Here at Moddex, we are always looking for a better way; how we can make things safer, easier, and long-lasting. We aim to look ahead of the world’s industries and understand what that means for the pathways we’re making safe. This forward-thinking has resulted in the creation of our product innovations, but in this article we’re taking a closer look at a smaller innovation that has had a big impact; our G390™.

Hot-dip galvanizing (HDG) is a well-established method for protecting steel structures from corrosion. However, Moddex has advanced this technology significantly with G390™, their proprietary coating primarily used in their Tuffrail products. G390™ represents applying HDG390 specifications to Moddex’s steel tube. This innovative process provides an increased corrosion resistance and longevity compared to industry standards. In this guide, we explore G390™’s extensive benefits and why more and more specifiers are choosing Moddex.

What Makes G390™ Revolutionary?

G390™ goes beyond ordinary galvanizing. By leveraging HDG390 specifications, Moddex elevates its coating process to achieve superior levels of coating thickness, metallurgy, and corrosion resistance. The result is a galvanized coating that is up to 3 times more durable compared to standard HDG coatings, offering superior protection in harsh conditions, ensuring long-lasting value.

Higher Coating Thickness
G390™’s coating is around 13 microns thicker than the standard HDG coating, which provides a substantial barrier against corrosion and G390™ to better resist damage from wear and tear during use and installation.

Enhanced Zinc Alloy
The zinc alloy used in G390™ is modified with small amounts of aluminium and silicon. This enhanced zinc alloy has a tighter, denser crystalline structure that inhibits the penetration of corrosive elements. The result is a galvanized coating that remains intact for much longer.

Extended Service Life
Combined, G390™’s thicker coating and enhanced zinc alloy translate to significantly longer service life and corrosion resistance. Moddex estimates that properly installed G390™ products can offer up to 50 years of protection and longevity in many applications.

Comparing G390™ to Industry Standards

To appreciate G390™’s groundbreaking nature, we must understand the industry standards within the hot-dip galvanizing process:

AS/NZS 4680 focuses on hot-dip galvanized (zinc) coatings on fabricated ferrous articles. It applies to articles that have been fabricated into a finished product before galvanizing and is concerned with ensuring that all parts of the steel article are fully protected from corrosion​​.

AS/NZS 4792 is specific to hot-dip galvanized (zinc) coatings on ferrous hollow sections, which can be applied by either a continuous or a specialized process. It covers hollow sections galvanized on both surfaces in a specialized plant, sections produced by welding pre-galvanized steel strip, and sections galvanized on external surfaces only, using a continuous process. This standard specifies requirements for the mass, quality, and testing of the galvanized coatings​​.

Moddex’s G390 product is created on a foundation of AS/NZ4792, but its additional protective layer ensures that AS/NZ 4680 standards can also be met. This is particularly useful in projects at scale, where many kilometres of handrail may be required in harsh environments – using a product like Moddex’s Tuffrail (with G390) means you can rest ensured in meeting and exceeding compliance standards, whatever the challenge.

Corrosion challenges all industries using steel for structures of any kind. Moddex developed G390™ to address this problem comprehensively. A data-driven comparison between HDG390 and standard HDG300 across categories shows G390™’s clear advantages. The below graph illustrates G390™’s consistently longer service life in all conditions.

Selected corrosivity category & calculated life (min-max years):



One compelling example of Moddex’s G390™ in action is showcased in their project in Antarctica, where extreme environmental conditions posed significant challenges for infrastructure durability. Here, Moddex’s innovative approach to corrosion protection proved instrumental in ensuring the safety and longevity of structures in one of the harshest environments on Earth. This real-world application underscores the effectiveness and reliability of G390™ in even the most extreme conditions, demonstrating its ability to keep people safe in challenging environments. Read more about Moddex’s project in Antarctica here.

Benefits of G390™

With service life extension in every category, G390™ ensures structures perform optimally in even the harshest environments such as marine environments, coastal/offshore structures and wastewater treatment facilities. Its longevity yields reduced maintenance costs and downtime for long-term savings. G390™ also promotes sustainability through increased structure lifespan and fewer replacements, benefiting both business needs and the environment. In corrosion protection, G390™ establishes a new pinnacle of innovation, reliability and value.​

G390™’s extensive benefits are summarized below:

  • Longer service life: G390™ provides a longer service life compared to AS/NZ 4792 hot-dip galvanized tube due to its thicker zinc coating. This results in reduced maintenance and replacement requirements.
  • Lower maintenance costs: G390™’s longer service life means less maintenance and replacement over the life of structures. This translates to significantly lower costs for asset owners.
  • Improved sustainability: G390™ reduces the need for replacements, conserving resources and minimizing environmental impact through a smaller carbon footprint.
  • Superior aesthetics: G390™’s thick, even zinc coating results in a smooth, uniform finish that maintains an attractive appearance for longer.

Moddex is committed to developing innovative corrosion protection technologies that help customers achieve their goals for durability, sustainability, and reduced costs. G390™ from Moddex provides better corrosion protection, longevity and value for all applications requiring galvanized steel tubing. Its innovative HDG390 process produces a product that exceeds performance requirements and economic needs. Talk to our expert team today to discuss how you can use the G390™ advantage on your project.