Trade Secrets: Cleaning and repairing surfaces before closing an instrument top

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By Guillaume Schönau

Violin maker and restorer based in Quebec City, Canada

In building a stringed instrument, there are many techniques to make them as strong and durable as possible. In particular the thin ribs, doubled with internal linings, allow for very slight contact with the top and back plates. This creates a delicate balance between the instrument’s solidity and the freedom for the soundboard to vibrate.

The simple but revolutionary idea of leaving an overhang at the edge of the top and back makes it possible for the plates to expand and contract without cracking the soundbox when gluing. This also allows a repairer to open an instrument and work on the inside, so they can be kept functioning almost indefinitely.

Over time, repair work ends up altering the surfaces of the glued sections, especially those of the spruce top. As a general rule, the older the instrument the more it exhibits marks of previous work done to it. This is why it is essential to examine the condition of the top’s interior surface, as well as the edges of the ribs and linings before closing the soundbox. The quality of this assembly is crucial for future maintenance of the instrument and its sound qualities…