gold plating

[heinzgries]

Last week i have bought a galvanic plating kit. Now i go on plating all my mouthpieces with gold. Its realy easy and
makes much fun. The price for the kit pay off if i plated 7 mouthpieces.
https://www.real-gold.de/en/produkte/ga ... lating-kit

[Neo Bri]

I will be curious to see how the plating holds up under playing conditions. I hope you'll keep us updated with progress and pictures.

[Driswood]

It's my understanding you need a layer of silver plate on a brass mouthpiece for the gold to adhere to. Is that correct?

[dukesboneman]

Yes , the mouthpiece must be silver plated 1st before applying the Gold Plating

[BGuttman]

There needs to be a barrier layer between gold and brass. Otherwise, the gold will diffuse into the brass and "disappear". I had this happen with a rhodium plate on a mouthpiece. It took a couple of decades, but now the mouthpiece looks like it was never plated (except for a couple of whitish wisps on corners).

Barrier layers can be silver or nickel. Silver is preferred on brass because it is closer in hardness to the brass and thus will not tend to flake.

You need a significant barrier layer to work. The normal silver plating thickness is usually good enough. Generally 100 microinches (2.5 micron).

[heinzgries]

Yes, the mouthpiece must first silver plated. I have plated 7 mouthpieces with different timbre of gold. From yellow to deep rosegold timbre. Also my Helmut Voigt alto trombone. The bell in a light redish gold. The rest of the instrument in silver. Over the silver i have plated Palladium, so their is no oxidation. If i have time, i will post some pics.

[SwissTbone]

Yes, the mouthpiece must first silver plated. I have plated 7 mouthpieces with different timbre of gold. From yellow to deep rosegold timbre. Also my Helmut Voigt alto trombone. The bell in a light redish gold. The rest of the instrument in silver. Over the silver i have plated Palladium, so their is no oxidation. If i have time, i will post some pics.

That would be interesting! I'd also be interested in knowing how the plating resists over time.

[Doug Elliott]

Many platers will automatically put nickel under gold, but that is the worst thing you can do to a mouthpiece.

[SwissTbone]

Many platers will automatically put nickel under gold, but that is the worst thing you can do to a mouthpiece.

Why?

[Doug Elliott]

Which why?
Why they do it - it's very shiny and looks good.
Why you shouldn't do it - most people become sensitive to nickel so when the gold wears off you're in trouble. Also it's very difficult to remove the nickel if you want to get rid of it and do it right with silver.

[SwissTbone]

Which why?
Why they do it - it's very shiny and looks good.
Why you shouldn't do it - most people become sensitive to nickel so when the gold wears off you're in trouble. Also it's very difficult to remove the nickel if you want to get rid of it and do it right with silver.

Thanks for both responses
So what's the right way of doing it?

[WGWTR180]

Which why?
Why they do it - it's very shiny and looks good.
Why you shouldn't do it - most people become sensitive to nickel so when the gold wears off you're in trouble. Also it's very difficult to remove the nickel if you want to get rid of it and do it right with silver.

Thanks for both responses
So what's the right way of doing it?

Silver plating first. Gold second if I'm reading Doug's post correctly.

[heinzgries]

correct. But first you must polish the mouthpiece to a high gloss and degrease it.
The shine does not come from the gold plating, but from the properties of the substrate. If this is mat, the gold plating will also look mat.

[SwissTbone]

correct

Heinz, can you control how thick the plating is becomes with this method?

[heinzgries]

not realy. This is only measurable with x-ray technology.if a closed layer is optically created, I go 1-2 more times over the mouthpiece with the gold electrolyte

[BGuttman]

Heinz is probably using a procedure called "brush plating" which is a way to touch up spots of bad plating. You don't have as much control over the thickness, which is a function of the amperage, voltage, and time which in turn becomes a function of the geometry of the part to be plated. What Doug uses (and what is normally done to mouthpieces) is tank plating where the mouthpiece is submerged in a solution and the voltage and amperage is carefully controlled to compensate for the geometry. Tank plating also results in a brighter and more uniform coating.

As to silver versus nickel as the barrier layer: I mentioned above that nickel is a relatively stiff plating, put on a soft brass underlayer with a soft gold coat above. The mouthpiece is subject to vibration, which can exacerbate the differences in hardness between brass and nickel resulting in flaking and adhesion failure between nickel and gold. Silver is closer in hardness to brass and gold and provides a better barrier layer.

[heinzgries]

Bruce is right.
I can also make a little tank plating, if i put the kathode on the mouthpiece and dip it into a small cup with goldelelektrolyd. Then dip the anode into the cup beside the mouthpiece. 5-6 V and let it in for a few minutes.

[Crazy4Tbone86]

It is my understanding that every plating alloy has a very specific voltage at which it plates and bonds best with the brass or plating layer that is beneath it. I don't believe the voltage is the same for nickel, silver and gold plating. Exact voltage control for each alloy is not achieved by many people who do brush plating. This is one of the reasons that brush plating does not last long for many do-it-yourself folks. Another reason that plating does not hold is lack of proper preparation and degreasing of the metals.

[BGuttman]

Absolutely right, Brian. The proper voltage for each metal is different (although not different for each substrate -- adhesion is a function of surface preparation. Some metals require a rough surface to adhere and others work on a smooth surface.). If the voltage is too low, nothing plates. If the voltage is too high, a very rough coating results. And the regulation has to be within 1/10 of a volt.

There is quite a science to plating, which is why there are places that specialize in that process, such as Anderson Plating. In my history of Printed Circuit Board manufacture, I had to be familiar with plating of copper, nickel (our barrier layer for gold contacts), and gold. Each plating line consisted of several baths (cleaners, etchers, low concentration high voltage "strike" plate, and full plate). And lots of analysis to keep the baths working in proper order.

Also, there are limits to what can be plated. Only some alloys can be plated, and not all metals. Some materials need to be applied using some other form, like flame coating. Also, the economics of tank plating limit the ability to plate any metal. Some metals use extremely toxic solutions (like gold), some metals use solutions severely regulated by pollution regulations (like chromium).

[heinzgries]

This is one of the reasons that brush plating does not last long for many do-it-yourself folks. Another reason that plating does not hold is lack of proper preparation and degreasing of the metals.

that may be true for many hobbyists, but i'm very thorough. I polish the surface to a high shine with a polishing machine. Then it is thoroughly degreased. During work I wear disposable gloves that are often changed. The 25 A power supply is adjustable between 2.5 and 15 V. For example, silver needs max. 3 V, gold between 5.5 and 7.5 V. For each electrolyte there is its own cup and its own brush. I also use different electrodes. For silver stainless steel, for gold graphite.
The optical results are great. The shelf life will only become apparent over time.

[heinzgries]

here are two pics from my plating session. The first, Helmut Voigt alto, bell rosegold plated, tuning slide in gold and the rest in silver. The second pic, mouthpiece rosegold, rim gold.

[harrisonreed]

Looks good! Nice left handed Alto!

The counter weight looks like it would get in the way of my neck, but it looks unique and cool!

[heinzgries]

Looks good! Nice left handed Alto!

The counter weight looks like it would get in the way of my neck, but it looks unique and cool!

its a bit behind the neck. There is enough room. And my neck is not small

[jbeatenbough]

Any update on how the plating is holding up?

[heinzgries]

Any update on how the plating is holding up?

to this day everything still looks great