I want to share my experience of re-gluing white keys due to them detaching from the pivot. In the past, because of this problem, I requested two interventions that were unfortunately not successful.
When the problem first appeared on a key, as it detached, it would get stuck in the wooden rail (the one that rests along the piano keyboard). The technician decided to fix it by sawing off the front plastic segment of the key and then fixing it firmly onto the front pivot (a huge mess! Alas, if I could go back in time, I would never have allowed him to do that!). Subsequently, the problem manifested on other keys as well. In this regard, I hired another technician who had the patience to unglue the keys and then re-glue them (here too, something must have gone wrong, perhaps due to the choice of glue or the lack of a clamp to ensure fixation on the front side of the key).
Given the failure of the aforementioned experiences, I took courage and embraced the proverb "he who does it himself does it for three"!
Following instructions suggested to me by the manufacturer "Bösendorfer", I proceeded as follows:
1) I placed a damp cloth on the white key. I then applied an iron onto it in two 4-second intervals, heating the white key before completely detaching it from its pivot using a lever.
2) I removed the old glue from the white keys by soaking them in hot water. Then I removed the glue by scraping with a utility knife. As for the old glue on the pivot, I proceeded to remove it using sandpaper.
3) I re-glued the white key to the pivot using a PVC-E vinyl glue recommended by the manufacturer.
4) To ensure fixation, I used two clamps, attaching them to the two extreme ends of the key, and one to fix it to the front tip.
I performed this procedure on 13 keys and so far I am happy with the final result.
I also bought a new German white keyboard to remedy things should any inconvenience arise. The color is right, but they have a wider back side, so the difference would have been noticeable. A pity! I would have liked to change the first key sawed by the technician, but unfortunately, I think I'll have to keep it as it is. It will be the memory of this improvised adventure of mine.
I am attaching some photos
