Triple Process Coating

Form meets function

Triple Process Coating is our recommended finish system for steel products on which a high quality finish is equally as important as corrosion resistance and durability. Here’s how we do it.

Shot blasting

Step 1

Prior to the application of any paint or powder coating, it is essential to remove any mill scale, oil, dirt, oxidation and welding scale that can cause adhesion issues, give an uneven coating or contaminate the primer or finish coats.

The most effective way of cleaning steel products is by mechanical shot blasting, whereby abrasives are blasted at the product to not only clean the surface but also to provide surface texturing that aids adhesion of the protective primer onto the steel. Our products are shot blast to standard SA 2.5, which ensures all contaminants are removed.

Protective primer

Step 2

With the product’s surface cleansed and decontaminated, we apply a protective primer, as a free-flowing dry powder using an electrostatic spray gun process, which ensures even coverage and therefore a high quality substrate between the cleaned steel and the final polyester top coat.

The steel product is heated to 200°C and the powder is cured on to the surface to a minimum film thickness of 80 microns. It is the primer application that provides the long term corrosion resistance to the product.

PPC finish coat

Step 3

The polyester powder finish coat provides a decorative coloured finish on top of the protective primer, to a minimum film thickness of 80 microns, electrostatically applied and cured onto the product. As standard we offer the RAL Classic system, with a choice of 215 colours and a gloss levels from matte, to satin and full gloss. Other specialist colour systems and finishes are available on special request.

Testing

Independently tested and approved

We have commissioned an independent laboratory test with a global powder manufacturer in Austria to assess the performance of our Triple Process Coating system. A 2,000hr salt water test concluded that there was no discernable delamination of the primer or finish coats from the steel substrate. We are confident that our Triple Process Coating offers a high aesthetic quality, is robust and resistant to corrosion, and as such is ideal for the demanding site conditions in which our products are placed.

Advantages over galvanised + PPC finish system

Traditionally, we have offered hot dip galvanising as the anti-corrosion treatment on steel products, with the option of a supplementary PPC coat where a colour finish is required. Whilst the protective properties of galvanising are great, the significant compromise is that the quality of the surface finish can be variable, often with highly visible drips, pitting and other imperfections – which you can avoid with our triple process coating.

Other potential drawbacks of the galvanising process include distortion (resulting from the extremely high temperatures of the molten zinc) and the need for often unsightly vent holes on the product to allow the zinc to escape.

Galvanising undoubtedly still has its place though, for example on more rudimentary and less aesthetically prominent products such as bollards and railings, but on higher value products that may also subject to closer personal interaction, such as seating, the Triple Process Coating is now our preferred finish system.