Nickel Silver Ferrules are considered by many rod makers to be the best type of ferrules to use on Bamboo Fly Rods. They are certainly more traditional than the new and lighter weight Titanium ferrules. First known in China, the alloy now known as Nickel Silver came west in imported goods. In the late 18th century, a German metal works company produced a similar alloy. About 50 years later, Germany held a competition to develop an alloy most able to imitate sterling silver.
Nickel Silver, also known as German Silver or German Nickel Silver, actually contains no silver at all. It is an alloy normally composed of Copper (Cu), Nickel (Ni), and Zinc (Zn). The GSA has an informative technical description of Nickel Silver which you can find at www.gsa.gov/portal/content/113754 if you are interested.
Nickel Silver’s component elements can appear in the alloy in the following possible percentages: Copper; 50%-80%, Copper; 50%-80%, Zinc; 10%-35%. Of course, the combination can’t exceed 100% and the resulting alloy has differing characteristics depending on the percentage of the mix. Nickel Silver is often prefaced with a percent (12%, 18%, etc.). This percent is reflective of the percent of Nickel contained in the Alloy. One example of 18% Nickel Silver is 65% Cu, 18% Ni, 17% Zn.
A note, Nickel Silver will develop a protective oxide or patina when exposed to oxygen; the patina is brownish-green when exposed to oxygen for a long period of time. The zinc content of Nickel Silver makes the alloy sensitive to acid and sulfur pollutants and can cause the ferrules to tarnish. The alloy’s high copper content makes the ferrules very sensitive to chromic and nitric acids. Be sure that your bamboo fly rod (and attached components such as nickel silver ferrules, nickel silver agate stripping guides, etc.) is clean and dry when you place it back into the rod tube. Another note is that some people are allergic to Nickel; however, since Nickel Silver Ferrules and Stripping Guides are on Bamboo Rods, not worn as jewelry, there should be almost no prolonged skin contact.
Nickel Silver Ferrules are sized in 64ths of an inch; this sizing is based on the inside diameter of that part of the ferrule that is to be affixed to the bamboo fly rod. The male ferrule of the Nickel Silver Ferrule set must then be lapped to fit the inside of the female ferrule. This must be done carefully, because the difference between a correctly fitted ferrule set and a ruined ferrule set has been described as the “thickness of smoke”. However, when fitted correctly, the ferrules mate snugly and make a characteristic “pop” when separated.