Crestafix® 621CC
BONDING PASTE

Product info

Crestafix® 621CC Bonding Paste

High-Performance Hybrid Urethane Acrylate Bonding Pastes for GRP Assembly

Crestafix® 621CC is a range of pre-accelerated, hybrid urethane acrylate / isophthalic bonding pastes engineered for the structural bonding and assembly of GRP mouldings. Designed to deliver high shear strength without the need for mechanical fixings, these systems provide a reliable alternative to traditional vinyl ester bonding pastes.

Formulated as non-sagging, filled compounds, Crestafix® 621CC bonding pastes allow controlled application on vertical or complex geometries while maintaining excellent gap-filling capability and long-term bond durability. The range is widely used across marine, transport, industrial, and general composite manufacturing environments where strength, productivity, and consistency are critical.

Key Features & Benefits

Hybrid urethane acrylate technology

High shear strength and durable structural bonds

Non-sagging, filled formulation

Excellent control on vertical and complex surfaces

Mechanical fastener replacement

Enables strong bonded joints without drilling or fixings

Pre-accelerated systems

Simple processing with MEKP catalyst addition only

Designed for GRP mouldings

Optimised adhesion to composite substrates

Improved production efficiency

Faster assembly with reduced finishing and rework

Product Variants

Crestafix® 621CC 45

Crestafix® 621CC 45 is a pre-accelerated hybrid isophthalic urethane acrylate bonding paste developed as a direct replacement for vinyl ester bonding pastes. It delivers high shear-strength joints while reducing the need for mechanical fastening, improving production efficiency and joint aesthetics.

This grade is particularly suited to general GRP bonding and assembly operations where balanced working time and strong structural performance are required.

Crestafix® 621CC 85

Crestafix® 621CC 85 is a higher-performance bonding paste formulated from a urethane acrylate / isophthalic polyester hybrid system. Designed for more demanding applications, it offers enhanced mechanical performance and durability while maintaining the same non-sagging, easy-to-apply characteristics.

This grade is ideal for heavily loaded joints, large mouldings, and critical structural assemblies where maximum bond performance is required.

Typical Applications

Crestafix® 621CC bonding pastes are recommended for:

Assembly of GRP mouldings
Structural bonding of composite components
Marine, transport, and industrial composite fabrication
Replacement of mechanical fixings in bonded joints
General composite manufacturing and repair

Processing & Application

tafix® 621CC bonding pastes are supplied pre-accelerated and require only the addition of a suitable MEKP catalyst to initiate cure.

Apply using spatula, trowel, or dispensing equipment
Designed for gap filling and controlled bond line thickness
Suitable for vertical and overhead applications due to non-sag formulation

Surface preparation is critical: substrates should be clean, dry, and free from contamination. Light mechanical abrasion is recommended to achieve optimum bond strength.

Application trials are recommended to confirm suitability for specific substrates and service conditions.

Packaging & Storage

Packaging: 20 Kg Pail
Storage:
Store in original, unopened containers in a cool, dry, well-ventilated area.
Protect from freezing and direct sunlight.

Technical Data Sheet

Crestafix® 621CC 85

ATL Technical Support
ATL Composites provides bonding paste selection advice, joint design guidance, and processing support to help ensure Crestafix® 621CC systems deliver reliable structural performance in composite assemblies.

frequently asked questions

How does ATL tailor composite systems for different industries?

Every industry has distinct performance, compliance, and manufacturing requirements. ATL’s in-house chemists and engineers develop and refine epoxy systems, adhesives, and core materials to meet the specific demands of marine, defence, aerospace, automotive, industrial, civil, architectural, and sporting applications — ensuring every product delivers optimal strength, efficiency, and durability.

Can ATL customise materials for my project or process?

Yes. ATL offers custom formulation and process engineering support to align material performance with your production requirements — whether infusion, hand lay-up, lamination, bonding, or CNC-routed panel construction. Our technical team collaborates closely with customers to deliver precision-matched resin systems and structural solutions for unique applications.

Are ATL’s composite systems certified for high-performance applications?

Absolutely. ATL operates under an ISO 9001:2015-certified quality management system, with selected materials approved by DNV for use in structural and high-load applications. Every ATL system is manufactured to exacting standards of performance, consistency, and traceability to meet the demands of defence, industrial, and advanced engineering environments.

What makes ATL’s materials suitable for large-scale or structural builds?

ATL’s epoxy systems, structural panels, and composite cores are engineered for high strength-to-weight performance, dimensional stability, and fatigue resistance. These attributes make ATL materials ideal for large composite assemblies, modular structures, and precision-engineered components where long-term strength, weight reduction, and reliability are essential.

Does ATL offer sustainable or bio-based composite options?

Yes. ATL is committed to advancing sustainable composite technology, offering USDA-Certified Bio-Based epoxy systems and environmentally conscious materials that reduce waste, extend service life, and minimise environmental impact. Our ongoing R&D focuses on improving sustainability without compromising structural integrity or mechanical performance.

How can I select the right ATL system for my application?

Choosing the ideal composite system depends on your structure’s design, load requirements, manufacturing process, and environmental exposure. ATL’s in-house engineers and chemists provide tailored advice to ensure the correct combination of resin, core, adhesive, and surface technology for your project.
To discuss your application or request technical guidance, contact ATL’s Technical Team — we’ll help you identify the most effective and efficient composite solution for your build.

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