Showing posts with label alloy. Show all posts
Showing posts with label alloy. Show all posts

Thursday, April 16, 2015

The Missing Ingredient in Nickel Silver

Powell Sonaré 601 (with silver-plated nickel silver keys).

By Steven A. Wasser
President, Verne Q. Powell Flutes, Inc.

Do you know the silver content of nickel silver?  If you guessed anything more than 0%, you are misinformed.  Although the name is clearly intended to make you believe that this is some kind of silver alloy, the fact is that nickel silver is comprised primarily of copper and nickel. 

Here is how this apparently came about.  An alloy of copper and nickel was developed in China, perhaps in the mid sixteenth century.  It was called paktong.  Europeans wished to copy this alloy, which had the appearance of silver, and finally succeeded in the late 18th and early 19th centuries.  Since the European metallurgy was developed in Germany, this silvery-looking alloy was called German silver.  Subsequently, because of its silvery look, it also became known as nickel silver.

Musical instruments can generally be made of nickel silver in 2 situations: where the nickel silver substitutes for sterling silver because it is cheaper, or where it substitutes for brass because nickel silver is harder.  Thus, you will find nickel silver flutes, saxophones, and French horns. Because nickel silver is relatively easy to shape and solder, you will also find instrument keys made of nickel silver, such as for clarinets, flutes, and saxophones. 

Even though nickel silver might initially look like silver, it tarnishes easily.  In addition, many people have allergies to nickel, so nickel silver used for musical instruments must be coated with something to protect the musician.  The normal coating is silver plating. 

Although silver plating looks nice and shiny at the start, it will eventually tarnish, just like sterling silver.  While the plating can be polished clean, dent removal and other work that requires manipulation or abrasion of the surface will remove the plated layer of silver.  In addition, constant daily use can wear off silver plating. 

At Powell we use only sterling silver or gold alloys for the precious metal flutes we make at our Boston area workshop.  For our Powell Sonaré flutes, we make the bodies and headjoints of sterling silver or nickel silver.  Our Asian key assembler uses nickel silver keys plated with silver to keep costs down.

In 2013, as the price of precious metals skyrocketed, we began to search for alternatives to sterling silver for flute and piccolo keys.  We looked at nickel silver but preferred a strong, clean alloy that did not require plating.  Our answer was stainless steel which, as the name correctly implies, is “stainless” or tarnish resistant, and is also strong.  (Some of the same properties which make stainless steel strong also make it difficult to form.  This required us to develop special machining and brazing technology.)  The strength of stainless steel assures the flute or piccolo player that their keys will stay in adjustment longer than instruments with nickel silver or sterling silver keys.

In 2013 Powell introduced the Sonaré piccolo with a stainless steel mechanism.  We designed the instrument with the nature of stainless steel in mind, using an art deco style that allowed us to machine the parts.  Now, 2 years later, we are introducing another version of the Sonaré piccolo which will use stainless steel keys, but with a more traditional, circular design aesthetic.  

Wednesday, April 30, 2014

What Color Is White Gold?

By Steven Wasser
President, Verne Q. Powell Flutes, Inc.

We all know the answer to the question, “What color was George Washington’s white horse?”  The answer to the question, “What color is white gold?” is not as obvious.  If you look at white gold from a distance it does appear silvery in color, but if you place it side by side against silver, you will see a yellowish tint to it.

Powell 14k White Gold with 14k Rose Gold Keys
Some jewelry is advertised as white gold, but is really yellow gold which has been plated with rhodium or platinum.  In this case the whiter tones of the plating give the impression of white gold even though the underlying material is actually yellow gold.

The 14k white gold alloy Powell uses is comprised first and foremost of 58.4% gold, calculated as 14÷24.  The balance of the gold alloy can be anything else.  Our alloy contains copper, nickel, and silver, with the latter two metals contributing to the “white” color of the gold alloy.  According to the Metals Handbook: Ninth Edition, Verne Powell’s comment about the hardness of white gold and the difficulty of working it was right on target.  “White golds work harden faster and are harder after annealing than gold-silver-copper-based yellow golds.”

Powell uses 14k white gold for flute tubing.  In limited applications we also substitute 10k white gold mechanism tubing for sterling silver where extra hardness and strength is desired to keep the flute keys well adjusted.

The same characteristics that make white gold hard and difficult to work also produce flutes that are especially resonant.
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*Gallery - Photos below show a Powell Custom 14k white gold with 14k rose gold keys (photos on left) next to a Powell Custom silver with silver keys (photos on right).