 The Clarinet BBoard
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Author: Maarten
Date: 2004-04-21 10:50
Hello all
I am wondering if anyone has experience with bronze disease in a clarinet. It is described e.g. here:
http://nautarch.tamu.edu/class/anth605/File12.htm
http://www.hfmgv.org/explore/artifacts/brass.asp
It basically is a corrosion process that can happen to cupper alloys (that includes german silver) and that might eat away all metal if left alone. The keywork on my Selmer CT seems to be suffering from this as there are green spots on it that I can easily wipe of, but that will return in a couple of weeks. It is most prominent in the thumb hole at the backside of the upper joint, but it is also visible in other parts of the keywork that I often touch. It seems it is eating away the material (very slowly though) .
First, does anyone have another explanation for the green stuff piling up?
Second, if it is bronze disease, could anyone recommend a procedure to remove it? There are some suggestions on the websites I linked, but they are rather harsh and I would need to remove all metal from the wood (Can the metal thumbhole be removed at all?).
As a related queston, most of the keywork has a patina on it that numismatists would like, but that most clarinetists frown upon. Does anyone know of good methods to clean the oxidation layer off? Polishing with a soft rag seems to help, but only after very long and hard work. Some numismatics sites suggest to put coins in citric acid to clean them. Does anyone have experience with that?
Thanks for any answers,
Maarten
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Author: Synonymous Botch
Date: 2004-04-21 11:40
The Cuprous alloy you describe is my favorite material for clainet keys.
To properly polish these, disassembly is required.
Any decent polish will leave residue (somewhere) that will cause a problem at the least opportune moment.
There are detractors, to be sure, but I like 'FLitz' as recommended by Caswell plating company with a soft cotton rag.
Patience, and a few Q-tip cotton swabs will get the keys shining bright.
I find that Flitz keeps down the degree of corrosive wear on touch spots.
If your thumb hole is worn, it can be replaced by a qualified tech.
********
The sort of verdigris you describe is also common to insturments stored in a humid environtment... is the case old, too?
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Author: BobD
Date: 2004-04-21 12:05
It would appear that your problem is caused by the salt in your perspiration. It also sounds like the plating is worn away from some keys in some areas. I assume the keys are plated but it's possible they are not. Try washing your hands prior to playing and periodically drying the perspiration with your handkerchief. Also, wipe the keys after playing.
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Author: Maarten
Date: 2004-04-21 12:27
Thanks for the quick responses
Synonymous Botch:
thanks for the suggestions. I still have the original case, so, indeed, it is quite old. The climate in the Netherlands is quite humid as well, so that could fit.
BobD:
Indeed I don't think the keys are plated at all (any more?), as all keys show a greyish tarnish. Would you recommend having them plated again (after they are cleaned)? My technician has never said anything about that, although I have also never talked specifically about this with him.
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Author: John Morton
Date: 2004-04-21 15:40
I second BobD's suggestion to wipe the keys down after playing. I have a number of nickel plated (stringed) instruments which can be very difficult to restore if I don't peek in the cases once in awhile to look for tarnish. Certain players find that a greenish patina develops so fast that they can't keep up.
In machine shops there is a remarkable effect which is easily seen on freshly cut mild steel surfaces: an immediate rusting of the surface where the fingers of certain individuals have touched it. It turns out that some people have such acid skin chemistry that you can discern the fingerprint pattern in rust, within a day after the piece was handled. Some say that heavy smokers are prone to this condition.
Bach makes "polishing gloves" for trumpet players, made of cotton and impregnated with a mild metal polish. You just put them on and fondle your instrument. But most important is simply to remove the perspiration.
John Morton
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Author: Don Berger
Date: 2004-04-21 16:40
Excellent advice John M et al. I also have wondered about the chemical composition of the green patina-corrosion product found on copper and its alloys [our common nickel {German} silver is generally at least 50% Cu]. Many [complex?] compounds of Cu exhibit this coloration, our local F L Wright's cantilevered, pentagonal-designed "tower" uses this patina for exterior decoration !! Will have to ask [again]. The graying is likely due to mild Cu sulfides formation, Cu and Ag are similar chemically. Comments? , please . Don
Thanx, Mark, Don
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Author: ron b
Date: 2004-04-21 16:42
In addition to previous comments, Maarten, if I may, this sound somewhat like a brass instrument condition called "red rot", where copper begins to separate from its alloyed metals, tin, zinc, whatever they happen to be. It usually happens to leadpipes and crooks but can, and does, show up elsewhere :( Cleaning (dipping) in a 50/50 water-vinegar solution (half hour to an hour or so) will remove the green stuff and leave it smelling nice. I don't know of anything that will completely stop the process. Brass horns usually need the problem section replaced. The grayish patina you describe is common to nickel-silver and, as far as I know, will not cause any serious deterioration during an 'average' person's lifetime.
