Corrosion silver vs lacquer

[Brassedoff971]

I was keen to know if silver plated instruments corrode less then lacqaur ones? Such as red rot ect...

I know corrosion starts from the inside so if an instrument is plated, does that mean the plating on the inside of the tubing will protect the brass. Or will it still happen if the metal quality is low such as Chinese made instruments.

[peterbas]

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[gocsick]

So red rot is actually really interesting from a metallurgical perspective. When I get some time this weekend... I will write up a longer post on it.. along with dinner situations about how improper hear management during repair can accelerated it.

Specifically to the original post.... Chinese instruments are not going to be any more susceptible to red rot than European instruments... they are probably getting their sheet brass from the same places.. The concentration of Zn in the metal and the presence a wet acidic environment for a LONG time are the main factors.

[kingrob76]

There is no silver plating on the inside. You can see that inside the bell where you can see that only the upper part is plated.
It is mostly a cosmetic thing.

I'm not looking at it directly at this second, and won't be able to for a bit, but I'm fairly certain my Eastman is silver plated both inside and outside - I suspect the production time saved is more cost effective than the cost of the silver. I know the inside of the bell is fully silver plate all the way down through the bottom bow as well as the inside of several tuning slides, but I'll run a camera up through it at some point just to be sure.

[Pauvog1]

Plating has no effect on red rot. Red rot typically occurs internally in non-plated areas.

Some horns have nickle silver or red/gold brass parts (such as lead pipes or etc) that in many cases are more resistant to red rot, but again that is more about metal alloy, not plating.

[bloke]

Often, when dezincification occurs with silver plated instruments, the silver plating (in the rotted spots/areas) will de-bond and form a "bubble".

Regular cleaning, soaking the interior areas (certainly capillary portions - ie. valve sections) with mild/safe/recommended acidic solutions, and generous (regular...me? Every time I play) oiling discourages the formation of scale on the interiors of instruments.

People are sick-and-tired (particularly those who make-and-market expensive *"valve oils") of me pointing this out, but (so-called) "ultrapure lamp oil" is only pennies per ounce (if bought in gallon jugs) and - in this price range, and when transferred to empty valve oil bottles - it can be applied more-than-daily (and generously) to valve section interiors... (Lime deposits don't form very effectively at all on oily surfaces, which is why - when touring underground caves - tourists are told to refrain from touching ceilings, as even skin oils will discourage the formation of new limestone stalactites.)

...Even my 4th valve slides and 5th valve slide "loop-the-loops" interiors (when I pull them and inspect them) are consistently oily and (yup) free of hard scale. Otherwise, the "slime" stuff (nasty "slime" as opposed to hard lime) needs to be removed periodically, but my instruments never show evidence of interior hard lime scale.
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*Some makers/marketers/sellers of "high tech" valve oils claims of "staying power" do not interest me in the least, particularly not at $6+/oz. What I'm interested in is an oil that's thin enough and inexpensive enough to routinely (ie. daily-or-more-often) coat the interiors of my instruments' valve sections so generously with oil that - well - the blah-blah-blah prevention (discussed above) occurs.

[Snake Charmer]

A thick silver plating won't stop the red rot of the brass below but can keep the the horn intact for some time. My Courtois French C tuba , made in 1940 suffers from red rot. The leadpipe cracked open now which would be easy to replace but there are also blisters on some of the conical bows so I think it is beyond repair now. At least it still looks shiny.
I don't blame it for the brass quality, this tuba was made in Paris during the German occupation for the front theater in Lille, where it was played by french musicians for entertaining the German troops. And with all troubles of material shortages during the war it seems to be a factory-made frankenhorn, put together using older parts and ingenuity

[bloke]

A thick silver plating won't stop the red rot of the brass below but can keep the the horn intact for some time. My Courtois French C tuba , made in 1940 suffers from red rot. The leadpipe cracked open now which would be easy to replace but there are also blisters on some of the conical bows so I think it is beyond repair now. At least it still looks shiny.
I don't blame it for the brass quality, this tuba was made in Paris during the German occupation for the front theater in Lille, where it was played by french musicians for entertaining the German troops. And with all troubles of material shortages during the war it seems to be a factory-made frankenhorn, put together using older parts and ingenuity

I wouldn't necessarily blame it on that.
Different users leave more-vs.-less lime inside instruments after playing them, and different uses vary their cleaning routines from "none" to "meticulous".

[MikeS]

People are sick-and-tired (particularly those who make-and-market expensive *"valve oils") of me pointing this out, but (so-called) "ultrapure lamp oil" is only pennies per ounce (if bought in gallon jugs) and - in this price range, and when transferred to empty valve oil bottles - it can be applied more-than-daily (and generously) to valve section interiors... (Lime deposits don't form very effectively at all on oily surfaces, which is why - when touring underground caves - tourists are told to refrain from touching ceilings, as even skin oils will discourage the formation of new limestone stalactites.)

