Anodized Thickness Classes & Corrosion Prevention (AS 1231)
Anodizing is an electrochemical process that converts the aluminium metal surface into a durable, corrosion-resistant anodic oxide finish. Under the Australian Standard AS 1231, anodized coatings are classified into thickness classes that determine performance and lifetime durability.
Anodized Thickness Classes
The thickness of the anodic oxide layer is measured in microns (\mu m). Different thickness classes are required based on environmental exposure:
- AA10 (10 microns): Light duty. Suitable for indoor applications or dry, non-polluted rural settings.
- AA15 (15 microns): Medium duty. Suitable for standard urban residential windows and doors.
- AA20 (20 microns): Heavy duty. Required for commercial storefronts and areas close to industrial sites.
- AA25 (25 microns): Extra heavy duty. Mandatory for seaside/coastal zones (within 100 meters of the high-tide line) and highly corrosive industrial environments.
Increasing the anodized film thickness from 15 to 25 microns increases corrosion resistance and resistance to sand abrasion by more than 2.5 times, ensuring structural aluminium framing stands up to harsh QLD coastal breezes.
Anodizing Quality Check Parameters
| Thickness Class | Min Average Film (μm) | Acid Dissolution Test Limit | Maintenance Interval |
|---|---|---|---|
| AA15 (Standard Clear) | 15 microns | < 30 mg/dm² weight loss | Every 6 Months |
| AA20 (Commercial Shopfront) | 20 microns | < 25 mg/dm² weight loss | Every 12 Months |
| AA25 (Heavy Marine Duty) | 25 microns | < 15 mg/dm² weight loss | Every 24 Months |
EPDM Seals and Maintenance Advice
To maximize the lifespan of anodized framing, all glazing slots are fitted with high-density EPDM rubber seals rather than standard PVC gaskets, as PVC degrades under UV exposure, releasing chlorine which attacks the anodic layer.
Anodized framing should be washed periodically with warm water and a mild, neutral detergent to remove accumulated salts. Abrasive cleaners should never be used, as they can scratch and compromise the protective oxide seal.
Document Stats
Topic: Surface Finish
Audience: Quality Managers
Standard: AS 1231:2000
Workshop: Slacks Creek, QLD
Frequently Asked Questions
How is the quality of our Insight 6 system verified?
All our Insight 6 components undergo strict Vickers hardness indentation testing and dimensional tolerance checks in compliance with AS/NZS 1866:1997 standards.
What warranties apply to our Insight 6 range?
We provide a 10-year structural warranty on all architectural profiles in the Insight 6 range, backed by Dulux accredited powder coat finishes.
Are CAD drawings available for Insight 6?
Yes, we provide 3D models (STEP format) and 2D CAD layouts (DWG/DXF) to support builders and designers during the project planning stage.
Related Projects & Case Studies
Slacks Creek Insight 6 Installation
Engineering and assembly of high-strength Insight 6 framework designed to satisfy local Region B wind ratings.
Gold Coast Commercial Insight 6 Project
Volume supply and custom CNC processing of Insight 6 profiles matching QBCC structural regulations.
Request Engineering Specification
Submit your project dimensions, wind zone parameters, or target specs. Our Slacks Creek team will review and reply within 24 hours.
Extended Scientific Review & Materials Engineering Discussion
Materials science plays a crucial role in architectural aluminium engineering. For clear-anodized profiles, the oxide layer (Al2O3) is established using an electrochemical acid bath. The anodizing thickness (AA15 or AA25) establishes a barrier against marine salt corrosion. The AA25 marine-grade class specifies a 25-micron thickness, which is highly resistant to coastal weathering and chalking under salt spray environments.
For double-glazed joinery, thermal performance is evaluated using overall frame U-values and solar heat gain coefficients (SHGC). Our high-performance suites incorporate polyurethane thermal breaks crimped between the inner and outer aluminium profiles. This thermal barrier stops heat conduction through the frame, reducing cooling loads. When combined with double glazing (6mm Low-E outer - 12mm Argon cavity - 4mm inner), frame U-values are reduced to 1.85 W/m²·K, ensuring energy efficiency.
For electrostatic powder coating, the thermoset polymer must achieve complete cross-linking during baking. Our lab performs MEK solvent rub tests to verify that the coating is fully cured. By matching materials testing with localized QLD building regulations, our technical reviews provide builders and design professionals with verified structural specifications.