Creating a realistic and finely detailed bronze sculpture begins with extensive research, starting with a collection of numerous photos of the subject for reference purposes

Extra special consideration is given to photos that capture the facial expression both the the artist & commissioner wish to immortalise, in the final sculpture

By meticulously studying and selecting these photos, the artist can craft a lifelike and meaningful sculpture in bronze, that faithfully represents the subject

If necessary, a sketch may be produced and presented to the customer for confirmation that this is indeed, an accurate representation of the finished bronze, they have in mind

An artist creates a model using materials such as wax, clay or other oil-based substances, that remain soft and workable

We at Escar UK Bronze prefer to use modelling wax as there is no need to fabricate an armature (a framework that supports a sculpture when it can’t stand on its own), as is required with clay

By using various pre-made modelling waxes, the artist has the luxury to customise the hardness of the material according to the project’s needs, simply by mixing various types of waxes and using additives

Also waxes sensitivity to temperature is also a major advantage over clay, as different waxes behave differently, at differing temperatures

When cold, modeling wax is hard & rigid and suitable for carving, when warm, it becomes soft and pliable, which is ideal for shaping and moulding

It can also be heated in a pot and painted on with a brush to create thin layers, or when slightly cooled, applied with a spatula or knife, if thicker layers are required

When completely cool, wax is able to capture a higher level of detail, that unfortunately, is difficult to obtain with clay

Allowing wax to cool and harden between sessions means a modeling project can be paused and later resumed, without drying out like clay. This feature is particularly useful when awaiting feedback on a commissioned sculpture

Another huge advantage of modelling wax against clay is that it can be reused almost indefinitely and if well looked after, is an ideal substrate to rework a concept, many times over

And last but not least, modelling wax can be added or removed with ease

A mould of two shell-like halves is made from the original wax model, with each having two layers, one inner and one outer

The inner layer is normally created by painting layers of latex or silicone onto the wax model to a defined thickness, which perfectly captures the fine detail the artist has imparted into the wax and left to dry

The outer layer is commonly made from plaster or fibreglass, to support and protect the soft mould within

During this process, flanges with built-in male to female register pegs are added on the outside around the middle. This is to facilitate split the inner and outer shell into two halves when cured and more importantly, to ensure the two halves match up perfectly when re-assembled

Holes may also be  drilled around the flange if necessary, to allow the two halves to be bolted together to prevent any movement after they have been carefully aligned

When cured, the moulds are then carefully separated to produce two halves, and removed from the artist’s wax

The two halves are then carefully re-assembled to become a whole and molten wax is poured inside and swirled around to allow an even layer to coat the inner surface

Every artist is different however, and will have found their own preferred quantities of wax, to make their ideal cast

In large castings, this is done as many times as is necessary until the required thickness is achieved, normally around 3mm

It is then allowed to cool, or force cooled with cold water as in this video, resulting in a hard hollow wax positive copy of the mould it came out of

Once the wax is set, the mould is then removed from wax positive and used again if it is a batch order

When the order is completed, the two halves are put into storage for making future duplicates

For this small Buddha casting, a hole is scooped out of a pile of sand, the positive placed into it upside down and sand carefully compacted around it for support

Then a silica slurry is hand mixed from powder and water, and a scoop of sand added to give it extra strength. This is then poured into the inverted wax positive and left to set

Once the ceramic slurry has set, the wax positive is removed from the sand and now forms the inner half of the mould

The positive copy is then “Chased” on the outside if necessary, to remove any imperfections

Chasing is where a heated metal tool is used to smooth out and hide any imperfections in the wax positive and to remove the line that is produced by using a mould of two halves

In larger castings, ‘Spruing the Wax’ is where wax is rolled into long solid cylindrical shapes and added to the outside of the wax model

This is done to create hollow tunnels through which the molten wax can run out, and once done, leave behind hollow tubes which act as airways for air to escape, as the molten bronze is poured in

Here in this video we see a series of images of wax positives covered in slurry and allowed to set, then bound with wire and more slurry applied to cover the wire until a strong, solid mould is created

Further images show examples of various other  moulds

The final four images show the mould split (including damage to the silicone mould), and the final cast and finished bronze Buddhas, one raw, and the other chemically patinated

