69 for: Structural bonding of timber, steel to concrete, stone fabrication, and critical repairs on vertical or overhead surfaces where high-strength and impact resistance are essential.
Megapoxy 69: A Technical Overview
Megapoxy 69 is a professional-grade, two-component structural epoxy adhesive with a non-sag gel consistency. It is engineered to provide extreme bond strength and durability for the most demanding civil engineering, commercial, and marine applications. Its unique formulation provides a versatile adhesive that will not slump on vertical or overhead surfaces, making it the definitive choice for complex repairs and fabrications. As demonstrated in the structural repair of the heritage-listed Crankies Plain Bridge, Megapoxy 69 is proven to withstand high impact forces and deliver the long-term performance required for critical infrastructure assets.
Comparative Performance Overview
| Metric | Megapoxy 69 | Mechanical Fasteners (Bolts/Screws) | Advantage |
|---|---|---|---|
| Load Distribution | Continuous bond across entire surface | Concentrated at point loads | Distributes stress evenly across the bond line, reducing stress concentrations and increasing the overall strength and fatigue resistance of the assembly. |
| Sealing & Protection | Creates a permanent, waterproof seal | Creates penetration points for moisture | The continuous epoxy bond acts as a complete barrier to water and chemical ingress, protecting substrates like timber and steel from rot and corrosion. |
| Vibration Resistance | High impact resistance; monolithic bond | Can loosen under vibration | Forms a solid, unified assembly that dampens vibration and resists loosening, critical for high-traffic structures like bridges or dynamic machinery mounting. |
| Aesthetics | Invisible bond line | Visible heads and hardware | Allows for clean, seamless finishes in architectural applications like stone fabrication and structural timber joinery where appearance is critical. |
Using Megapoxy 69 in a Complete System
Megapoxy 69 is a vital component within a multi-stage repair and fabrication system. Its primary role is to act as the primary structural adhesive and void filler for larger, non-slump applications. As shown in the Crankies Plain Bridge case study, it was used to seal large holes and splits in the timber chord. This application creates a fully contained, structurally sound void that can then be injected with a lower-viscosity epoxy like Megapoxy 108. This system-based approach ensures a comprehensive repair where every component—from the substrate to the final finish—is chemically and mechanically integrated, resulting in a monolithic and incredibly durable final structure.
How Megapoxy 69 Prevents Common Failures
Common failure prevention information
Failure Mode: Adhesive Slump on Vertical Surfaces
With its non-sag gel consistency, Megapoxy 69 holds its form when applied to vertical or overhead surfaces. This prevents the adhesive from running or dripping out of the joint, ensuring the correct bond line thickness and full surface contact are maintained throughout the cure for maximum strength.
Failure Mode: Bond Failure Under Impact or Dynamic Load
Engineered to retain its high strength after repeated high-impact forces, Megapoxy 69 is ideal for dynamic applications. Its formidable bond (e.g., 30 MPa to steel) and high compressive strength (70 MPa) ensure the connection remains intact on structures like high-traffic bridges or heavily used joinery.
Failure Mode: Cold Joint Weakness in Composite Bonds
Megapoxy 69 creates a continuous, high-strength chemical bond that seamlessly transfers load between different materials like steel and concrete. This eliminates the concentrated stress points and inherent weakness of a simple mechanical 'cold' joint, producing a truly integrated structural element.
Core Features & Specifications
- Non-Sag Gel Consistency: Ideal for vertical and overhead applications, it stays in place without slumping, ensuring perfect joint filling and contact.
- High Compressive Strength (70 MPa): Cures to a material with strength exceeding that of most concretes, capable of handling significant structural loads.
- Superior Bond Strength: Delivers exceptional adhesion to a wide range of substrates, including 30 MPa tensile bond to steel and >3 MPa to concrete.
- High Impact Resistance: Specifically formulated to retain its strength and integrity after repeated dynamic loading and impacts, ensuring longevity in harsh service conditions.
- Simple 1:1 Mix Ratio: The user-friendly 1 to 1 mix ratio by volume simplifies preparation on site and minimises the risk of mixing errors.
- Generous Work Time (45 Minutes): Provides a practical 45-minute window at 25°C for the careful assembly and alignment of large or complex components.
The Megapoxy 69 Advantage
- Execute Flawless Vertical & Overhead Bonds: Apply with confidence knowing the adhesive will not slump, guaranteeing a full-strength bond in the most challenging orientations.
- Build and Repair with Superior Strength: Create bonds that are often stronger than the substrates themselves, delivering long-term structural reliability backed by ASTM-tested data.
