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Unobond FC Blue: A Technical Overview
Unobond FC Blue is a solvent-free, moisture-curing polyurethane adhesive formulated for structural bonding in demanding environments, including marine and external timber applications. Its high-performance chemistry offers a strong, durable bond to a broad range of substrates such as wood, metals, concrete, masonry, foams, and many plastics. With a long open time of 40 minutes and a pressing time of 1.5 hours at 20°C, it provides trades with flexibility during setup without compromising cure speed. Temperature resistance from -40°C to +100°C ensures integrity across Australian climate zones. A slight expansion during cure helps fill substrate irregularities, creating a solid structural join, even under imperfect jobsite conditions.
Core Features & Specifications
- Moisture-curing formulation – activates with ambient humidity for hassle-free setup
- 40-minute open time – provides flexibility for large surfaces or complex assemblies
- Pressing time of 1.5 hours at 20°C – allows for efficient clamping cycles
- Temperature resistance from -40°C to +100°C – ideal for hot sheds or cold storage applications
- 7.5–10 m² per litre coverage – high efficiency with minimal waste
- Highly water-resistant bond – suitable for marine and external timberwork
The Unobond FC Blue Advantage
- Reduces jobsite failures by bonding reliably across dissimilar materials
- Minimises rework with a slight foaming action that fills substrate imperfections
- Eliminates the need for primers on most surfaces—saving time and cost
- Performs in both hot and cold conditions, perfect for Australian site variability
- No mixing or complex handling required—simply apply, press, and go
- Supports long-term durability for structural applications subject to weather and movement
Best Practices: Do's & Don'ts
Do
- Ensure at least one surface contains moisture for proper curing
- Clamp, screw, or nail the bonded surfaces during curing to ensure even pressure
- Clean surfaces thoroughly of dust, grease, and contaminants
- Use acetone or MEK for cleaning uncured adhesive
Don't
- Use as a gap filler where structural load-bearing is critical
- Rely on high-pressure clamping—light uniform pressure is sufficient
- Apply to non-porous substrates without surface preparation
- Expose to freezing temperatures during storage or application
Applications in Practice: Trade Scenarios
For Builders (On-Site Applicator): Timber-to-Masonry Structural Bonds
The Engineering Challenge
Timber beams or battens need to be securely fixed to masonry walls in outdoor or semi-exposed conditions. Adhesives must resist both moisture ingress and thermal movement across seasons.
The System-Based Solution with Unobond FC Blue
Apply a continuous film (approx. 150 g/m²) using a roller. Lightly mist the surface (10–15 g of water per 100 g adhesive) to accelerate cure. Press timber into position and screw fix for clamping. Cures in 90 minutes at 20°C.
Best Practice Note
Use temporary spacers to maintain joint alignment during curing. Avoid over-wetting as this may cause foaming and joint displacement.
For Carpenters (On-Site Applicator): Laminated Timber Panel Assembly
The Engineering Challenge
Joining large timber sheets with minimal fasteners requires high bond strength and a forgiving open time to adjust alignment without rushing.
The System-Based Solution with Unobond FC Blue
Spread adhesive evenly at 7.5–10 m²/L. Position the panels and use mild clamping across the full area. Cure for 90 minutes before moving. Excess adhesive can be trimmed after 2 hours.
Best Practice Note
Avoid applying on very hot days (>35°C) without shade, as rapid skinning may reduce bond strength. Pre-fit components before adhesive application.
For Glaziers (Remedial Specialist): Foam Panel Fixing to Metal Frames
The Engineering Challenge
Fixing foam insulation panels to aluminium frames in curtain wall applications demands strong adhesion without damaging the substrate or melting foam surfaces.
The System-Based Solution with Unobond FC Blue
Apply a light film using a spreader or bead gun. Lightly mist to accelerate. Press into place and brace for 1.5 hours. Cure will not damage or degrade EPS or XPS foams.
