Removing the mould after gluing the linings

Lutherie

Makers reveal their special techniques

One peculiarity of the ancient Cremonese method is that makers would glue the linings to the sides of both the top and the back before removing the mould. This can be deduced from the toolmarks found on the original Stradivari moulds preserved in Cremona’s Museo del Violino. Keeping the ribs on the mould guarantees their stiffness when it comes to finishing the outside with ascraper. It also ensures perfect correspondence with thetracing marks on the top and back when they are glued to the ribs once the mould is removed.

For the old Italians, another advantage would have been that stable ribs facilitate the fixing of the neck with nails, as was done in the time of Stradivari This part of the process is no longer necessary when it comes to making modern violins, but the other advantages described remain valid and useful.

Although it may seem that the presence of the linings would make the extraction of the mould impossible, this operation is in fact rather simple and risk-free. However, some rules must be observed in order to carry it out successfully.

The mould is centred on the ribs

ALL PHOTOS DAVIDE SORA

1. The mould must be centred on the ribs, otherwise there will not be enough space to accommodate the linings on both sides and its thickness must not be higher than 13.5-14mm. The linings of the C-bouts must be embedded in the corner-blocks (a typical Cremonese feature) to guarantee the necessary strength and elasticity of the rib garland. It helps to rough out the cornerblocks down to the level of the mould, and to rough the linings near the top-block on the top plate side,and near the bottom block on the back plate side.

Cutting down the corners

Care must be taken during this part

2 First I use a fairly flat gouge to cut the corner-blocks on both sides, down to the level of the mould. I split the wood paying attention to the depth of the cut, so as not to damage the mould. Then I cut the wood by supporting the corner with my fingers. This is a potentially dangerous operation because the cuttng action is directed towards the fingers, but if done correctly (by cuttng with a slight rocking motion without pushing too hard), there won’t be any real risks.

The linings are cut with a slanted bevel

3 It is not strictly necessary to cut the linings with a knife by making a slanted bevel, but it does facilitate the extraction of the mould. Stradivari probably cut the linings around the entire perimeter and on both sides before removing the mould, as can be deduced from the scratches on the originals left by the knife’s tip. I prefer cutting the linings near the top- and bottom-blocks only, finishing the job with the ribs free from the mould for better visibility, and to avoid cutting into the ribs.

Ungluing the corner-blocks

4 With a sharp hammer blow I unglue the corner-blocks first, holding the block firmly with the fingers to absorb the impact. This might sound traumatic, but if the right amount of glue has been used on the block, a gentle but firm blow is enough to detach it. In addition, most of the time it will be the wood that splits and not the glue that breaks, so there will be no problems even if too much glue has been used by accident.

Removing excess wood from the corner-blocks

5 Before ungluing the top- and bottom-blocks, I remove the excess wood from the corner-blocks by splitt'ng it away with an opening knife sharpened at the tip, and then finish off the roughing. This allows the corner-blocks to clear the edges of the mould, ensuring the ribs have the necessary freedom of movement to allow the larger blocks to be lifted

A wooden block distributes the force of the blow

6 Now I unglue the top- and bottom-blocks with a sharp hammer blow, using a wooden block to distribute the force of the blow over the entire surface. It is advisable to repeat the operation on both sides, to ensure that the block is definitely unglued

Widening the C-bouts

7 I gently widen the C-bouts to make the corner-blocks come out of their seats, allowing them to go over the edges of the mould (which would otherwise prevent the lifting of the top- and bottom-blocks, making it impossible to extract the mould)

Removing the mould

8 Now the mould can be taken out from the side of the top, starting at the top-block. I gently lift the block until the linings can go over the mould. Then I push the mould out and extract it by rotating it on the lower maximum width of the ribs. If there is not already a way of telling which side of the ribs is the top, remember to make a mark on the side of the back or the top, to avoid confusion once the mould has been removed.•