Bronze casting is an effective manufacturing process that has many different applications. In fact, bronze casting has made its way into the entertainment industry. For example, weapons and sculptures for use in movie shootings are sometimes designed using bronze casting techniques.

The specific process used is called lost wax bronze casting. This type of bronze casting is generally a 10-step process that involves some of the following steps.

Moulding the piece

The first step is actually moulding the piece. What is received first is the original sculpture, which could be in clay, wood or another similar material. After the piece is moulded, shims are applied to divide the mould into two halves.

A thick coat of gelatin is then applied to the plaster, followed by an encasement of plaster to reinforce the gelatin itself.

Waxing

Once there is a fully-encased gelatin mould, the original plastic mould is removed and an even coating of molten wax is poured into the gelatin. An investment casting core material is added to cater for the complex internal cavities during the process. The wax is then removed from the encasement and the imperfections are cleaned up. This includes seam lines, air bubbles, etc.

After this, wax drains and air vents are added in order to hold the core in place. Plaster investment is poured over the wax model and a hole is left at the bottom for the wax to melt and burn out. This model is then placed in a kiln. Wax burns out of the mould, leaving a hollow space that is the shape of the wax model. This is where molten bronze is poured.

Bronze Casting

Before the bronze is poured in, gating is done. This is where the artist will engineer specific points of the sculpture that the molten bronze will be poured in. Bronze has a melting point of 950 degrees Celsius. It is an alloy consisting of copper and tin, which is harder than both metals by themselves.

In order to mix the two metals, the copper has to be melted first then the tin added later. Borax is used to help remove impurities and helps the metals mix better.

Final Colouring

When cooled, the plaster is broken away from the bronze and surface clean-up of the bronze begins. This is where drains and air vents, which in the pouring process were filled with bronze, are removed. After preparation, the final colour is applied to the sculpture.

Contact a company that offers die casting and bronze castings to learn how you may benefit from these processes.