This cello had an ill fitting soundpost that was not in the right location.Therefore it didn’t support the top against the tremendous strain of the string tension down on the treble foot of the bridge and eventually the soft spruce top developed a crack. In order to repair this crack you need to first glue the crack and then fit an inlaid patch into the top forming a “landing pad” of new wood for the new soundpost. Without this new patch the immense pressure down on the post post would simply force the crack open again. The first step is to carve out the spruce at the post area. At its deepest point the top is left 1 mm thick. The photo shows light from behind the cello streaming through the patch area. In order for the patch to the completely fit the scooped out shape of the top you need to use chalk as a transfer material. The surfaces must fit exactly so that no distortion of the top will be visible on the outside of the cello. If the patch doesn’t fit well the top will show the imprint of the patch. The chalk must thoroughly cover the patch before it is glued in. Once glued in, it is trimmed and carefully scraped to blend with the contour of the top. Notice that the dark, winter grains of the patch are at a slight diagonal to the grains of the top. This provides added strength by spanning the crack, rather than the grains of the patch running similarly with the top, with the chance that the patch could both soft summer grains over the crack with the soundpost exerting its pressure there and re-opening the crack