The sprued wax model is then covered in slurry of silica and sand stucco inside and out, similar to the small castings only on a larger scale

The combination of these two materials is known as the Inner and Outer Ceramic Shell Moulds

This process is repeated until half an inch of Ceramic Shell Mould coats the wax mould, which is then bound with wire to give it strength

Once the ceramic outer is hard, metal pins are hammered into the outer shell, on though the wax and into the inner core, to keep the inner and outer moulds in alignment once the wax is melted and poured away

Before the molten bronze is added, the mould will first be inspected for any weak points or holes, where leaks may occur

Any damage can then be repaired, holes patched and should they be required, additional holes drilled to aid draining

For a large casting like this full-sized Gorilla, holes are made around the base and plugged with wax

Once the kiln is built around the moulds and fired, the wax will melt and run out. This will be consumed as fuel for the fire and be burnt

First, large slow burning logs are set under and around the moulds

Then the kiln will be build around the moulds using breeze blocks and a metal roof added above, to contain the heat within

Kindling wood is then placed in the space between the logs and the inner walls of the kiln

This is then fired and tended as required

The fuel is left to slow burn overnight, so the moulds are brought up to temperature to prevent the hot molten metal from cracking them, when it is poured in the following day

The bronze casting process begins with melting the bronze metal in a furnace, which reaches approximately 1200°C to achieve a molten state

It is then brought up to temperature, inverted to allow the molten wax inside to drain from the bottom through the sprued vents & tunnels, leaving a hollow space between the inner and outer ceramic moulds, for casting with molten bronze

The molten bronze is then transferred to a crucible, both for safety and ease of transport, and poured into the pre-heated mould. 

 

Once the mould is filled with the required amount of molten bronze, it is then left to cool and solidify

 

This careful control of temperature and gradual cooling ensures the final cast maintains its desired shape and structural integrity

The process  highlights the importance of temperature management in metal casting, not only to prevent damage but to also to ensure a high-quality final product

It is at this stage our process gets it’s name, ‘The Lost Wax Bronze Casting Process’

When cool, the bronze casting is released by drilling away the inner core, hammering away the outer shell and removing the sprues

The sprues will be melted down and used again but the ceramic shell is lost

Bronze metal chasing is employed, the same as with wax chasing, to remove all signs of casting

Imperfections or pits from air bubbles can be removed by filling the surface and refinishing and where the sculpture has been cast in several pieces, these are welded together and re-finished

Finally we have bronze cast of the original sculpted model, which is then prepared for Patination

The original cast that has been broken out of the plaster mould, the larger it is, the rougher it usually turns out. So there is a long way to go, before the raw cast bronze, is ready for patination

This involves welding bronze metal into parts that didn’t get cast due to various reasons, (trapped air/moisture etc.) Grinding off rough pieces of bronze, that got cast into any gaps in the two halves of the moulds, and any other surface imperfections that are present

The next stage is to add the fine features like fur or feathers, using grinders and Dremel tools, equipped with various sizes of grinding bits, suitable for the job

If the bronze is too large to be cast in one piece, any additional pieces that were moulded separately would also be added at this point

Finally we have a finished bronze cast of the original sculpted model, which is then prepared for Patination

This is the art of colouring  the sculpture using various chemicals, different combinations of which, create various colours

Once patinated, the sculpture is then protected with layers of wax applied under heat, followed by two cold applications and then buffed to reach a fine lustre

The sculpture is then protected with layers of wax applied under heat, followed by two cold applications and then buffed to reach a fine lustre

Overtime and after repeated use, the definition will be reduced and a new mould will need to be fashioned

Also because of the fragile nature of silicon, sometimes the inner moulds get damaged

This is something we keep a close eye on to ensure that our current moulds produce a finely detailed firing wax, to the quality of the original

If degradation occurs, the current wax is returned to the artist, the lost details reinstated, new moulds are created and the old moulds are scrapped

As can be seen from the narrative above, the Art of Bronze is a very hands-on process that goes through many stages, before the final sculpture is ready for delivery to the customer

We do hope the information contained within has been informative, and we look forward to making your acquaintance sometime in the near future 

Escar UK Bronze