Thursday, February 27, 2014

Ductility


Signature flutes (all have drawn tone holes).
Recently, a customer inquired as to why he could not buy a Custom Aurumite 14k, 14k white gold, or platinum flute with drawn tone holes.  We had the chance to speak with Powell’s President, Steven Wasser, to find the answer…

Closer view of the Signature flutes.
Mr. Wasser explained that the reason why drawn tone holes were not an option for flutes made from these metals is because of the metals’ ductility.  Ductility is essentially the metal’s capacity to be drawn out into a different shape (without breaking).  If a metal has a high level of ductility, it would have the capacity to withstand the tone hole drawing process.  In this process, Wasser explains “the tubing is pulled out of a small hole in the flute body into a tall ‘chimney’ to form the tone hole.   It is then rolled over and flattened to create the surface for the pad to close against” (from the post Tone Holes - Drawn or Soldered?, May 16, 2012). 

Super close-up on drawn tone holes.
All metals have a ductility level, and both white gold and platinum have reduced ductility – therefore, they do not flow the same way a much more ductile metal like silver would.  Aurumite is comprised of two different metals – one outer layer of silver, and one inner layer of 14k gold.  Silver and gold have differing levels of ductility, and the layers will want to move at different rates (with silver wanting to move faster than gold).   Although a numeric value is not always given for a metal’s ductility, a certain level is needed for the metal to be successfully drawn into tone holes.  Wasser states that a “100% success level is needed,” so if even one tone hole does not form properly in the drawing process, drawn tone holes would not be an option for that particular metal.  In this case, it would be the Aurumite 14k, 14k white gold, and platinum.

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