Making the Body
The soundboard is the heart of the piano, and how it is made is an important process in terms of sound.
The soundboard is a thin wooden sheet made from carefully selected Sitka spruce or Japanese spruce. Before being used, the wood is air-dried or kiln-dried to a specific moisture content. The soundboard is assembled from many small planks that are glued together edge-to-edge. The large sheet is cut into the desired shape and planed down to the proper thickness. It is then seasoned (dried) specifically to match the climate conditions where the buyer of the piano lives.
Ribs are then glued to the underside of the soundboard, in a direction perpendicular to the grain of the individual boards in the soundboard. This is done so that the sound vibrations are transmitted uniformly throughout the whole soundboard, and serves to reinforce and stiffen the soundboard, which is weak horizontally. The long bridge and the short bridge are attached to the side opposite of the ribs.
Once the finished soundboard is set in place on the inner rim and the metal frame attached, the piano is almost complete.
The frame is basically cast iron mixed with some additional metals for acoustic properties. The metals are melted, mixed, and poured into a mold made of sand to cool and harden. The frame weighs anywhere around 100 to 150 kg.