Hello everyone. My beloved 1964 Petrof has ivory keys. With use, I notice that two or three keys in the central area of the keyboard tend to blacken... I don't know how to say it... besides being dirty, they almost seem worn... not yellowed... they seem to be losing their whitish patina... becoming dark... I tried cleaning them with salt and lemon... but they stay clean (so to speak) for a couple of months and then we are back to square one... that darkness reappears, which is horrible... the tuner, who is a very skilled technician, can he do something in your opinion?... I would lean towards the definitive "cure"... namely the replacement of the lower key veneers with an equal number of ivory veneers... Thanks for the advice. Bye!
Ivory is very porous! If its surface is polished, it manages to be more repellent towards impurities and sweat. In my opinion, salt and lemon are not good. It could be that the ivory absorbs the lemon juice (acid) and tends to oxidize on its surface! Wait Paolo, but I believe that a careful and delicate sanding with bodywork sandpaper (but dry) 1800 grit and then some polish to make the surface mirror-like should solve the problem! I think that for cleaning, alcohol is more suitable.
I don't think ivory spare parts can still be found for obvious reasons!
There is no need to think about replacing them! If the keyboard is still good and the keys are not worn down, they can be polished. There is a special abrasive called Tripoli. You must use cloth discs. No alcohol. No other recipes.
Leveling ivory is difficult. Porosity can increase if corrosive ingredients are used.
If they happen to darken due to specific sweat, they should be cleaned with a little damp cotton and a drop of dish soap. It won't be shiny, but it will be clean and you will be able to play well on it.
Do not close the keyboard cover. The ivory must be exposed to light, otherwise it will yellow!!!! This tells us that it is always a "living" material.
from what I can see, that key is corroded. Some "experiment" might also have been performed. Furthermore, it no longer has the thickness required to be shaved down. How many keys are in this condition? The restoration work is difficult. Should ivory plates (to be worked and shaped) be found, we would need to check the color and perhaps move some plates so as not to notice the contrast. In short, one must see if it is worth doing.
So, being a king, one can unglue a last treble or bass king and replace it with the damaged one. The "donor" is replaced with a new, appropriately shaped small plate.
If by any chance you haven't managed to solve the problem yet, the best solution in the presence of dirty or yellowed ivory consists of using hydrogen peroxide (200 Degrees) which you can find at a paint shop; dilute it in a small bottle with water, 50/50 ratio (half), apply it with a small brush on the key, wait (about 2 min) for the corrosive effect to act, it would be important to expose everything to sunlight which helps whitening a lot, then clean the surface well with cotton and water (clearly wrung out and not soaked).
Once everything is dried, use sandpaper 1000 and subsequently 1600 or 2000.
Repeat the operation with hydrogen peroxide if not satisfied with the result.
To polish everything, in a hardware store you can find a felt disc screwed onto a drill bit to be applied to the latter (about 10 euros); also ask for a polishing paste which you can also find in the form of a small block or stick, apply some on the felt and then polish the key with it; in a few seconds it will be like a mirror.
P.S. I polished my entire keyboard this way; it's long work done for all the keys but the result was spectacular, plus the tactility of the cleaned and polished ivory is the non plus ultra.
Attention, I must give you a couple of warnings: 1) use kitchen rubber gloves, otherwise the hydrogen peroxide will burn you; 3) it would be better to work on the key free from mechanics (otherwise isolate the key from the others, protecting them with newspaper and tape).
2) it is not a difficult job but requires a certain manual dexterity................
watch out for hydrogen peroxide. And then I take the liberty of suggesting a cloth disc instead of felt. It is important that the ivory does not get too hot, otherwise it might "burn." That is to say, the surface layer dies. Hydrogen peroxide can be corrosive. Anyway, I am warning you that the fewer products used, the better. In Tanzania, when processing was still permitted, I saw Black people polishing ivory figurines in the village with a long cloth rag and BRASSO, a sort of very fine abrasive paste. All by hand, pulling the long cloth from one side to the other by two people. ...I might also have an old slide....but I cannot guarantee finding it among my "memories" of Africa.
how long ago did you perform this operation with hydrogen peroxide?
since ivory is porous, have you considered the possibility that you didn't completely remove the product and that it continues to oxidize the ivory even in microscopic amounts?
