The first step in the process of building a viola is to order the wood, spruce for the top plate (tavella), maple for the bottom plate (fando), the ribs, neck, and scroll, ebony for the finger board, and thin strips of pear wood for the purfling. The quality of the wood makes all the difference in the world. The professional violin wood catalogues have five quality levels from which to choose. Because this was in all likelihood my only shot at building a viola, I decided to go for the best, which cost about $1,000...for just the wood! The best wood, by the way, comes from a tree which grew in poor soil, meaning it had to be strong to survive. The resulting wood is more dense and has better echo. The best slabs of wood are also cut from the north side of the tree, which is more dense than wood from the south side. My wood came from Slovakia.
The next decision is to choose a model to replicate. Harold and I chose an 18th century Mantegazza. Pietro Giovanni Mantegazza, who lived in Milan, was primarily known for his exceptional violas. Harold had a form for a Mantegazza viola which he let me use, saving me many hours. A stringed instrument is built around a plywood form, which is eventually removed in the later stages of the process. The form has slots for holding the instrument safely in various stages of the building.
The first actual building step is to prepare the tavella (top plate), which is made of two joined slabs of spruce. The original pieces of wood are about an inch thick. They will eventually (almost 400 hours later for me) be thinned down by hand to 2.5 mm with a pre-set scientific arch, inside and outside. Before joining the wood, the two edges must be smoothed with a large plane. Then the two pieces of wood are glued and placed in a press for a day.
Next we cut six square blocks out of a piece of the spruce and glued them onto the plywood form. The glue used for violin building is made from animal hide scrapings, and comes in various strengths, according to the job you are about to perform. One block goes at the top, one at the bottom, and two on each side of the center area. These curved indentations on either side of the bridge area are called C Bouts, and one of the blocks is glued to each end of the "C".
After the blocks have thoroughly dried, they need to be sanded absolutely even on a large sanding board. From this point on, everything is built onto these six blocks, and nothing else is attached to the original plywood form. The blocks need to be smooth because all the other parts of the viola will to be attached to them.
Now comes one of the more difficult and tedious jobs, bending the quite thin pieces of maple for the ribs (the wood which joins the top and bottom plates) into curves that match the shape of the form...without breaking the wood. This step was incredibly intimidating. The wood was expensive and there is only so much of it. For the best sound and look, all the wood must match, so the thought of ruining any of it was a worry. First the wood is soaked in heated water while an upright, circular iron is heating up. The the wet wood is placed carefully inside a piece thick leather (to protect our hands), and pressed ever so gently against the iron. Slight pressure is exerted to start the bending while the wet wood bubbles and steams. This bending of one small piece of the rib wood will take up to 15 minutes. Harold explained that the wood tells you when it is ready to be bent more. It is instinctive, almost mystical. You cannot hurry up the process. You keep comparing the amount of curve you have achieved with the curve of the plywood form, until eventually they match. This process takes several days, but soon the ribs are glued to the six blocks (which are attached to the form).
Showing posts with label Pear wood. Show all posts
Showing posts with label Pear wood. Show all posts
Wednesday, February 17, 2010
Subscribe to:
Posts (Atom)