Crystic® Isophthalic
Brush Gelcoat 65PA

Product info

Crystic® Isophthalic Brush Gelcoat 65PA

High-Performance Isophthalic Gelcoat for Cosmetic & Structural Composite Surfaces

Crystic® Gelcoat 65PA is a high-performance, isophthalic polyester gelcoat formulated for brush application where surface finish, durability, and water resistance are critical. Pre-accelerated for ease of use, this gelcoat delivers consistent curing behaviour and excellent handling characteristics across a wide range of moulding conditions.

Designed for use across marine, land transport, building, and general moulding applications, Crystic® Gelcoat 65PA provides a smooth, high-gloss cosmetic surface with good flexibility and impact resistance. Its proven formulation has made it a long-standing choice for moulders worldwide seeking reliable processing, ease of repair, and long-term surface performance.

Crystic® Gelcoat 65PA is approved by Lloyd’s Register of Shipping, reinforcing its suitability for demanding marine and structural composite environments.

Key Features & Benefits

Isophthalic resin base

Excellent water resistance and reduced risk of blistering

High elongation characteristics

Improved impact resistance and durability in service

Excellent surface finish

Produces smooth, high-gloss cosmetic surfaces

Optimised for brush application

Easy handling and controlled application in production

Good flexibility & repairability

Suitable for general moulding and long-term maintenance

Lloyd’s Register approved

Suitable for glass fibre, carbon fibre, and aramid Trusted performance for marine applications

Applications

Crystic® Gelcoat 65PA is recommended for:

Marine mouldings
Hulls, decks, and marine components requiring durable cosmetic finishes
Land transport components
Panels and moulded parts with high surface quality requirements
Building & architectural mouldings
General composite moulding applications
Moulded components requiring ease of repair and long-term gloss retention

Processing & Application

Crystic® Gelcoat 65PA is pre-accelerated and formulated for brush application. It requires only the addition of a suitable MEKP catalyst to initiate curing.

Recommended catalyst: 2% Butanox® M-50 or equivalent
Recommended wet film thickness: 600–800 microns
Apply backing laminate once the gelcoat has reached the appropriate degree of cure, typically within 24 hours

Post curing is recommended to achieve optimum mechanical, thermal, and water-resistance properties prior to placing parts into service.

Mechanical & Thermal Properties (Cured)

(Post cure applied)

Tensile Strength: ~75 MPa
Tensile Modulus: ~3500 MPa
Barcol Hardness: ~42
Heat Deflection Temperature (HDT): ~75°C
Flexural Strength: ~126 MPa

Packaging & Availability

Packaging:
- Clear – 20 kg pail
- White – 25 kg pail
Storage:
Store in original, sealed containers at temperatures below 25°C.
Product must not be frozen.

ATL Technical Support
ATL Composites provides application guidance, catalyst selection advice, and infusion optimisation support to help ensure reliable processing and consistent laminate quality when using Crystic® VE 679-03PA systems.

Certifications / TDS

Lloyd’s Register of Shipping

Crystic® Gelcoat 65PA

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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