The mold is generally made from a heat-resistant, flexible and porous material. The mix used includes different ratios of clay, goat hair and horse manure.
Liquefied bronze founded at 1200 ºCis then poured into the mold. The ideal proportion for the bronze alloy is of 78% copper and 22% tin.
The second phase consists of covering the mold with cow fat and adding the friezes and decorations, which are previously made of wax.
Bell tolls have marked the life of Brazilian cities for the past three hundred years with a rhythmic cadence embedded both with European religious influences and African roots.
At a time when tons of gold were shipped back to Portugal, slave labor extracted mineral resources metals from the earth and added new touches to the Catholic tradition of the Old World. A rhythm, a drumming sound heard from Brazilian bells alone.
The results of this mix were heard on the Brazilian church bells and eco to this day. It can also be felt in the voice of the bell-ringers who ensure the continuity of thisintangible heritage of Brazilian culture.
Approximately 900 tons of gold were shipped to Portugal from the state of Minas Gerais in the eighteenth century.
One million people had recently settled the area, having sought the rivers, sieving alluvial gold, or digging the earth, taken by the gold rush. Most of these people were slaves – it is worth recalling that only 3% of the workforce then was free.
If the gold-mining cycle has long been left behind, it is iron that currently blows wind onto the local economy’s sails. Over 160 million tons of iron produced yearly back such statement.
The bell foundry technique has been subject to very few changes since the seventh century, which has also been the case of the centenary composition of ideal bronze for improved sound. Below is further information on how a bell is made to make a bell.
The bronze is then allowed to cool down, which may take up to five days. After such period, the mold is either brushed away or broken down, and the bronze is polished.
In essence, the bell is comprised of four parts:
part that connects the body of the bell itself to the axis onto which it is clamped.
large bronze piece in obconical shape that causes the sound to reverberate. The ratio between size and height, width and size of the mouth determine the bell’s tuning.
percussive element that is a metal rod that hits against the walls of the bell, generating sound. The clapper is generally strapped with sisal or leather.
wooden structure to which the crown is connected. This part may include a lead insertion, to counterbalance the bell toll.
Each bell is different from the other. The metal alloys used, size and shape causes each bell to have a unique vibration.
Sound waves circulate in the space of the body at different speeds and proportions, reverberating different tones in each of the areas of sound influence obtained from the chime.
The set of chimes also overlap, thereby creating more complex sounds.
Bells have five main harmonics; the more balanced the intervals, the most tuned is the bell.
When the clapper hits the bell, all harmonics resonate together. Because they have different behaviors resulting from different diameters within the bell, the harmonics do not stop resonating, creating a set of sound rings coordinately vibrating on their own frequency, generating a tone and sound.
Bell tolls defined the rhythm of cities and towns for many years.
Communication between bell towers and the town dwellers was based on the number of tolls and rings.
Lei de Incentivo a Cultura
Ministério da Cultura - Governo Federal