What is Anodisation?

Anodization. What is it, and how do we use it to make the whole range of colours you see in our aluminium ranges?

Anodization is an electro-chemical process used to increase the thickness of a metal’s natural oxide layer while also making the outer layers more porous. This makes the surface of the metal more resistant to wear and corrosion while also allowing it to absorb dyes and other materials more readily. This is how we get the super vibrant colours in our aluminium dice – especially evident in our Pollock ranges.

The process for anodization was first commercialized in 1923 in the development of seaplanes – they needed a way to make the aluminium used in the planes more resistant to the natural mildly corrosive sea-salt the planes were constantly exposed to. Over the years the process has been added to and refined, with many different variations on techniques implemented by different manufacturers to for various other applications for anodization, ranging from kitchen appliances to architecture. The development of stronger plastics and powder coating has made anodization less common in these applications – however, the strength and greater precision compared to other materials and processes makes anodization still a preferred method of colouring highly precise equipment. As one would imagine, that’s why we use it in the production of our precision cut aluminium dice.

So how does anodization actually work?

Anodization is named as such because it treats the metal being treated as an anode electrode (electricity travels into it from an outside source). The metal is suspended in an acid bath, and then a current is passed through the bath into the metal being anodized. This literally infuses the dyes into the metal as it oxidizes, meaning there’s no way to remove the layer of colour without stripping the metal itself. Depending on a whole range of factors like the type of acid used, the voltage of the electricity, the temperature of the bath, the dye used in the bath – to name a few – the surface of the metal oxidizes while absorbing the ‘impurities’ in the bath, effectively soaking up the dyes being used to colour the metal.

By very carefully managing and controlling all of these variables we’re able to create all the super vibrant ranges of colours you find our dice in. Using a couple of extra little tricks we’ve learnt along the way, we’ve developed the processes that let us make all the impressive colour combinations you see in the dual colour dice, triple colour dice and Pollock dice ranges.

One of the biggest challenges with anodization is that the process, in making the surface of the metal more porous, also makes it more susceptible to internal corrosion. We use two processes to combat this; hardened anodization and sealing. Hardened anodization uses a special sulfuric acid bath at much lower temperatures than regular anodization – which makes the surface oxidation much thicker as well as hardening it (hence the name). This makes it much harder to wear away the outer colouring. Then the finished product is given a special sealant layer that closes up the porous surface, stopping the inner layers of the metal from corroding any further. That’s how we ensure the dice stay pristine, and keep their perfect balance even through years of use.

And there we have it, a quick explanation of how anodizzation works and why we use it to make our precision-cut aluminium dice!

If you found any of this interesting, be sure to check out our aluminium dice range, or have a look at our other metal dice, all given their own special precision machining to keep them as perfect as our aluminium are.