Trade Secrets: Repairing a bow thumb groove with epoxy and modelling clay

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By Iris Zhulla

Violin and bow maker based in Thessaloniki, Greece

One of the most common forms of wear on a bow comes at the point where our thumb touches the stick. Constant rubbing of the pernambuco with the thumb, in addition to excessive or acidic sweat, causes the wood to wear down, leaving a groove, in this case, a very big one. Restorers can fix this kind of wear using a two-component transparent epoxy resin, also called liquid glass.

One of the advantages of this technique is that all of the original wood will remain intact. It is not filed or levelled, just cleaned very well. The epoxy is durable and it will hold for many years. And if a restorer would ever like to bring the bow back to its original state before it was repaired, one can easily destroy the epoxy little by little, and when the thickness is very small, peel it right off the bow.