In addition to the technical skills, the material is a basis for a good restoration.
It is not enough to buy current, new material. You have to have been collecting across Europe for many years. In antique shops, flea markets, household liquidations and specialty stores. Even on the bulky waste you will find historical materials that you can use at some point.
Furthermore, I have been able to cannibalize countless harmoniums of both systems (suction wind and pressure wind) over the many years. So I was able to expand and collect original material from many companies.
Furthermore, after decades of searching, I found my shops in various countries where I buy leather, felt, screws, shellac and other historical materials. Always on site to choose the truth yourself (and to have a few nice days abroad ...)
My motto is to replace the same with the same if possible. And here, too, sometimes my own archive is not enough and I fly to one of my favorite cities to search.
Here is a little insight: