Silver, the most brilliant of all metals, is commonly used in jewellery and coins. Highly ductile, or easy to bend, it can be shaped into everything from teapots to figurines. But silver can also be cast as well as hammered. To cast silver, you need to melt it first.
Break an alloy such as sterling silver into pieces so it can fit into your crucible. Pure silver is rarely used to make anything because it is very soft. Objects made out of pure silver can collapse under their own weight. Sterling silver is much harder than pure silver. A crucible is a heat-resistant container that is used to melt metal on a furnace. Normally, a crucible for silver would be made of clay or graphite.
Take your crucible and put it on a furnace. The furnace must be able to attain extremely high temperatures. Sterling silver melts at 893 degrees Celsius. Heat your sterling silver until it is completely melted. While it heats, get your mould ready. The mould will also be made out of clay. Molds are best for making objects like statues or solid pieces like rings or earrings. The ring or earring can be bent to the correct shape after it is cast. To melt and cast your silver object, you will be using a method called the lost wax process. This is also known by its French name "cire perdue."
Design your object on paper or on the computer. Once you have a plan, you can begin to make the mould for it. Take a lump of wax and cut it into the desired shape. Follow your plan as closely as possible.
Place the wax inside a metal pipe, once it looks like the object you want to make. The metal pipe must be large enough to hold the original wax object and the plaster that will go around it to make the mould. Both the wax piece and the pipe go on a "sprue" base. This is a fireproof base with little tunnels cut into it to allow for the wax to melt out. A similar sprue will also go on top. This should be a small cup of wax. Additional sprues will also go along the sides to act as vents. To cast the silver, you will actually have to get rid of the wax.
Let the plaster harden. Take the mould and heat it. You do not need an extremely hot furnace. You just need to melt the wax. Melt the wax and let it run out through the sprue at the bottom. When you are done you should be left with an empty mould. Now you can cast the silver. Get your molten silver in the crucible and pour it into your empty mould through the sprue hole at the top. Make sure you do this on a heat-resistant surface. Do not overfill the mould. Your silver will take quite awhile to cool.
Break open your mould when the silver is cool. The piece should look just like your wax original except for the tiny bits of silver that will be attached where the sprues were. Polish these off. The piece should be ready to use.
More complicated pieces may require several moulds. You can join, or solder, these together later. You can also bend thin pieces into different shapes and hammer in designs, or chase the silver.
Be careful when working with high temperatures and molten metal. Use non-flammable work surfaces. Do not wear flowing clothing. Don't splash the silver when you pour it.
Tips and warnings
- More complicated pieces may require several moulds. You can join, or solder, these together later. You can also bend thin pieces into different shapes and hammer in designs, or chase the silver.
- Be careful when working with high temperatures and molten metal. Use non-flammable work surfaces. Do not wear flowing clothing. Don't splash the silver when you pour it.