Summary for aluminium for watch cases Discussion
Aluminium for watch cases is discussed as a less common choice than brass because, as Guillermo Marrufo notes, bare aluminum is readily attacked by sweat and other environmental substances, so it would need a protective coating to survive skin contact. He adds that such coatings are difficult to apply well and would likely need to be thick and expensive, which is why brass or stainless steel are usually selected instead. On the question of finishing, the original poster asks whether conventional electroplating or PVD can be used on aluminum cases instead of anodizing, and which aluminum grade would be suitable. Leo Herringon offers a counterpoint by noting that anodizing has long been used for direct, continuous skin contact, citing older eyeglass frames as an example. The thread therefore suggests anodizing is the established route, while other coatings may be possible but are not presented as the usual solution.
Q. Why generally aluminium is not chosen as the base metal for watch case manufacturing compared to brass? Can we do plating by conventional electro plating route or PVD on aluminium cases other than anodizing ? If so which grade of aluminium is suitable for this?
Ramasubramanian Sankaran
plating shop employee – Bangalore
January 22, 2009
A. Aluminum is not suitable for contact to skin since it is readily attacked by sweat (salt) and many other substances in our environment. In order to eliminate this problem, a suitable coating would have to be applied to the aluminum. Since aluminum is difficult to coat properly and the available coatings would have to be somewhat thick and most surely expensive, another metal like brass or stainless steel is normally selected.
Guillermo Marrufo
Monterrey, NL, Mexico
January 30, 2009
A. Actually anodizing has been used extensively in direct and continuous skin contact. Years ago eyeglass frames were commonly anodized.
Leo Herringon
consultant – Grand Rapids, Michigan, USA
February 3, 2009