- Achieve a Perfect, Seamless Finish: Use an invisible bonding solution for architectural timber and stone work, eliminating the need for unsightly mechanical fasteners.
- Rely on Proven Performance: Specify the same product used by Transport for NSW for critical heritage bridge repairs, a testament to its real-world durability and strength.
Applications in Practice: Trade Scenarios
For Remedial Contractors: Heritage Timber Bridge Repair
The Engineering Challenge: To repair large splits, holes, and rotted sections in the structural top chord of a high-traffic, heritage-listed timber bridge, requiring exceptional strength and impact resistance with minimal disruption.
The System-Based Solution with Megapoxy 69: After removing damaged timber, use Megapoxy 69 to seal all large holes and splits. Its non-sag gel consistency allows it to fill deep vertical voids without slumping, creating a high-strength, waterproof, and impact-resistant structural repair that restores the integrity of the timber member, as successfully executed on the Coolumbooka River bridge.
Best Practice Note: For maximum adhesion to aged or weathered timber, ensure all decayed material is removed back to a sound, solid base and the surface is free of contaminants.
For Stonemasons: Fabrication of Granite & Marble Structures
The Engineering Challenge: Assembling heavy granite or marble panels, countertops, or architectural features, requiring a permanent bond that is stronger than the stone itself and will not fail under stress.
The System-Based Solution with Megapoxy 69: Apply Megapoxy 69 to the edges of the prepared stone sections. Its 1:1 mix ratio is simple to prepare, and the 45-minute work time allows for careful alignment. The non-sag gel holds securely on vertical seams during the cure, resulting in a seamless, incredibly strong bond that is ready for polishing and finishing.
Best Practice Note: Ensure stone surfaces are clean, dry, and free of dust from cutting or grinding. Wiping with a solvent like acetone can improve adhesion on dense stone types.
Certifications & Regulatory Compliance
Megapoxy 69 is engineered to meet the highest performance benchmarks for structural adhesives. Its mechanical properties, including Compressive Strength (ASTM D695), Tensile Strength (D638), and Bond Strength (ASTM D4541, D897), are validated through independent ASTM testing. For metal preparation, it is recommended to grit blast to AS CK 9.4-1964 Class 3 finish. The formulation is Nil VOC (Volatile Organic Compounds) and all components are listed on the Australian Inventory of Chemical Substances (AICS).
Storage & Shelf Life Considerations
To ensure optimal performance and workability, Megapoxy 69 should be stored in a cool, dry place out of direct sunlight. Keeping the containers sealed when not in use will prevent contamination and moisture absorption. Following these storage guidelines is essential for the product to meet its specified high-performance characteristics on site.
Frequently Asked Questions About Megapoxy 69
Q: How 'non-sag' is it? Can I use it for a large overhead repair?
A: Megapoxy 69 is a true non-sag gel. It is specifically designed to be applied on vertical and overhead surfaces without dripping or slumping, even in thick sections. This makes it the ideal product for applications like filling deep cracks in walls, bonding components overhead, or repairing the underside of structures.
Q: What is the final cured colour?
A: Megapoxy 69 mixes to a light yellow, translucent colour. This makes it a suitable choice for bonding timber and some types of stone where a dark or opaque glue line would be visually disruptive. It is not a clear, water-white epoxy.
Q: What is the best way to prepare old or weathered timber for bonding?
A: For maximum adhesion, all decayed, soft, or contaminated wood must be mechanically removed back to a solid, sound substrate. The surface should then be sanded or abraded to remove loose fibres and expose fresh wood. Ensure the surface is completely dry and free of dust before applying the adhesive.
Q: Is the 1:1 mix ratio critical?
A: Yes, absolutely. The 1 part A to 1 part B mix ratio by volume is essential for the epoxy to cure correctly and achieve its specified structural properties, including its 70 MPa compressive strength. Inaccurate mixing can result in a weak bond or a failure to cure properly, compromising the entire repair.
Applications & Benefits
| Application / Use Case | Key Benefit | Primary Trades |
|---|---|---|
| Structural Timber Joinery | Creates bonds stronger than the timber itself; ideal for high-stress joints. | Carpenters, Joiners, Remedial Builders |
| Bonding Metal to Concrete | High bond strength (30 MPa to steel) for fixing plates, posts, and brackets. | Civil Contractors, Builders, Steel Fixers |
| Granite & Marble Assembly | Non-sag for vertical seams and creates a tenacious, permanent bond. | Stonemasons, Fabricators |
| Concrete Crack & Void Filling | Non-slump gel consistency fills large vertical cracks and holes securely. | Remedial Contractors, Concrete Repairers |
| Marine Environment Applications | Excellent chemical and water resistance for durable bonds in marine settings. | Boat Builders, Marine Trades |
Applying Megapoxy 69: Protocols & Best Practices
General Application Steps:- Preparation: Ensure all substrates are prepared to the required standard as per the Adhesion & Preparation Guide.