I confess to seeing this suggestion many times and only now finding myself with a procedural question. Say you have arrived at a gig and unpacked your instrument. You now squirt a “generous” amount of oil down the leadpipe. What do you do with it when it arrives at the spit valve? I’m assuming you are not leaving a puddle of oil on the stage floor. Is a generous amount more than, say, four or five paper towels can absorb? Do you decant it into a container and use it for actual lamps back at Blokeplace? Enquiring minds, or at least one mind, want(s) to know.

[bloke]

yeah...I have a hand towel (washable, not disposable) on hand.

The oily rag (being a thin oil with high evaporative qualities, and also being an oil which doesn't harm finishes) just ends up being tossed in the case next to the instrument.

It's very little trouble/expense as a red-rot preventive (as well as - obviously - a valve-wear preventative)

A gallon costs about the same as 6 ounces of some of these hotsy-totsy "valve oils".

[peterbas]

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[bloke]

Electroplating (as I've been told) is far more attracted to exterior services than (particular not) "way up in there" interior surfaces...even if the plating solution finds it way to those isolated surfaces.

Moreover, those who do it have told me (and I've witnessed) that it is particularly attracted to the polar ends of things (which is logical) and (again) exteriors of things.

This is why a worn piston (nor a new one) cannot (simply) be plated to a size. Plating will build up on a piston in an "hourglass" shape, rather than cylindrical. ie. Electroplating doesn't not behave like the results of an expert painter painting, and nor like a layer of even-thickness insulation.

Having observed diverse interior-coated things (over my several decades) which are non-metallic interior coatings, a bunch of them seem to be (at least, as far as "after quite a few decades" is concerned) somewhat temporary, and many seem to - eventually - un-adhere. Also (yes?), most of these types of things seem to coat more thickly than electroplating (ie. "considerably thicker than negligible thickness").

[peterbas]

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[bloke]

People are pretty superstitious about materials.
I've been pretty redundant in this thread, but nickel brass really doesn't rot, and I've really never seen 80% copper Brass rot, and I'm also never seen 100% copper rot. Those are pretty easy solutions, because they can all be lead soldered. Rather than a coating on the interior - which is really tricky, and might not adhere forever, maybe some fully synthetic (solid) tubing would be another solution versus a challenging interior coating, but then you get into gluing or a screwing and possible breakage, and all those sorts of things, whereas nickel brass and high copper brass already solve the problem.

When I purchased my model 98, there were a few places where there was some red rot, and I simply replaced those parts with high copper brass parts. Wade did some of the same things with a 186, except he chose nickel brass.

[peterbas]

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[bloke]

Dezincification also happens in brass pipe fittings because they use the brass with high zinc content because it is easier machinable.
Sort of surprised that your 98 had some red rot but my 91 also has some spots in the silver plating and some connections that aren't soldered as good as to be expected.
But the German quality has been on demise for some years now, certainly in the car industry.
That said, having owned 5 Toyotas (made in Europe) their quality starts slipping a bit also.

Ancient Miraphone mouthpipes, main slide connector crooks and even rotor casings (knuckles) are up in the attic here that are horribly rotten. It's not something new nor Miraphone nor European nor American, and high zinc brass has always been susceptible to rotting, particularly if it's not regularly scrubbed with a brush preferably a brush dipped in a mild acid) or (again) kept oily on the inside so that lime-scale has difficulty adhering to it. Yellow brass instruments with heavy lime deposits - yet no rot showing any rot - are typically ones that are thicker, whereas the rot hasn't yet made it to the surface.

The person from whom I bought the 98 is probably a fairly wealthy person - based on their occupation, and I believe primarily a euphonium player and secondarily an E-flat tuba player. I have heard that they are a fine player, though not someone who really plays for remuneration. This instrument is one that they ended up not playing as much as they had expected they would, and it probably got played for thirty minutes or an hour or so every once in awhile, (I would wager) not oiled, and then set back down and left moist on the inside.

The fourth circuit on this instrument is almost unique in that it's all off to the side and none of it is in the back. I guess one could compare it to the so-called "new style" King tuba, which sticks all of the 4th circuit stuff off to the side. The fact that the fourth circuit tubing is all up and down defines that it collects water, and any place that collects water without the owner of an instrument emptying out the water and (again) also (as do I) really excessively oiling the interior of the valve section is subject to rotting out the zinc...
...so (again) all but one of the model 98 circuit bows are the same as the model 88 main slide bow (basically, repurposed from the model 88) so it was easy to order those in high copper brass (likely 80:20) and that's what I did to easily rid the 4th circuit of red rot.

Acid really doesn't rot brass - in my experience / observation, but it does do a really good job of corroding the surface of it (and ruining the adherance of lacquer or plating). If you have some failed silver plating where the silver plating is hiding solder joint acid bleeds, I can believe that, but I suspect that - at those spots - the brass is still pretty much intact. What I'm suggesting is that both solder acid left behind and red rot can cause plating or lacquer to fail to adhere.

All of this is from experience, and not from a book, so it is what it is. The only footnotes I can offer are "bloke believes that..."