Best Practice Note
Roughen aluminium with 120-grit abrasive and solvent-wipe prior to bonding for optimal results.
Performance Benchmark: Unobond FC Blue vs. Standard Alternatives
| Metric | Unobond FC Blue | Standard Alternative | Advantage |
|---|---|---|---|
| Open Time | 40 min Extended workability | 10–15 min | Easier handling on large assemblies |
| Temperature Resistance | -40°C to +100°C Extreme tolerance | 0°C to +70°C | Reliable in hot sheds and cold storage |
| Water Resistance | High Marine suitable | Moderate | Suitable for exterior and wet areas |
Frequently Asked Questions
What is Unobond FC Blue used for in construction?
Unobond FC Blue is a high-performance structural adhesive ideal for bonding timber, foam, masonry, metals, and plastics. It is used in general construction, timber framing, panel laminating, and even marine environments where moisture resistance and strong adhesion are critical.
How long does Unobond FC Blue take to cure?
The typical pressing time is 1.5 hours at 20°C with full structural strength developing after complete cure. A light water mist (10–15g per 100g adhesive) can be sprayed to accelerate curing in low-humidity conditions.
Can Unobond FC Blue be used on non-porous surfaces?
Yes, but surface preparation is essential. Non-porous substrates like aluminium or PVC should be lightly abraded and wiped with solvent. In some cases, Primer 50A is recommended for critical applications.
Is Unobond FC Blue suitable for marine applications?
Yes. Unobond FC Blue is highly water-resistant and has been formulated to perform in marine and external timber environments. It resists swelling, degradation, and thermal cycling common in boat building and dock construction.
What’s the best way to clean up Unobond FC Blue?
While the adhesive is still wet, use Acetone or MEK to clean tools and surfaces. Once cured, Unobond FC Blue can only be removed mechanically by trimming or sanding. It is essential to clean immediately after use for best results.
Applications & Benefits
| Application / Use Case | Key Benefit | Primary Trades |
|---|---|---|
| Timber-to-Masonry Bonding | Reliable adhesion on damp or porous substrates | Builders, Carpenters |
| Foam Panel Fixing to Metal Frames | No melting or degradation of insulation foams | Glaziers, Facade Installers |
| Marine Joinery & Deck Bonding | Highly water-resistant and weather-tolerant bond | Boat Builders, Joiners |
| Exterior Timber Cladding Installations | Withstands temperature cycling from -40°C to +100°C | Builders, Cladding Installers |
| Laminating MDF, Particleboard & Veneer Panels | Extended open time for precision alignment | Cabinetmakers, Joiners |
Applying Unobond FC Blue: Enhanced Protocols & Best Practices
-
Step 1: Surface Preparation
Ensure surfaces are clean, dry, and free from dust, oil, grease, or loose particles. For metals, abrade and wipe with acetone. For porous materials, confirm moisture content is below 30%.
Porous Substrates
Clean with vacuum or brush. Dampen slightly if substrate is bone dry to support cure.
Non-Porous Substrates
Lightly sand or scuff with 120-grit, then solvent-wipe (acetone or MEK).
Timing: Complete prep immediately before bonding for best results.Pro Tip: Use lint-free cloths and clean gloves to avoid surface contamination. -
Step 2: Adhesive Application
Apply an even coat of Unobond FC Blue using a glue spreader, roller, or spray applicator at a coverage rate of 7.5–10 m² per litre.
Bead Application
Lay continuous beads every 150–200 mm for panel fixing. Avoid gapping.
Full Coverage
Use a roller or spreader for sheet-to-sheet bonding to maximise contact.
Timing: Apply and press within 40 minutes to maintain optimal open time.Pro Tip: For faster cure, lightly mist with 10–15 g of water per 100 g adhesive. -
Step 3: Pressing & Fixing
Bring both surfaces together immediately. Apply uniform pressure by clamping, nailing, or screwing to maintain contact during curing.
Manual Clamping
Apply light but uniform pressure for 1.5 hours at 20°C. Do not overtighten.
