 The Clarinet BBoard
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Author: john gibson
Date: 2004-02-18 23:40
I know this isn't a REAL PRIORITY,,, but I need/want to know why silver "pits" with age? I cleaned my SILVER KING (but good)....she looks great.....THEN,.,..I see "pits".....OR "holes" in the body and keys after a while of non-use. WHAT THE HECKS GOING ON? I Keep her clean. Swabbed. Wiped. No affect on play-ability...just LOOKS. SO....?
JG
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Author: Gordon (NZ)
Date: 2004-02-19 00:25
Silver plating is microscopically porous. It is generally regarded as decorative rather than protective of the base metal.
Not all silver plating is the same, especially in thickness, so some will be more susceptible to pitting that other. For example I have noted that very low quality Chinese clarinets, made decades ago, with hard rubber bodies giving off corrosive sulphur fumes, have silver plating that seems never to pit, although it readily tarnishes black.
Modern manufacture, even of professional-grade instruments, seems to be so subject to cost cutting that some of the plating is very thin indeed. It is common for it to wear through in places within a year or two.
Some people have more corrosive perspiration than others, and some clarinets are in environments where the pollutants in the air are more hostile.
If water, or an even better electrolyte such as salty perspiration, permeates an invisible pore down as far as the base metal, then we have a situation of two dissimilar metals in contact with eachother in the presence of an electrolyte. This sets up what is called a galvanic cell, much what the same as in a battery. In a galvanic cell one of the electrodes, in this case either the base metal or the plating, is 'eaten' away. At each location that this occurs, the action continues until the damage is big enough to be visible as pitting or blistering.
The process may be greatly accelerated by skimping on the chemical bath treatments before and after the plating process, leaving behind traces of strong electrolytes.
It may also be accelerated by using a base alloy that is is further displaced from silver in the 'galvanic series' indicating 'electrode potential'. There are other complicated factors involving the crystalline structure of particular alloys used.
The technical details in the way the plating is applied also affect the degree of porosity of the plating. The silver used in silver plating may also be alloyed with certain other metals, such as rhodium, which may increase resistance to attack.
The pitting may also be caused by direct chemical action of corrosive chemicals not properly dealt with during the cleaning and plating process.
But note that thoroughly handled (although regularly-washed) Electroplated Nickel Silver (EPNS) cutlery with any sort of reputation for quality does not pit. The first damage to the plating is typically wear, seemingly where the items sit against the table. These are made from essentially the same base metal and plating as plated instrument keys. One has to wonder if manufacturers of clarinets are deliberately skimping in their attention to robust silver plating.
I am no expert on this topic, and I welcome any corrections to the content of the above.
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Author: BobD
Date: 2004-02-19 13:34
You've explained it quite well Gordon. It's the pits! Even chrome plating has pits.
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Author: JMcAulay
Date: 2004-02-19 14:16
Hey, Gordon: Not bad for someone who is "no expert."
Regards,
John
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Author: John O'Janpa
Date: 2004-02-19 14:42
Gordon's explanation sounds good to me.
As someone who used to try and keep the chrome looking decent on a 1958 Buick that was driven on heavily salted roads, I think a coat of wax after cleaning may delay the pit formation. A coat of laquer would probably delay it even longer.
John
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Author: Ken Shaw ★2017
Date: 2004-02-19 15:00
Gordon -
Old Chinese klunkers have SILVER plating?????? I would have thought unplated pot metal.
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Author: Gordon (NZ)
Date: 2004-02-19 15:06
No!
The Chinese have been using silver for a long, long time. I wonder if that is longer than the Western world?
I think their plating on the clarinet keys may have been unusually thick. Perhaps silver is very cheap in China.
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Author: jim lande
Date: 2004-02-23 03:56
I have a Chinese Lark. The plastic turned green (probably long term sun exposure.) they keys are pot metal but silver plated. However, the silver plating was so thin that some places looked like they were missed altogether -- the plating just seems to fade out. And these are not wear points, but rather spots not visible until the keys were removed.
Someone on the board once suggested using clear nail polish on touch points.
I keep an anti-tarnish strip in each case and this seems to help reduce tarnish. I wonder if it reduces pitting, too.
One more thought: Some areas have sulfuric acid in the air -- or at least in the clouds. (Think acid rain.) Maybe keeping a desiccant in the case would help.
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Author: paulwl
Date: 2004-02-23 13:24
They say 90% of everything is crap. With metal clarinets the figure approaches 100% to such a degree that the exceptions (eg: Silver King, Silva-Bet, Selmer, Conn, Buescher, Haynes) serve mostly to prove the rule.
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Author: Gordon (NZ)
Date: 2004-02-23 13:41
The many Chinese Larks I have worked on did not have pot-metal keys. I often had to silver-solder them, and did so successfully. 'Pot-metal' cannot be silver soldered.
However I can say that the metal contained small pockets of slag.
In my experience the unplated areas are where metal had been removed AFTER plating, in order for the key not to bind against a spring or other part.
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Author: jim lande
Date: 2004-02-24 01:58
Gordon -- I defer to you on all aspects of the Lark. The keys didn't look well made, and seemed soft. Fortunately I did not have to solder any. I used the term pot metal too casually.
Paulwl: If one assumes that eBay is a representative sample, then the pro models probably represented more than 5% of what was sold. However, instruments owned by individuals (vs schools & store rentals) were both much more likely to be pro and much more likely to have survided to get onto eBay. Still, it is likely that a couple percent of instruments were higher quality. What percent of new clarinets today are pro?
Some metal clarinets were not well made, but I believe that the leading student models (American Standards, Cavaliers, Three Stars, etc) approached student models made today. Maybe not the best student models made today, but certainly better than the things sold in Wallmart. (Disclaimer: I have restored 4 student metal horns and 3 plastic ones. Not a large sample and I was just learning back then. Gorden: your opinion?)
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Author: Gordon (NZ)
Date: 2004-02-24 02:49
I have only ever worked on 3 metal clarinets, all junk. One was the comon 'G' clarinet made in Turkey, with pot metal keys, all hopelessly misaligned with tone holes, which were soldered on and falling off. The pads were falling out too. At least I was wise enough not to work on it; I think that was the only clarinet i ever refused to work on - very sad for its touring owner, also from Turkey.
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