March 27, 2016 – Zimbabwean artist-jeweller Patrick Mavros uses the ancient technique of lost wax casting to ensure exceptional results for his sterling silver animal designs.
To obtain a silver sculpture of the original wax model is a long and involved process. The wax model is encased in liquid rubber which, once set, is carefully cut away to provide a ‘negative’. Into this cavity, molten wax is injected, allowed to cool and removed from the rubber mould in the form of the original.
After thorough checking, the new wax model is covered with plaster of Paris and fired. The heat melts the wax, which trickles out through a tiny aperture. All that remains in the plaster is a perfect hollow in which every surface detail of the wax model is captured. Molten silver is then poured into the plaster mould.
Once the silver has cooled, the plaster mould is broken open to reveal the silver casting. The casting is then cleaned and checked to see that every detail of the original has been faithfully reproduced in silver. Finally the piece is hallmarked and polished.
Silver in Zimbabwe
In Zimbabwe, silver is a by-product of the gold refining process.
The people of Zimbabwe have mined and panned for gold for 500 years. The original gold miners worked the banks of rivers like the Mazowe, Angwa and Revue. They packed the gold granules into porcupine quills, sealed them with beeswax and for 400 years, sold the metal to the Portuguese of East Africa.
Zimbabwe now produces 60 tonnes of gold annually. The gold ore normally contains traces of copper, silver and lead and it is during the gold refining stage that fine or pure silver is extracted.
Pure or fine silver is too soft to be used for coinage and silverware, sculpture or jewellery.
The British Silver Alloy of 92.5% silver and 7.5% copper has been in use for over 800 years and was used in Anglo Saxon pennies. The word Sterling Silver originated from the word Oosterlings. King Henry II employed “Oosterlings” from Eastern Europe to assay coinage and silverware and it was then that 925 parts of silver in the thousand became the minimum assay standard known as Sterling Silver. The word Hallmark originated from the fact that the metallurgists or Oosterlings used town halls in which to assay and mark articles of silver.