A couple clarifications...

The vast majority of saxes are not made of gold, But brass or bronze and then gold or silver plated, (Or black nickel, red, blue or whatever...<G> There are many types of brass yellow, gold, rose, but they are all brass, not gold.

Only 24K Gold is considered completely corrosion resistant.

The plating procedure is the pretty much similar whether or not you have an industrial setup for volume or a simple kit. The choice of toxic or non toxic chemicals only changes the amount of time necessary for the same amount of plating. The old method of low voltage and long exposure time will deposit a heap of metal in any situation, followed by burnishing to compress the metal and !****! tarnish by limiting air exposure on the compressed surface area.

There is non-tarnishing silver out there now. The jewelry industry uses it. It has its own mark, AS for Argentium silver which can also be heat hardened and is supposedly laser weldable. Landell is the only one I know of making flutes out of argentium silver. (just recently)

24K gold is very soft so it is not usually the choice of plating instruments, however it is the most corrosion resistant and can certainly be done without any problems. 12,14, or 18K are most likely to be used for instruments. and while their corrosion resistance varies with the amount of gold, they are still much better than silver if you have an allergy to silver.

The reason that gold plating on a flute is done is to help keep the instrument from tarnishing severely. (stylish cosmetic issues aside) From what I can tell, the makeup issue is one where the reaction seems to be deposited on the player and to the flute..It's like using tarnish shield on a flute, which turns black also. (but you can safely rub it off again, unlike removing tarnish)

Joe B

"And as Kara said, I dont want a fight."

Please tell me where and when I ever said that please? I said I do not wish to ARGUE. There is a difference.

JButky said pretty much everything for me. Thanks.

My private life and the way I see fit to do my business will remain exactly that...private.

God bless you all!
Kara

Okay....

(I don't want to continue anything that should have been put to rest, but I don't see why a discussion of gold plating should not include gold plating in relation to allergic reaction... I understand you want to keep the topic limited to 2 topics. But, I know other people who have reactions to silver and the problems with the gold plating that are being discussed here.)

I know for a fact that I am allergic to SILVER and not NICKEL. I have been tested for nickel and silver reactions and the silver is always the cause; the flute I work with and have worked with for years is finely made and the plating on it has had to be treated for me, but the silver still causes slight reactions... The gold on the flute is not thin nor porous enough to not make a difference. I thank you that you do not disagree with this absolute need for gold.

Techs are not alchemists, nor are all of them chemists, so they do the best they can to make what they term "good quality products." Of course, you get the scammers, but a good tech knows that nothing they do will last forever and repairs and replacements are a must.

Personally, and this is not an attack, I think that this is a lot of drama for something very simple. You made very valid points, Micron, but your apparent knowledge of things such as this might be going over some people's heads and losing the interest of other forum members.

Don't worry, we all seek the truth, but in a world where all things are possible and nothing is what it seems lately, what could be called the truth? What is it that we are seeking? What is it that you are trying to find to prove any of us wrong or right about this matter...

This is a little out of hand, I think... Relax everyone!

<Added>

Go Kara! :)

Micron, sorry to interrupt this highly technical discussion (seriously), with a simple and candid question:

You said "The high-electrolyte environment of the saliva that some players allow on their embouchure plates could be regarded as fairly hostile".

Well, I discovered that wetting a little bit my low lip and the chin section immediately under it, helps me in the playing, as it allows for easily correcting the position (basically by turning the instrument).

I do it with the tip of the tongue (and my own saliva).

As you know, I have just bought a new silver flute and would not like to put it at any risk, even if I had to change my playing habits.

Your assessment is valid also for sterling silver lip plate such as Yamaha YFL674 or just for a gold plated one?

Also, all the links that you were referring to in your post (the long one), do not show in my PC. I am also technical oriented and very curious. I would like to read those articles about metal electroplating and its problems. Could you please provide those links again?

Thanks a lot.

Micron,

The issue of galvanic corrossion deals with materials that are not already "fused" together as in trumpet tuning slides and the like where plating can be used to prevent the corrosion process.

From the article you posted this is made pretty clear.
http://www.engineersedge.com/galvanic_capatability.htm

"Often when design requires that dissimilar metals come in contact, the galvanic compatability is managed by finishs and plating. The finishing and plating selected facilitate the dissimilar materials being in contact and protect the base materials from corrosion." (emphasis mine)

Galvanic corrosion is also seen in piston instruments, particularly the problem with various types of monel.

I don't reference Wikipedia since it is unreliable as a reader edited work in progress...

For this to occur on two surfaces already plated, the catalyst would have to be present at the juncture of the two metals. That's not very likely. Pitting is normally caused by a piece not being clean enough during the plating procedure. Either that, or it was already there in some degree and not dealt with before plating. As such the electrical connectivity is lessened or non existant leaving the area to be protected by plating vulnerable. It will pit over time as a result...

Most of the pitting is a result of that rather than galvanic corrossion.

Joe B

Micron,

It still doesn't seem to be the cause of it for me, but I will grant you that I have to take a look at it more, (plating science, not being my forte).

