Following further research I have made up some clay balls with a mixture of malachite and charcoal inside to smelt. Copper results from removing oxygen from the copper ore, so the sealed clay balls should be more successful that the pit smelt that I did at the Sculpture Workshop.
I like the way the clay balls look a bit like poppy seed heads.
I’ll let them dry out a bit before I try and get them to smelting temperature in a charcoal furnace.
I have been awarded funding for my Stone to Bowl project. It will pay for several weeks at the Scottish Sculpture Workshop in 2018 to complete the project which will take copper ore through to cast pieces, using traditional and fully sustainable methods.
I’ve been doing some preparatory work:-
I experimented with melting the copper that I pit-smelted this year at the Sculpture Workshop, adding in some silver to lower the melting temperature. I melted 115gm and got 74gm of copper and some residual oxides which didn’t melt. The left hand metal is copper, the right is the original smelt material which is less pure. Next trial will be to sand cast with the copper/silver alloy.