In Radbon Workshop no chemical materials are being used such as PVA glues, titebond etc. There are scientific reasons why we should avoid these glues for even repairing our ordinary furniture let alone musical instruments. Here you can read why:
The same for varnishing and polishing the surface of these historical pianos. We only use historical varnishes (not only shellac which was one of the many varnishes) historical waxes and very rarely historical oils.
The strings we use are also indeed the best we can find (P-wire, Vogel and Paulello for post 1820 pianos) and according to the historical pitches appropriate to the thickness of the strings, knowing that too high pitch, thick strings and for some pianos or clavichords the high angle of the strings to the bridge can simply damage the soundboard or twist the whole piano.
Over-restoring is also something that we avoid. We have the understanding and also try to explain it to the clients that removing soundboards because of a few tiny cracks is not necessary (one can repair them without removing the soundboard) and it is necessary when structural parts (like the wrest-plank) are tilted and have lost the glue etc.
Over-restoring in anything only destroys the historical value of these historical pianos. In many cases scraping the surface because the old dirt in the wood (if it is not too much) and making it look like a new instrument is not our tactic though sometimes the old repairs and several layer of improper polishing plus the dirt and damages leaves no other possibility to remove them all and varnish it.
Over-restoring is a kind of perfectionism which has roots in our psycho. Making an old piano looking like a 6 months old piano, throwing out original and usable strings and restringing, throwing out all broken hammers, not keeping the functional parts and making whole new sets is what had formely made clients (specially wealthy ones) happy