Casting Techniques
Creating objects from metal using casting techniques has been known for centuries. Jewelry, weapons, and clothing accessories—such as buttons or buckles—were made this way. These methods, first used almost 9,000 years ago, are still employed today in a slightly improved form.
Casting an object, simply put, involves pouring heated, molten metal into a mold, where it solidifies into the desired shape.
There were two main ways of making such molds. The first method—the so-called lost-wax technique—allowed the mold to be used only once, making the resulting object unique and unrepeatable. First, a model of the object had to be carefully sculpted from beeswax. This wax model was then covered completely with clay, leaving only a small hole, and placed in a furnace. The heat caused the wax to melt and drain out through the hole, while the clay hardened into ceramic.
In the fire, a casting ladle—a ceramic vessel resistant to high temperatures—was also placed, in which metal lumps, such as silver, gold, or a copper-tin alloy (which melts together to form bronze), were heated. At high temperatures, sometimes reaching 1300°C, the metal became molten and had to be quickly poured through the hole into the mold.
This type of mold was single-use—it had to be broken to access the metal casting. Finally, the casting was finished by trimming away unnecessary parts (such as the channel through which the metal flowed and solidified) and then filing and polishing the completed product.
The second method of casting could be somewhat more time-consuming, but a well-prepared mold allowed the production of dozens, even hundreds or thousands, of identical objects. In this case, the mold was made from soft stone. A negative of the object had to be carved into the stone block. The mold could be single-piece—when one side of the object was smooth—or consist of two or three parts if the object was three-dimensional.
Notice that, besides the cross mold itself, there are also two channels leading outside the mold. One at the top, through which the metal was poured, and one on the side, through which air escaped from the mold, allowing the metal to flow freely into all the crevices.
You can make a similar mold and casting easily at home!
We’ll just use slightly different materials…
Activity:
Create your own mold and casting!
To make the mold, you will need clay and sculpting tools (a regular stick or toothpick will also work). The decoration will be cast in plaster, which can then be painted.
Below you will find a PDF file with instructions to download. You can make the mold according to your imagination, or use our ready-made designs to download and print.
The instructions can also be used to conduct classes at school.
Learn more about the mold found at Lublin Castle
Casting mold, National Museum in Lublin (wmuzeach.pl)
See what a casting ladle looked like
Casting ladle, National Museum in Szczecin (e-zbiory.muzeum.szczecin.pl)
Watch the pendant casting process presented by the Archaeological Museum in Biskupin
Video of a lost-wax casting demonstration (youtube.com/histmag)
SOURCES
Garbacz-Klempka A., Rzadkosz S. (2014): Analiza technologii odlewania z epoki brązu i wczesnej epoki żelaza na podstawie form odlewniczych z osady kultury łużyckiej w Grzybianach. Legnica-Wrocław.