Everything we create at Brooklyn Bambini is made using the lost wax method, a process that has remained largely unchanged for 5000 years. The name refers to the wax being vacated from the mold, hence the word lost with the void in the mold being filled by molten metal.
The original Brooklyn Bambini labor talismans were conceived in wax and worked-up several times in plaster before I made an alginate waste mold. This step allowed me to make several versions of the originals in wax, the purpose being to refine the forms. When I was satisfied with the two baby figurines I made silicon rubber 2-part molds, which makes it possible to produce multiple waxes.
Individual wax models are gated which means arteries are attached to the main body of the sculpture to feed the liquid metal. Once gated, the object is invested or coated in a fire/heat resistant material. Early in the history of this process investment material was a combination of mud and straw or sand. Today, investment material is composed of silica sand and refractory cement.
In the lost wax process every object produced begins as a wax, and every object produced requires the destruction of its final mold, the investment material, in order to liberate the raw piece.
The foundries where Brooklyn Bambinis are poured are equipped with furnaces capable of reaching 2000 degrees or more. The invested molds are put into burn-out kilns where the wax figures evacuate, simultaneously pre-heating the molds. When the optimal pre-heat temperature is reached, they are removed from the kiln and molten metal is hand-poured into the molds. When the metal is cooled the objects are divested, meaning the investment shells are literally broken off. Nothing remains of the final molds.
The foundry passes-back completely raw castings. Once back in the studio, the feed gates are removed first. Next, the surfaces go through a series of filing and grinding procedures to achieve the desired surfaces. All pieces are hand-polished.
The degree to which something is polished will produce variations between highly reflective, glossy surfaces and more subtle, matte surfaces. Over time all metal surfaces will develop a patina due to exposure to atmospheric elements such as oxygen, carbon dioxide and water as well as through handling. The oils in the skin will react with the metal bringing out warmer tones on the points of greatest contact while the recesses will remain darker.
To learn more about the lost wax method of casting, click on this link.