We often mention the traditional techniques our craftsmen use to create the beautiful silver creations that leave our workshop - but each of these techniques, passed down and evolved over the centuries, is worth exploring. In this series, we’ll examine some of the techniques at the heart of British craftsmanship taking place in our workshop every day.
In our last instalment, we discussed the skill that goes into creating a mould for casting silver - it takes a steady hand and an extremely hot kiln to create a finished mould, but once that part of the process is complete, our craftsmen are able to bring in the precious metals, safe in the knowledge that their mould will provide a consistently high quality finish.
Based on the volume of the wax master, our silversmiths calculate the correct quantity of silver, which comes as grain, similar to the size of a coffee bean, nowadays we use recycled silver.
Using a graphite crucible, the silver grains are heated to 1010°C within a pressurised nitrogen chamber. Below, the plaster mould flask waits for the liquid silver to be forced down into it, filling the space left by the melted wax master. Before high pressure nitrogen and vacuum technology was available, a centrifuge was used to drive the liquid silver into the mould - silversmiths would swing the red hot flask around their heads, which was extremely dangerous, and yielded unpredictable results.
Once the silver has filled the mould, the hot plaster will be dropped into a water bath, where it will dissolve, leaving the freshly cast silver behind. Any traces of the plaster that have been left behind in the process are cleaned away using a high powered spray. We give the silver cast an acid bath to clean away the light oxidation on the surface, and the process of casting is finally finished.
Discover how the process of casting works in the first half of this instalment of The Silversmith’s Toolkit. To view the finished product, take a look at our collection of the finest British craftsmanship.