How to Make a Spearhead by sandra46
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Description
Here you can see Franco making a spearhead. He used tin instead of copper (or copper and tin to make bronze) for practical reasons. Not only today tin is cheaper (contrary to ancient times, when it was rare and costly), but it also melts at lower temperatures than copper and it's easier to manage in a demo. You can see the different phases of the process, the mouth of the bellows made of pottery, the pottery crucible, the soapstone mold, the wooden tongs liberally smeared with clay, and the bronze knife to finish the item.
Since some of you asked about copper mining I can say that the process was known before the Copper Age, when people were mining chert,flint and especially the so-called 'green stone', like jadeite and similar stones for prestige axes. (more in the future). When they looked for greenish ore, they also found greenish/bluish copper ore together with shining copper nuggets.
Copper can be found in over 160 different minerals, but the most commonly exploited minerals are cuprite, malachite, azurite, chalcopyrite, chrysocolla and tennantite. Minerals of copper were known from ancient times. In Crete, little fragments of malachite and azurite were powdered and used as make up or decorate ceramic in an early date such as 6000 BC. Therefore, the minerals were collected because people were looking for this kind of ore because of its brightness and colour, to be used in prestige and/or religious artefacts.
To mine copper ore basically they used the thermic alteration or firesetting. This consists of applying fire to the rock and then pouring water over it. The rapid changes of temperature will cause cracks within the rocks that can be totally broken with the help of mauls and picks. Then the useful masses were selected, crushed and transported to the production centre.To melt copper out the rock it is necessary to keep a fire at least 1981°F (1083°C). This was most likely done in ancient Copper Age sites by continuously blowing a fire through tubes made from wood, bamboo or reeds. Archaeologists recreating the process need about an hour of constant blowing to produce several copper pellets. Producing copper for an ax using this method would take several weeks. Scientists believe, the heat required to melt copper and tin into bronze was created by fires in enclosed ovens outfitted with tubes that men blew into to stoke the fire. Before the metals were placed in the fire, they were crushed with stone pestles and then mixed with arsenic to lower the melting temperature. Bronze weapons were fashioned by pouring the molten mixture (approximately three parts copper and one part tin) into stone molds.
The earliest copper mining on the European continent is in the Balkans and may be dated generically to the later fifth millennium cal BC: Ai Bunar in Bulgaria seems to be dated approximately 4230-4000 BC and Rudna Glava in Serbia approximately 4670-4980 BC. Both the Prehistoric Serbians and Bulgarians dug trenches into the mountain or hillside to extract the copper by use of stone and bone or antler tools. Once they found it they broke off some of the large rocks containing the copper by heating it up and then pouring water over it to crack the rock. Then they would extract the copper and take it somewhere to smelt the copper out and make artefacts.
To know more about it (with photos of ancient mines):
http://beniculturali.altaviadeimontiliguri.it/beniAVML/resources/cms/documents/MaggiPearceAntiquityML.pdf
http://www.penn.museum/documents/publications/expedition/pdfs/21-1/jovanovic.pdf
Thanks for your kind comments.
Comments (37)
virginiese
Very interesting !
Cyberik
Beautiful photos, and very interesting explanation ! :)
tennesseecowgirl
amazing art form thanks for sharing how this is done.
mickeyrony
A lot of work to arrived at his end lol. Again a great presentation ((5++))
A_Sunbeam
Fascinating and very instructive!
danapommet
a fantastic display of Franco's trade and excellent information Sandra!
jarmila
bellissima composizione e colori, buon weekend Sandra