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@Daniel C Oberloh

Do you know of any technology whereby the interior surface of a yellow brass tuning slide bow can be coated with a durable thin material (and one which would adherence would never fail) whereby dezinctification could be preempted?

I know of no such method/substance, but just wondering if anyone else (ie. a knowledgeable person) might.

Of course, a yellow brass bow can be replaced with a low brass or nickel brass bow, but not all manufacturers are willing/able to offer that option, and there are legion discontinued models (whereby the yellow brass bows are still quite intact but it is observed that water collects in them - both during and after playing) where a factory-made bow substitution (again: low brass or nickel brass) is not an option. A few people might be able to custom-fabricate a bow, but (surely) that would involve considerable (if not a nonstarter level of) remuneration.

Plating a bow (seemingly, an option) always plates both the inside and the outside, but that would then involve a bow being the wrong finish...and interior plating is always (due to the way that electrical current flows through a bow during plating) a "dusting" - compared to the thickness of the plating on an exterior surface.

Of course, "regular cleaning with a mild acid-based cleaner" is the simple answer, but - in the real world - that doesn't happen very often, and dezinctification happens more often.

Thanks for reading this inquiry.

Regarding plating, wouldn’t a non-conductive mask on the outside — temporary lacquer, wax, whatever — keep it from being plated when the inside gets done?

Seems like lacquer would be the most available in your shop. but I was thinking of an industrial product that alters the molecular stucture of the brass surface. Like gun blue for steel.

This also popped up:

Architectural brass is challenging to maintain due to tarnish and oxidation which dull, darken and corrode the brass. Everbrite Protective Coating and ProtectaClear seal and protect brass from tarnish and oxidation, unlike lacquer coatings that yellow or darken with age or exposure to UV, maintaining the brilliance and shine of the brass for years to come.

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ProtectaClear is used in hotels, casinos, restaurants and offices to seal and protect highly polished brass from tarnish, oxidation, corrosion and fingerprints.

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Brass elevators, architectural features, railings and brass doors can all be polished with many common polishes to maintain their shine; however this is both costly and labor-intensive. ProtectaClear keeps brass looking freshly polished and can be maintained indefinitely with very little labor effort.

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Tim Jackson wrote: ↑Sun Jun 05, 2022 6:55 am Seems like lacquer would be the most available in your shop. but I was thinking of an industrial product that alters the molecular stucture of the brass surface. Like gun blue for steel.

When you blue steel, you are in fact causing the iron molecules to oxidize. But the blueing process creates ferrous oxide rather than ferric oxide (rust). The difference is that ferric oxide, red rust, weakens the metal and keeps spreading. The ferrous oxide blue is strong, does not spread, and is protective because once the iron is oxidized in that way, it is prevented from oxidizing the other way. The copper-zinc alloy making up brass is quite different. Copper is the biggest component of brass and can form 2 different oxides. Cupric oxide is red and cuprous oxide is black, but either form is destructive to the metal. However, most people associate green with copper “oxidation”, such as is seen on the Statue of Liberty. In reality this is not oxidation but the formation of copper sulfate. Architecturally, this green patina is actually a good thing because it actually protects the metal from oxidation as well as anything. Ironically, the “green stuff” is what brass musicians fret over and want removed via chemical cleanings and such. But truth be told, if a green coating forms on the inside of our tubing, we should probably leave it alone because it’s protecting the metal from destructive oxidation. If you are looking for a copper/brass equivalent of blueing for steel, that would be it. I’d be willing to bet there’s an industrial chemical to create the green patina, probably something with sulphur in it.

Hot bluing the interior of a slide assembly is out of the question, and cold bluing (according to gun smiths I know) is temporary.

Interior lacquer would flake off - obviously causing problems.

3M Platers Tape - over the exterior of a slide - might work, but I'm still not sure how much current would flow over the interior. IF (??) it was effective, I suppose interior copper plating would work as well as anything (as a barrier against dezinctification).

Thanks for thinking about this, and working towards solutions.

Further research into this topic and I find out that “verdigris”, the “green stuff” that forms on copper, brass, and bronze, is not only copper sulfates but also could be copper chloride or copper acetate. Sulfuric acid can create it, as well as vinegar with salt, or ammonia. Even though most brass players want to avoid “green stuff” inside their horns, I still think properly applied it could be a deterrent to actual corrosion. Also, I thought of “oiled bronze” plumbing fixtures which are considered very stylish and have a sort of black-ish coating on them. Not sure how this is created. Would any sort of chemical alteration of the copper do anything to prevent de-zincification? Don’t have a clue!

I'm not much of a fan of green on the interior of a brass instrument.
My goal (and I seem to always achieve it, and - luckily for me - without any dezinctification) is for an instrument's interior surfaces to achieve a brown tarnish, and for the articulating surfaces (casings, slide tubes) to feature that type of oxidation and with the oxidation polished to a very smooth finish - via generous/every-time-an-instrument-is-played oiling and usage.

How difficult is it to build and form one-off replacement parts? I'm assuming "pretty difficult," but as our tubas get older, makers close/change/adapt, etc... I'm thinking in the near future (30 years?) we could end up with a glut of tubas with significant but fixable issues, but nobody to fix them

I really appreciated the full nickel silver valve section of my old Miraphone 188, just like @jtm has now. When I bought it from Dillon Music, Matt told me that it would pretty much last forever. And that it must have been pretty difficult to build.

Creating a truly decent (round-throughout) small bow requires using a mill to cut out two halves of a mold.
Tubing is placed in the mold, an object or high-pressure liquid is forced through the tube, and the tube is "blown out" to the shape of the mold.

Hand-making wider bows is somewhat easier, but (to end up with one that is nearly perfectly round) requires more time (at least, of mine) than someone might wish to purchase.

jtm wrote: ↑Sat Jun 04, 2022 10:06 pm Regarding plating, wouldn’t a non-conductive mask on the outside — temporary lacquer, wax, whatever — keep it from being plated when the inside gets done?

This was my first thought as well. Nickel plating on the inside. I don't know much about plating, but I do think that it's done in a tank of fluid of some sort. I wonder if it's possible to run the fluid through the crook/bow/whatever rather than submersing the item in a tank. Kinda like the way bloke likes to do chem cleans. iirc, the bufferboy method.

Even if very much plating could be coaxed into adhering itself to an interior surface, 3M Platers Tape (exterior) works pretty well, but a little bit of plating always seems to get past it, and nickel is a b!tch to remove manually.

What causes dezincification?
That is to say, would a magnesium sacrificial anode buy any time?
Maybe someone needs a side hustle selling heavy magnesium valve bottom caps along with snake oil valve & slide lubricant

Lime dissolves the zinc out of yellow brass.

tokuno wrote: ↑Mon Jun 06, 2022 9:48 am What causes dezincification?
That is to say, would a magnesium sacrificial anode buy any time?
Maybe someone needs a side hustle selling heavy magnesium valve bottom caps along with snake oil valve & slide lubricant

I clicked around on the protectaclear website. Can’t seem to find any downside. I know there always are some, but can’t find any. Poor man’s relacquer job for raw brass.