The CityLink Red Sticks create an iconic entrance to Melbourne for motorists approaching the toll road from the city's north.

However, red paint is notorious for fading and the previous non-Dulux coatings only lasted three years before needing a recoat.

Based on their understanding of the local environment, and the severe impact of UV light in this environment, the Dulux Protective Coatings Research & Development team developed a special custom formulation that would endure the UV exposure.  This custom formulation not only achieved a more lasting colour but also achieved improved opacity to improve application of the product.

Project partners

• Asset owner: Transurban
• Applicator: Mattioli Bros

Coatings

The 39 steel columns were repainted with a surface tolerant base followed by a customised topcoat in CityLink Cherry Red.

• Spot Primer: Dulux® Zincanode® 402 applied after rust removal.
• First coat: Dulux® Durebild® STE at 80-microns (µm).
• Topcoat: Dulux® Weathermax® HBR custom made with the Cherry Red formulation for maximum added UV stability. Applied at 80-microns (µm).

What was the challenge?

Originally fabricated in 1999, the Red Sticks had been repainted in the mid 2000s. Within a few years, the non-Dulux coatings had experienced significant colour fade. Under high UV exposure, the north and west faces had dulled from red to pink. There were also isolated patches of delamination.

Transurban approached Dulux® Protective Coatings for a new system to extend the maintenance cycle. A brush and roller application was required, due to the complexity of painting the angled columns from cherry pickers and the unacceptable risk of over spraying onto traffic.

While bright red typically requires multiple coats, customising Weathermax® HBR delivered value and performance: achieving outstanding UV protection and high opacity in a single topcoat.

What were the inspection findings? 

After five years, the CityLink Cherry Red colour was found to be intact. The coatings were in good condition with good integrity.

Using the Delta E scale of 0 to 100, the change in colour was measured at a maximum of 2.5 on the north and west faces after five years.

Coating rating after 5 years

Rating 1*

Up close

"Bright red is a difficult colour to achieve high opacity in a single coat. It's also more UV sensitive and therefore prone to fading. Our lab developed a UV-stable custom colour. This solution has resisted fading for a much longer period than the previous red," says Daniel McKeown, Dulux Protective Coatings Business Development Executive, Victoria.

System benefits

Each coating combined to deliver superior weathering performance and extend the maintenance cycle.

• Fast-drying Zincanode 402 offers corrosion protection in rust-prone areas
• Adhering well to pre-existing coatings, Durebild STE is an excellent barrier protection for steel. It is also corrosion resistant and ideal for brush and roller application
• Weathermax HBR is proven to deliver extended service periods and colour retention, even in extreme UV exposure
• The CityLink Cherry Red custom formulation created a deeper, more lasting red in a single coat
• The topcoat has been developed for high build roller or brush application, with improved opacity saving the applicators a second coat

* Coating Inspection 5-Level Rating System

Coatings are inspected to determine the degree of deterioration. Ratings indicate the following condition status:

1. No film damage other than dirt and minor staining
2. Soiled, stained, ingrained dirt, chalking or loss of gloss
3. Minor film damage (cracking, flaking or erosion of topcoats) in small areas
4. Minor corrosion where up to 0.5% of the base metal is showing signs of rusting
5. Widespread and excessive corrosion and damage