I still don't see how both metals could be exposed at even a porous level since the surface area of the porous area would still see only one surface (that of the plated material).

So I will take some time to read on it a bit more and see if my basic premises hold.

I think of galvanic corrosion more with plumbing where electricity is present (common form) in the system such as a water heater...

Joe B

As is usual in discussions, everybody has a part of the truth.

I have visited the three links. If you allow me a third(?) opinion), I would say that the process of galvanic corrosion does not require the metals to be in contact.

In fact, to have this (undesired) galvanic cell, one needs two metals present, having different electrode potentials, a suitable electrolyte and a closed electric circuit between both metals. And that's it

If the metals are in contact, this contact provides the electric circuit required, but the physical contact is not mandatory.

In the case of flutes (so we come back to the main subject of this Forum), when plating the silver base with gold there would not be a potential corrosion problem, as the potential difference is said to be within the safety limit of 0,15V.

If we consider nickel, brass (components) solder etc., there could be a definite problem, as the humidity in the tube from playing breathing and small quantities of saliva is conductive, and act as the electrolyte. The metals being in contact provide the closed electrical circuit.

This can explain the deep corrosion reported by Micron.

Wiki says the different electrode potentials comes from the different speed of each metal in "dissolving" in the electrolyte. This assessment is somewhat shocking, as I did not expect the metals to "dissolve" in a simple electrolyte such as salty water or saliva!. It may be a misconception of the author. But I do not have a better theory and in any case the origin of the electrode potential is tangential to the reasoning.

I have been related in the past with companies producing and installing active cathodic protection equipment. This works by impressing a suitable DC current between the part to be protected (typically a gas pipe or oil pipe) and the surrounding terrain. The current must be high enough to make the pipe a few volts negative in reference to the ground (so as to act to the cathode in the reaction).

In some cases hundreds of Ampers are required, depending in the conductivity of the terrain.

Another interesting case of cathodic protection is completely passive, using highly reactive metals as sacrifice anodes. (such as magnesium) They are a standard in outboard motors in ships and protect the propeller and other metal parts of the engine from very fast and destructive corrosion.

It's a pity these methods cannot be used on flutes...

I would advance a rather bizarre reflection: Many (older) people have teeth amalgams, made of silver and mercury (and maybe other metals).

Could it be that we are inadvertently producing corrosion because we have the three ingredients:

- 2 different metals present
- an electrolyte (saliva)
- a closed electric circuit made by our tissues and humid skin, the more difficult the piece being played, the more humid... (j.j ...or not?)

Braces (in younger) could also be an issue...

Thank you, Micron! I understand you mean and I hope that we can keep everything okay! This turned into a bit of a philosophy course for a moment!

Micron, Did just a cursory study on some websites to be better informed...

A couple questions..

Exactly what is your beef with plating? Is it merely that galanic corrosion can exist or are you specifically blaming corrosion (pitting) on Gold/silver plating?

Most of the info I've read show Gold and silver next to each other in the Galvanic series and on the cathodic side of the chart (which is army spec for immersion in seawater).

It could be argued nonetheless, that the presence is in a harsh environment (albeit only temporarily) and still the anodic series for Gold plating is 0.

Silver plating is 00.15 with a difference therefore of the same (.15 in the anodic index) which is considered acceptable in even a harsh environment.

So I am at a loss to know exactly what the problem is. Silver and gold are right next to each other in the index, so I don't understand why there is a problem.

If you have experienced pitting, from the information I've seen so far, (limited at best) there must be another reason for that corrosion other than galvanic...

Please clarify where I am misinterpreting you.

Joe B

The difference between gold (0 v) and silver (0.15 v) is 0.15, which according to the info at the top of http://www.engineersedge.com/galvanic_capatability.htm is borderline in a harsh environment. I believe that wet areas on a flute can be regarded as harsh.

According to this website....
http://www.corrosion-doctors.org/Definitions/galvanic-series.htm

...it is acceptable, which uses the same formula. Since the standard is immersion in sea water for these tables:

http://www.eaa1000.av.org/technicl/corrosion/galvanic.htm

(The table is the galvanic series of metals in sea water from Army Missile Command Report RS-TR-67-11, "Practical Galvanic Series.")

I just don't see how that can be equated to playing a flute, Unless you are playing it underwater.

Now there will be a galvanic effect, but it would seem to be rather minimal given the standards these are based upon.

I quite frankly have not encountered the level of pitting you describe from regular plating. I have seen plating corrosion where the plating job was not done well, chemical residue and/or lack of cleanliness. Very rarely have I seen anything with Gold pit underneath and never below the surface of the strike plate unless carelessness in the cleaning process happened. In those cases the residue pitted the metal badly. But that was due to contaminants and not galvanic corrosion.

It is in my opinion that what you have witnessed is explained in detail on pg.7 of the artisan plating link you provided. This is far more likely the scenario (although it's possible it might encourage the galvanic corrosion you speak of. I have to consider that more.) The gold lattice mesh is just gold at that point not a mixture of gold and silver, so I don't know how you are making that connection with a porosity argument.

