Cuttlebone is the chalky internal shell of a ten legged, squid-like mollusk known as the cuttlefish.
It has a hard, thin crust on the outside which surrounds the internal softer shell, the soft side is composed of a calcium carbonate, which is almost pure calcium. Cuttlebones are found on beaches after sea storms and until recent years were seen, hung by a string on the walls in goldsmith’s workshops. Cuttlebone casting is an ancient technique that was used in Mediterranean countries for centuries. Belt buckles made by German goldsmiths have been found dating before the seventh century. Since then, this method was employed throughout history from Italy to Greece, from France to England Until the end of the 1950’s it was utilized by the largest gold manufacturers in the world for mass production. With the perfection of centrifugal casting, the cuttlebone technique became too time consuming and is no longer used by industry.
Today, cuttlebone casting is mostly used by artists and craftsman. There are numerous ways to create a mold for cuttlefish casting. The procedure outlined is the direct method of carving into the bone.
Cuttlebone is easy to found in the nature, they are found on beaches after sea storms.
Usually people selling cuttlebone in pet store, as a bird’s snack for their intake of calcium.
Cuttlebone casting is a very natural method of casting metal.
STEP 1: PREPARE THE CUTTLEBONE
Use a spiral blade in a jeweler’s saw to remove the pointy ends of the bone, cut the bone in half as shown.
And use sandpaper to flat surface to sad the soft side of each half, make sure the carving surface is flat. Place the two soft sides together and rub them against each other to eliminate any slightly uneven surfaces.
STEP 2: CRAVE THE MOLD
Use a pencil to draw your design on the soft surface gently. Do not press too hard with the pencil, as it can actually leave an impression that will cast. The finished cast object will be a reversed image.
Use any sharp tool to carve. The deeper you carve, the thicker the finished cast object will be. And carve the sprue gate into both halves of the bone, gently removing the soft surface.
STEP 3: CASTING IS READY!
Bind the two halves of mold with binding wire.
Place the cuttlebone mold on a fire-resistant surface in a well-ventilated soldering station.
STEP 4: CAST THE METAL INTO THE MOLD
Melt the metal.
Silver melting point is 962 degree Celsius; Gold melting point is 1064 degree Celsius.
Pour the molten metal directly into the mold’s sprue gate. Fill the mold until the sprue gate is full and no more metal can flow down into the mold. Make sure the mold is totally cool down before you cut the binding wire and open the mold.
STEP 5: CLEAN UP THE CASTING
Use copper tongs to put the casting in warm pickle to remove any remaining oxides.
Saw off the sprue button with a jeweler’s saw frame, and use files, sandpaper, to make the metal a fine surface finishing. Soldering/hammering/setting stone is needed consider special designs.