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Looks like rust, but it is only on the top of the pins. Maybe some electrolytic action. Piano has an LX

[img]https://www.dropbox.com/s/iesttil3dt3idyw/weirdrust.jpg?dl=0[/img]

Wow that's fascinating. Excuse my ignorance, but what's an LX?

As you suggest, it certainly looks like an electrolytic reaction. Unless the brown flakes on the pins are not ferrous oxide at all, but flakes of some kind of decomposing laquer that had been experimentally used to coat the tops of the pins? But that seems highly unlikely. The strings are spotless too. How very odd! What age and brand is the piano?

Disclaimer: I'm writing as a professional chemist, not piano technician.

To my chemist's eye, this shiny, globular corrosion has all the trappings of acid-induced rust. Some substance was applied specifically to the top part of the pins - the first two hunches that come to my mind would be
1) an attempt to chemically blue the pins (as opposed to applying bluing dye), or
2) an attempt at removing previously applied chemical bluing (which would typically require some form of acid).

I am surprised to see the coils and lower parts of the pins in such good shape. Whatever was applied, it must have been done with quite some care.

I haven't used these tuning pin / coil cleaners, but if they are somewhat abrasive, I think that spinning them (dry, for starters) on the pins could restore the pins to a passable state.
(credit: Schaff Piano Supply Co.)

Why is it so? The pins have superoxid but strings have not it's. Amazzing

Is that a crack in the plate near one of the tuning pins?

Mark, is there something that would corrode blued steel, but not piano wire? Maybe a polish someone decided to use?

Thanks for the replies. David, the LX is a player system, thus possibly a source of current.

The piano is an 1898 Chickering with a new block. Strings are Paulello, pins are Fly brand.

Piano was in storage for five months, and pins were fine before then. No rust or signs of excessive moisture. No cleaners or chemicals were applied, just wire on the pins. Threaded part of the pins unaffected.

It just brushed off and now look fine. It's not rust.

Thanks for helping

Steve

Jeff,

That's where it becomes murky, because there are several ways to blue steel, and the resulting surfaces are not created equally. I've not read up on it extensively. Nevertheless, intuitively, I would regard blued steel more corrosion resistant than piano wire, because the blued surface has, to some extent, been passivated. (Which, besides aesthetics, is the whole point of bluing.) This is even more true if the blued surface is sealed against oxygen ingress, e.g. with some oil (not sure if I'd do that on a tuning pin, though.) But even without an oil seal, the blued surface is passivated. In other words: no, for my part I would not expect to find any substance that can corrode blued steel but leave piano wire unaffected.

Also, it appears that these pins were treated in the piano. (Otherwise, why are their lower parts untreated?) All bluing methods I have seen, if applied inside the piano, should have affected the string coils to some extent - not to mention the rest of the piano... So, the almost perfect border between the rusted pin tops and the rust-free coils remains very puzzling to me.

I seem to remember that we have some more chemists and materials gurus here. Hopefully, some of them will chime in.

[Edit: just saw Steve's feedback. Now I'm even more puzzled.]

Paulello makes nickel plated wire: http://www.stephenpaulello.com/en/les-5-types-daciers

I am betting it is just a case of water condensation causing surface, flash rust on the pins during storage. It did not happen to the wire because of the plating. If so, it's an odd combination. Blued pins and plated wire. Huh!

It is not plated wire.

Steve

Hi Mark:

There was no treatment at all on the pins. Out of the factory box, into the piano and never touched. No chemicals, oils, skin contamination or anything at all touched them.

I wonder if some leaky ground from the LX power supply ran a tiny current onto the piano, and the bluing and current caused this. Can't think of anything else. The bluing would seem to be the only difference between the top of the steel pins, and the steel in the piano.

Steve

Steve,

In my opinion, what's visible in the pictures, is definitely some form of rust, even if it's only flash rust.

Just to be clear: were the tops of those new pins in fact blued, but the "shanks" underneath the becket holes were not? I'm trying to understand why the pins below the string coils are pristine. If the tops were blued, but not the bottom part, that would suggest that the blued parts of the pins were in fact more susceptible to rust than the non-blued parts.

I am sticking with the strings being plated and the rust being due to condensation. Maybe there was a mix-up when the order was filled. The portion of the pins below the string coils did not rust because the bushings and pinblock, being made of wood, are hygroscopic. This created a drier area where the water vapor did not condensate on that part of the pins. the idea of the head of the pins being treated differently somehow seems to be a stretch.

Well, Jeff, I was intrigued, so I went googling for images. I found a variety of blued pins.



But no-where did I see pins that were blued only above the becket hole.

[Edit: So, if your theory is true, and there was enough moisture for condensation above the coils, but the pinblock absorbed all the moisture under the coils, should the pins not have been incredibly tight in the block?]

Hmmm, the latest references to "Fly Brand" tuning pins is from the 1950's.

And electrolysis doesn't make sense at all. That occurs between two different metals in an electrolyte, and can be lessened or increased with a DC current. It would not affect the end of the tuning pins.

Nikel plating on the strings will have saved them

Ian

Try a brushing them with a wire brass bush while holding a shop vacuum to prevent the dust settling into the piano. - I wouldn't put my tuning hammer on pins in that condition.


Enjoy.

I suspect that there was something wrong with the manufacturing process for the pins, probably cleaning them before bluing them. If it is still under warranty, they should be replaced.