Temporary Screwing
Use fixings to hold parts during cure. Remove or leave as part of assembly.
Timing: Pressing time: 1 hr 30 min at 20°C. Longer at lower temps.Pro Tip: Avoid repositioning once materials are pressed. Ensure alignment is correct. -
Step 4: Cleanup & Finishing
Clean tools and surfaces with Acetone or MEK before adhesive cures. Once cured, Unobond FC Blue must be removed mechanically by trimming or sanding.
Wet Adhesive
Wipe with solvent immediately after application. Avoid excessive rubbing on porous surfaces.
Cured Adhesive
Trim flush with chisel or sanding block. Do not use heat or harsh chemicals.
Timing: Clean before skinning begins — typically within 20–30 minutes depending on ambient humidity.Pro Tip: Use disposable brushes or tools when possible for quick cleanup.
Limitations & Safety
Product Limitations
Do not use as a primary gap filler—structural strength is reduced in thick beads.
Requires one substrate to contain moisture for proper curing; dry-to-dry surfaces may delay cure.
Not suitable for polyethylene, Teflon, or silicone-based plastics.
Use Adheseal Sili-Flex for silicone bonding applications.
Application should not occur below 5°C or above 35°C ambient temperature.
Unobond FC is not UV stable and should not be exposed where surface durability or appearance is critical.
Topcoat with UV-stable finishes if required.
Safety & Handling Requirements
Personal Protective Equipment
Wear nitrile gloves, safety glasses, and long sleeves to avoid skin contact. Sensitive individuals may experience irritation or sensitisation. Wash thoroughly after handling.
Ventilation Requirements
Use in well-ventilated areas. Ensure air exchange in enclosed spaces. Do not inhale vapours. Not recommended for confined applications without airflow.
Fire & Handling Precautions
Product is non-flammable in cured form. Avoid ignition sources during application. Store away from heat and open flame. Always replace lid tightly after use.
Emergency First Aid
Eyes:
Flush immediately with water for at least 15 minutes. Seek medical attention.
Skin:
Wash with soap and water. Remove contaminated clothing. Do not use solvents on skin.
Inhaled:
Move to fresh air. Keep warm and at rest. Seek medical attention if symptoms persist.
Swallowed:
Do not induce vomiting. Rinse mouth and give water. Seek immediate medical attention.
Seek medical attention immediately in all cases of serious exposure.
Unobond FC Blue Application Guide
Timber, MDF & Particleboard
Surface Preparation
Ensure surfaces are dry (max 30% humidity), clean, and free from dust, oil, or old adhesive. Light sanding recommended for oily hardwoods.
Primer Requirements
No primer typically required
Suitable for direct application on most internal/external timber types.
Concrete, Brick & Masonry
Surface Preparation
Remove laitance, dust, and loose particles. Dampen with water if surface is dry and porous. Avoid standing water.
Primer Requirements
No primer typically required
Moisture in substrate assists cure; ensure consistent dampness without pooling.
Aluminium, Steel & Sheet Metal
Surface Preparation
Lightly abrade with 120–180 grit and solvent-wipe using acetone. Ensure surface is dry and non-greasy before bonding.
Primer Requirements
Primer recommended for optimal adhesion
For critical or high-load applications, apply Primer 50A prior to adhesive.
Insulation & Polystyrene Foam
Surface Preparation
Clean foam face gently to avoid damage. Avoid solvents. Dry brushing is recommended. Do not compress foam during cure.
Primer Requirements
No primer typically required
Adhesive does not degrade EPS or XPS. Use in well-ventilated areas.
Melamine & Plastics (Selected Types)
Surface Preparation
Clean thoroughly with alcohol-based degreaser. Light abrasion may assist adhesion. Perform adhesion test before use.
Primer Requirements
Primer recommended for optimal adhesion
Use Primer 50A for dense or low-energy plastics (e.g., HDPE, polypropylene).
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