But if galvanic corrosion were the rule, this would all be a moot point since no one would attempt it. Obviously the problem is in procedure and poor plating practice rather than in the exclusive realm of galvanic corrosion. Even the porosity problem according to the artisan site points to plating practice rather than galvanic corrosion.

Sorry Micron, I'm not convinced yet, the arguments do not hold up for me since there are alternative answers to the problem that are much more likely to occur..

Joe B

<Added>

Found this also which also confirms the presence of impurities as the cause of pitting and corrosion in the manner you've witnessed:

http://www.corrosion-doctors.org/Localized/Frames.htm

OK, I re-read some pages and completed going over the full 14 pages. There is a lot of useful information, albeit it is completely related to watch gold plating.

A couple of interesting assessments I would like to recall:

In Flute plating, the conditions are quite different from watches. Corrosion, be it galvanic or not, could be more important on a flute surface. But, the following two parameters are reported to be very important:

- The thickness of the final metal layer. The site artisanplating.com recommends something over 5 microns for a durable work. Maybe on a lip plate it should be still higher, as (according to that site), increasing the thickness reduces the porosity of the gold layer.

- The composition of the gold, pure or in alloy with other more or less exotic metals. This seems to affect not only the color, but the hardness of the surface and its resistance to wear from abrasion and other factors.

In conclusion, I think that the process of gold plating could be successful and result in a durable and beautiful adornment, even if performed in small artisan workshops. As a condition, the thickness, composition of the alloy and good preparation of the surface prior to the electroplating, as well as other parameters (bath temperature, intensity of the current and probably a few others) must be fully known and taken into account by the artisan.

The fact is that we cannot say more (and we should not) about the technics used by artisans posting in our Forum (please let me call it "our").

It's true that each one runs its own business according to his/her own and best criteria and I have no doubt that, at least for people here that have shown such a keen interest in participating and helping others so much, the responsibility and the quality of their jobs must be taken for granted.

It does not exclude the fact that you technicians, will continue to see those defective works you have clearly reported so far; but let us feel assured that they are not coming from members of our Forum.

True is that I cannot prove it; it is just an assumption similar to so many others we must take everyday, to continue trusting people and enjoying the belonging to a community (even our own neighborhood), no matter it is virtual or not.

I am not directly suggesting that this deep (and extensive) discussion should end here; but I it is my opinion that the subject has been so fully discussed that it already may be boring or even annoying to other members.

For this reason, I tried to float these simple conclusions as an elegant way out, should you accept it.

If it is not the case, the subject is so interesting and complex that a full agreement is difficult that we could see posts and technical references for still a long time...

Jose, it's OK, that what happens when Micron and I get going, We eat this stuff up. When some of us techs get into the same playground we find our own set of swings and monopolize it!

I've known Micron quite a while (Electronically). As is the case here, we often find ourselves in more agreement than disagreement.

It just takes a while to get there, and thanks to Micron for pushing my investigational button to get me started.

Joe B

Then suggest just one reason, why a microscopic blemish, invisible to the naked eye can progress to be a hole in the base metal, perhaps 0.2 mm deep within a few years, with no evidence during this time that the plating is actually separating from the substrate? I have certainly seen this on silver plated instruments. From the galvanic series it is clear that with gold involved, it can happen even more readily, as reported by technicians and players in a forum.

Well if there is chemical residue left there, trapped from the process (which could be held there by a microscopic pit) it certainly would cause the problem you are seeing, But then again, it would further pit if not dealt with anyway. (plating aside)

I just don't know whether the galvanic effect is increasing the reaction.

Micron, even the equipment out today is pretty good if you use proper methodology, It doesn't require an expert, but it does require the expert's training and knowledge (which is readily available.

I've done my fair share of cosmetic plating and refinishing and the equipment I am using now is by far the most idiot proof and simple stuff to use. (because it was designed by an expert). As you and I agree, it is the procedure involved. The equipment is inexpensive and quite good now for small shops.

Joe B

The report on the amalgam effects on body tissues and systems is really scaring. With those 27 scientific references quoted I suppose it is a serious source.

I had posted the idea of galvanic effects between those dental amalgams and the flute metals as my own speculation; I had no read that before.

An inspiring source for my idea was my last visit to dentist; I was recommended to replace all my metal amalgams (I had quite a few) by new polymer fillings. The doctor would not elaborate on the deep reasons (apart from the obvious hefty bill) behind his recommendation.

Although I trust less those organic polymers in my mouth that the old faithful silver-mercury thing, I agreed. Intuition, again.

Perhaps I have more exo-estrogens in my body now, but my flute might corrode less, who knows!

it is my opinion that the subject has been so fully discussed that it already may be boring or even annoying to other members.

I would hope a vaild discussion wouldn't be stopped because some people might be getting bored or annoyed over it. I have been keeping an active eye on this thread, although I have not had time to read all of the links involved. I won't say I have any clue on this topic from a personal standpoint, however I have throughly enjoyed reading the technical sides of this discussion. Just because some of us are no longer commenting, does not mean we don't enjoy the discussion, or that we are not learning from it.