Bronze Casting is a very old and ancient art form
Bronze casting started around 3000 B.C and was used to make weapons and other artifacts for the Greek civilization. As civilization advanced, bronze sculptures and reproductions of animals and human forms soon became popular among the population. These reproductions were more commonly made in clay and not on a bronze cast. During the Hellenistic period, these reproductions developed even further and were used to create small items and later developed even better ones.
Bronze casting is also known by the names cast bronze, hot rolled cast bronze, poured bronze and pressed cast bronze. Bronze casting can be done with either melt-casting or hot forming. For small items, it can be done with the use of cold cast bronze, which is considered as the best option. However, when it comes to larger sculptures, either hot or cold formed are used to produce them.
Casting is done using molds and there are two types of bronze casting commonly used today
The first one is cold-forming, which uses a high-pressure type of pressurized molten zinc (usually Zinc-based) or Aluminum. This process is controlled and the molten metal is allowed to cool down to room temperature which is needed to solidify the design. This method is widely used for mass production as the molds are very easy to clean and remove any debris during the manufacturing process. The second kind of cold-forming is hot-forming, which uses a different pressurized liquid which is then ignited during the melting process to melt the alloy. The main advantage with this process is that there is no need to place the mold very close to the object that needs to be made as the melted material flows into the molds with much ease.
When it comes to the traditional moulding methods, the most common one is the hot wax process casting. This requires a large mould with a negative pressure and the hot wax is shot through the molds at extremely high temperatures. The cooled product can then be removed from the molds and re-assembled by the client. The disadvantage with this moulding method is that it is time consuming as it requires a large number of moulds and it also costs a lot of money as it consumes a lot of metals and natural raw material.
Bronze Casting can be broadly divided into two major forms
On the other hand, the new ceramic mold technology offers a convenient and fast way to manufacture cast bronze sculptures. It uses special micro-spheres which contain ceramic salts. These salts cool down the molten metal until it becomes solid again which in turn seals the pores of the mold. To enhance the quality of the final product, the finished product is then carefully inspected by an expert before it is packed.
In welded-together casting, several pieces are melted together in a similar fashion but are separated until they reach a temperature of almost 1800 degree Fahrenheit. Once the pieces reach this temperature, the molten metal is allowed to cool down in the form of liquid and this liquid is then injected into a specially designed mould. Once the mould is opened, the ceramic bits are melted together and the whole mold is closed so that no part of the piece escapes. This type of casting is usually more expensive than the earlier type of casting.