1) Made-to-order option 2 selected: the aluminum colors
This is Paul. As promised, I am coming back today to present the second article in a series dedicated to our made-to-order headphones. We first introduced our leather, how it’s made, and where it comes from. Today, we are going to talk about the aluminum and, more specifically, about its anodizing.
I will take a moment to remind you of the most recent poll of our options for personalization:
Link to survey: http://journal.aedle.net/2018/04/25/bespoke-survey/
2) The Anodization of Aluminum and its alloys
The second critical piece of our headphones, the aluminum cup, is a result of a process that is known as anodization or anodic oxidation. Aluminum is a lightweight metal, highly malleable, and resistant to corrosion. However, in its raw state, it is soft and has impurities. Anodizing gives the part concerned protection against wear and corrosion due to oxidation by carrying out the latter in a controlled environment (aluminum oxidizes spontaneously upon contact with air). The oxide layer that covers aluminum is called alumina; it is a very hard, uniform, transparent and insulating body.
To anodize aluminum, one proceeds in the same way as for the electrolysis of water (a phenomenon caused by the passage of an electric current in the water, cf diagram below). There are, however, some differences: the workpiece is the anode (negative potential in yellow below) and an ionic solution (sulfuric acid most of the time) is used, pure water being non-conductive. Due to the electric current, the water molecules are decomposed into hydrogen and oxygen; the surface of the workpiece is therefore directly exposed to the oxygen formed by the decomposition of the water, resulting in the formation of alumina.
The electrolytic treatment produces a much thicker layer of alumina than during the natural oxidation process (1). The structure of the aluminum is porous and allows the electrolyte to conduct the current to the metal. Once the anodizing is carried out, we go to the staining step (2) and finally to the sealing of the pores present in the alumina in order to reinforce its resistance (3). This last step is done in boiling water or steam in general, but can also be done cold.
3) aëdle aluminum
To obtain a perfect rendering, we chose the T-6063 aluminum, low alloyed with magnesium and silica, frequently used in aviation and architecture. It is ideal for machining complex shapes and its clean, smooth surface is particularly suitable for anodizing. In order to achieve the desired result with regard to our “cups”, it is necessary for us to perform aluminum machining in the mass, piece by piece.
4) Choice of available aluminum colors for the VK-X
I invite you to read this other article dedicated to the choices we made in terms of aluminum colors for the VK-X:
All this was a bit technical so please do not hesitate to ask questions and we will be happy to answer!