I also find Flitz, as Synonymous suggests, pretty good for polishing 'silver' keys. I doubt that your instrument's keys were ever plated - there would still be some of it somewhere if they were - so why go to that bother(?)... and expense :\
- r![[cool]](http://test.woodwind.org/clarinet/BBoard/smileys/cool.gif) n b -
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Author: mw
Date: 2004-04-21 16:45
It has been (arguably) stated that upon buffing old German Silver keywork - that the "tarnish or discoloration" will return within a period of time.
Of course, some say that the choice of buffing compounds can affect this "return". The "green" spots I have seen is what I would refer to as an advanced degree or state of tarnish.
FLITZ is an excellent polishing compound. Besides the obvious use of Flitz with metals, Flitz also does a marvelous job with fiberglass & hard rubber - yes, mouthpieces that you want to shine. I don't want to get into a discussion of ingestion of chemicals - as always be very careful - for some that means "don't try this at home". mw
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Author: ron b
Date: 2004-04-21 23:43
If I may throw in a little afterthought...
Some months ago, nearly a year now, I buffed and clear-lacquered the nickel silver, non-plated, keys of a clarinet. I waited about week, maybe a little more, for the lacquer to thoroughly dry (cure) before heating the lacquered keys to re-pad the instrument. The keys are as bright and shiny today as they were several months ago.
- ron b -
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Author: JMcAulay
Date: 2004-04-22 00:31
"Brasso" does a marvelous job of polishing anything with a reasonable copper and/or nickel content. On nickel silver keys, it is a wonder. It does leave a somewhat volatile residue, which is protective, but I wash it off. Keys should be *removed* before polishing, as I have no idea what the stuff would do to wood.
I have never lacquered nuckel silver keys for protection, but that sounds good to me.
Do NOT use Brasso on silver or silver plated keys.
Regards,
John
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Author: Gordon (NZ)
Date: 2004-04-22 01:34
It seems from my experience that machine buffing, if it is NOT followed by ultrasonic or aggressive solvent cleaning, leaves wax from the buffing compound in the microscopic pores, which resists the accumulation of electrolyte and acid in these cavities, hence slowing the further development of verdigris.
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Author: Maarten
Date: 2004-04-22 11:31
Thanks everyone,
it seems most here have experience with the normal tarnish, but not bronze disease. The advise given by all of you on how to treat the metal and how to polish it is very usefull to me. I will certainly use it to get the clarinet back to splendour.
ron b, I have also read something about red rot and it seems indeed related to what I describe, although I believe it is not the same. Do you know of any links or other resources where this is described? Also, does anyone know if (leather and cork) pads suffer from a treatment with vinegar?
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Author: BobD
Date: 2004-04-22 14:57
Unplated german silver keywork is difficult to polish decently as compared to nickel plated keywork.....period. The polish and lacquer treatment sounds good to me for someone who likes to keep GS decent looking. Regarding your metallurgical questions you will find much misinformation on these subjects. Since they are not involved with your situation have fun searching but don't believe everything you read.
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Author: ron b
Date: 2004-04-22 22:31
Maarten -
I don't know right off where you'd need to search for 'red rot' information. I learned about it during a repair (class) training session. It may be a term used by some repair techs and not standard terminology - I don't know. The reason I brought it up is that it seems to be Related to, although probably not truly the same as, your situation. I though it worth mentioning, however, since both conditions seem to involve separation of alloyed metals.
Bob's cautionary remarks are true for any 'Net info; there's a lot of junk floating around out there. If we knew how to reverse the process, maybe turning lead into gold while we're at it, we could simply buy new horns for everyone... 
- ron b -
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Author: Maarten
Date: 2004-04-23 07:59
I certainly agree that a lot of information 'out there' is not trustworthy; most of the sites I found about bronze disease are by amateur numismatists, which is why I asked for an opinion on this board. I have been reading here for quite some time and I value the opinions here. As none of you have seemingly ever had bronze disease, or even heard of it, I will take it that that is not what I have on my keywork and clean it off with more conventional methods.
Thanks again to everyone
Maarten
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