WEST SYSTEM 400 Fillers

Product info

WEST SYSTEM® Fillers

WEST SYSTEM® fillers enhance the versatility of the epoxy system by modifying the mixed resin’s consistency to suit a wide range of bonding, filling and fairing applications. Each filler is engineered with specific physical characteristics, and can be broadly classified into two categories: Adhesive (high-density) and Fairing & Filling (low-density).

High-density fillers produce strong, structural mixtures that cure to a hard, high-strength solid — ideal for bonding, hardware installation, filleting and applications where load-bearing performance is essential.
Low-density fillers create lightweight, easily sanded mixtures used for shaping, cosmetic filling and fairing, delivering smooth contours and a refined finish with minimal effort.

Common WEST SYSTEM® fillers include:

410 Microlight – ultralight fairing
411 Microsphere Blend – filleting and gap filling
413 Microfibre Blend – structural adhesive
417 Low Density Fairing Filler – general-purpose fairing

In select cases, ATL Composites also supplies alternative fillers to those listed in the WEST SYSTEM® User Manual to better suit specific customer requirements and manufacturing processes.

– Customise Performance. Control Every Surface.

WEST SYSTEM 400 FILLERS

410 Microlight

410 Microlight is the ideal low-density filler for creating a light, easily-worked fairing compound especially suited for cosmetic or surface applications like shaping, filling or fairing. 410 Microlight mixes to a very smooth creamy texture that can be trowelled to a feather edge, and is less porous than other filling compounds.

Pack Size

4 Litre | 12 Litres | 20 Litres

411 Microsphere Blend

411 Microsphere Blend is a low density filler which cures to a lightweight filling putty with excellent filleting characteristics. 411 Microsphere Blend is also used as a low density adhesive for edge gluing in strip plank construction.

Pack Size

4 Litre | 12 Litres | 20 Litres

413 Microfibre Blend

413 Microfibre Blend is a high density filler used to create a multi-purpose, high strength adhesive used for structural applications like bonding, filleting and hardware bonding, while retaining excellent wetting and penetrating capabilities. As a blended filler, 413 Microfibre Blend, offers an added degree of thixotrophy and substantially improved spreading and working properties.

Pack Size

4 Litre | 12 Litres | 20 Litres

417 Low Density Filler

417 is a low density microballoon-based filler used as a thickening agent with epoxy fairing systems to make fairing putties that are easy to sand or carve. 417 has a reasonably strong strength to weight ratio, and is recommended as the preferred filler under dark coloured surfaces.

Pack Size

4 Litres

USA WEST SYSTEM® Fillers	Australian WEST SYSTEM® Fillers	Applications
403 Microfibres	413 Microfibre Blend	Structural bonding
404 High Density	413 Microfibre Blend	Hardware bonding
405 Filleting	411 Microsphere Blend	Filleting and edge gluing in strip planking
406 Colloidal Silica	413 Microfibre Blend	Structural bonding
407 Low Density Filler	417 Low Density Filler	Fairing under dark coloured paints
410 Microlight	410 Microlight	Fairing under light coloured paints

WEST SYSTEM 410 Microlight

WEST SYSTEM 413 Microfibre Blend

WEST SYSTEM 411 Microsphere Blend

WEST SYSTEM 417 Low Density Filler

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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