I don't want to be controversial, but it is a very common method in restoration (I worked for 15 years in a workshop); it is not the only method, but it is certainly one of the most used ones, especially if you need to clean areas where there are marquetry, which otherwise you wouldn't be able to reach.
As far as the intervention on the piano is concerned, 2 years have already passed.
The corrosion only occurs on the surface; it is a targeted action, and then the various steps with sandpaper completely eliminate any—however unlikely—corrosion.....
Polishing is one thing, intervening on stains is a different and more invasive operation; just by rubbing, the yellow will hardly come off.
I don't want to sound condescending, I repeat, this is one of the techniques used in the workshop where I worked.
Furthermore, I am open to any other method, as long as it works.....
There is no need to argue. In fact, in workshops, various methods passed down from craftsmen of the past are convincingly used. I remember as a boy seeing American pianos arriving by sea in several workshops to be restored. The action LOOKED NEW. I was fascinated by the piano and the work performed on it. I asked the old craftsman and he told me they were sandblasted!!!!! Then I saw, in another workshop, perfectly repainted grand pianos and asked how they were treated (since I had an old Bechstein and would have liked to own it polished!!). They replied that it was done by a car painter who put the piano in an oven!!!!. In another workshop, I saw the strings being changed on a grand piano. Fantastic, it was the first time I had seen that magical work. I had heard that the different "packs" of steel wire each contained steel wire of a different diameter. Seeing the technician using the packs at random, I asked if he knew the diameters of the old strings already removed. I remember him shrugging his shoulders and replying: "..so what? In the meantime...."
I also learned that they used hydrogen peroxide to whiten ivory, so I went to see the work, pretending that I would commission that intervention on my piano. Corrosion, sandpaper, and a bit of car painter's abrasive paste. Only an "onion skin" of ivory remained and the surface was anything but polished (...which is to say... polished... if it is too polished the fingers stick... if it is too satinized.... the fingers get dirty........the important thing is not to make it "dead" and porous)
Now please don't hold this story against me. It's not about the workshops you have attended. ....but the little stories I have told are true!
I understand perfectly well what you mean, under the word restoration hides a ton of "bullshit".............
The techniques and methods are manifold but it is the hand that uses them that makes the difference, just as the sheet music is the same for everyone, but it is the performer's hands that make them unique or terrible.
Hello, last Saturday I cleaned a keyboard of an old Krauss Renner; on the first key, once extracted from the guides, I read a name "Alessandro... illegible surname.., Ventimiglia 1928". I should preface that being an organ builder, I don't mistake an ivory key for a plastic one!!!
The keys were blackened not where they are pressed but on the sides, as happens on white Mac keyboards. Industrial degreaser wouldn't remove it. I tried on one key to sand with very fine paper and then polish with a disc (felt in my case) and blue metal abrasive paste. The black from the paste became embedded in the final result. So I tried Sidol which whitened it! (with a bit of golmito oil). Now I will try to polish them with a new cloth disc and Tripoli paste as suggested in this forum.
But my question is: how do I see if it is ivory or something else?
P
Pianoaccordatore
Reply 16 by Pianoaccordatore
Ivory is recognizable to the touch because it is quite porous.
Of course. I would even say from the grain... unless they are resin keys where the grain has been imitated. Ivory keys are almost always in two pieces: the plate and the strip... but not always.
tomorrow I will try to post a photo, they have confirmed anyway that it is ivory, but it shows no signs of yellowing.. and they are intact, I haven't noticed any graining like one of the harmoniums I have in my shop, which is also in two pieces.. boo
