ELECTROPLATING: Electricity revolutionized the trade of coating base metal objects with silver. Patented by Elkington and Company in the 1840s, this technique was the fulfilment of a century of research into the effects of electricity on metals. A negatively charged silver bar, suspended in a vat of potassium cyanide, deposited a coating of silver on a positively charged base metal (mostly copper, later nickel-silver) object immersed with it. Electroplated objects were fully formed in base metal before plating. ELECTROFORMING transferred the metal deposits directly into moulds in the plating vats. When enough metal had been deposited to create a self-supporting object the mould was removed. Developed by Alexander Parkes, electroforms so accurately mirrored the moulds in which they were created that multiple copies could be created called ELECTROTYPES.
ELECTROGILDING exploited the same technique but used gold bars instead of silver. It was safer than traditional mercury gilding.
During the electrotyping process a mould was taken of the original object. The moulds were made from gutta percha or plaster. Gutta percha was a tree-resin from Malaysia that could be melted and poured onto an object, but would set hard and take a perfect impression. During cooling it could also be manipulated. When the mould set, it was removed from the original object and then lined with graphite or plumbago to make it conductive. This mould was then immersed in the plating vats for coating with copper.
A mould was taken of the original object. In this, a copper impression was electroformed. This became a 'type pattern'. The type pattern became the source for future moulds to be made to save going back to the original object, which might be fragile or, in the case of objects in private or overseas collections, inaccessible. This then was electroformed in copper from moulds made from a type pattern which itself was electroformed in a mould of the original object. The copper electrotype was then electroplated and electrogilded to look like the original object. The final electrotype is therefore two stages removed from the original object, but is still a highly accurate impression.
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