Lost Wax Casting method in making Bronze Sculptures

Lost-wax casting is the process by which a Bronze sculpture is cast in olden times. Intricate works can be achieved easily by this method. This is an ancient process dating back up to thousands of years to ancient Egypt, Greece and Rome.

It is still the best method for capturing exquisite detail in metal objects, which could not otherwise be produced given the complexity of their design. The lost wax method is still employed today in the areas of sculpture, fine jewelry, and in some handicraft work. 

It is a demanding and expensive process, but still provides great detail and individuality to the product.

The process involved in making a lost wax sculpture can be carried out by direct or indirect method. The Direct method involves making a Wax model and developing a Bronze sculpture from the same.

But the Indirect method is quite different, as it involves making a model that may not be of wax only. The steps involved are listed below in detail.

•     Making a model out of Wax or oil-based clay as these materials retain their softness. The mould is made in such a way that the inner layer is prepared from latex or silicone and the outer mould is prepared from plaster.
•    After making the mould, the wax is poured into it and left to dry for few weeks or so.
•   Once the mould is dried, the wax is removed to split up the original mold from the hollow wax copy. This copy could be reused for making multiple copies of the same sculpture.
•    Each hollow wax copy is then chased. The wax is dressed to hide any imperfections. The wax now looks like the finished piece.
•    The wax copy is sprued to provide paths for molten casting material to flow and air to escape.
•    A sprued wax copy is dipped into silica and then the ceramic shell mold material is made.
•    The ceramic shell-coated piece is heated and the wax melts and runs out. Now all that remains of the original artwork is the negative space, formerly occupied by the wax, inside the hardened ceramic shell.
•    The ceramic shell is allowed to cool. Cracks or leaks are patched with thick refractory paste.
•    The shell is reheated to harden the piece and remove all traces of moisture. Metal is melted and then poured carefully into the shell.
•    The rough casting is finally removed.
•    The filing and polishing is finally done to recover the product from any kind of shruds. The Bronze sculpture is thus made by Lost wax method.

Check out this video, that portrays the full Lost Wax Casting scheme here.