- Mixing: In a clean container, measure exactly 1 part of Part A and 1 part of Part B by volume. Mix thoroughly with a spatula or slow-speed drill mixer, scraping the sides and bottom of the container, until a uniform, streak-free light yellow colour is achieved.
- Application: Apply the mixed adhesive to the prepared surface(s) using a trowel or spatula. For bonding, apply to both surfaces if possible. Press the components firmly together to ensure full contact and squeeze out any entrapped air.
- Curing: Secure or clamp the assembly to prevent movement during the initial cure. Allow to cure for the minimum time based on ambient temperature (e.g., 24 hours at 25°C) before subjecting the bond to significant stress.
For Remedial Contractors: Heritage Timber Bridge Repair
The Engineering Challenge: To repair large splits, holes, and rotted sections in the structural top chord of a high-traffic, heritage-listed timber bridge, requiring exceptional strength and impact resistance with minimal disruption.
The System-Based Solution with Megapoxy 69: After removing damaged timber, use Megapoxy 69 to seal all large holes and splits. Its non-sag gel consistency allows it to fill deep vertical voids without slumping, creating a high-strength, waterproof, and impact-resistant structural repair that restores the integrity of the timber member, as successfully executed on the Coolumbooka River bridge.
Best Practice Note: For maximum adhesion to aged or weathered timber, ensure all decayed material is removed back to a sound, solid base and the surface is free of contaminants.
For Stonemasons: Fabrication of Granite & Marble Structures
The Engineering Challenge: Assembling heavy granite or marble panels, countertops, or architectural features, requiring a permanent bond that is stronger than the stone itself and will not fail under stress.
The System-Based Solution with Megapoxy 69: Apply Megapoxy 69 to the edges of the prepared stone sections. Its 1:1 mix ratio is simple to prepare, and the 45-minute work time allows for careful alignment. The non-sag gel holds securely on vertical seams during the cure, resulting in a seamless, incredibly strong bond that is ready for polishing and finishing.
Best Practice Note: Ensure stone surfaces are clean, dry, and free of dust from cutting or grinding. Wiping with a solvent like acetone can improve adhesion on dense stone types.
Limitations & Safety
Product limitations and safety information
Limitations:
- Minimum application temperature is 10°C. Do not apply if substrate or ambient temperature is below this threshold.
- The 1:1 mix ratio is critical and must be adhered to for proper curing and strength development.
- Working time is 45 minutes at 25°C. This time will be shorter at higher temperatures. Only mix what can be used within this window.
- This product is not UV stable and should be coated if used in applications with direct sunlight exposure.
Safety & Handling:
- PPE: Wear protective clothing, nitrile rubber gloves, and safety glasses/face protection at all times during mixing and application.
- Ventilation: Use in a well-ventilated area. Natural ventilation is typically sufficient for normal use.
- Handling: This product is a skin sensitiser and can cause serious eye damage. Avoid all contact with skin and eyes. If contact occurs, flush immediately with copious amounts of water.
- First Aid: Ensure eyewash stations are accessible. If skin irritation or a rash occurs, seek medical advice. Refer to the SDS for detailed first aid measures.
Megapoxy 69 Adhesion & Preparation Guide
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Substrate preparation guidelines
- Concrete: The surface must be structurally sound and free from grease, oil, and dust. Remove all surface laitance by mechanical means such as grinding, scabbling, or grit blasting to expose the aggregate. The concrete must be surface dry for maximum adhesion.
- Steel: For critical structural bonds, steel must be grit blasted to an AS CK 9.4-1964 Class 3 finish. If not possible, mechanically abrade the surface to a clean, bright metal finish. Immediately degrease the prepared surface by flooding with an industrial grade degreaser.
- Timber: Wood surfaces must be clean, dry, and free of oils or previous coatings. Sand or plane the surface to expose fresh, sound wood. Remove all sawdust before application.
- Coated Surfaces: Do not bond directly to painted, sealed, or galvanized surfaces. All coatings must be completely removed by paint stripper, flame cleaning, or grinding to expose the bare substrate for a reliable structural bond.
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