Our methods
The lost wax process
To produce a bronze sculpture, we use a process called 'the lost wax process'. This involves a number of processes all as important as one another to ensure we achieve a high-end product that meets our customers' expectations.
Mould making
Mould making is a highly skilled and time-sensitive process whereby we cover the entire original work in silicone, creating a negative imprint of the work to fingerprint detail and quality. Once the silicone has cured, it is covered with a fibreglass jacket to ensure the mould's rigidity, otherwise once removed, the rubber would become unstable and not give a true representation of the work.
Wax casting
Once the silicone mould is completed, it's handed over to our wax team who proceed to brush in hot wax to the mould, giving us a thickness of 5-8mm. This will determine the thickness of the bronze once cast. Once the wax has cooled and is ready to be removed from the mould, the wax fettling stage gets underway (cleaning up seams) using a variety of sculpting tools, white spirit, and a Bunsen burner.
The final wax pattern is then tree'd up using wax runners and risers in preparation for the ceramic shell investment. This creates channels, so when the wax is burnt out, you are left with hollow channels for the bronze to flow freely into, allowing it to get exactly where it needs to be.
Ceramic shell making
Our ceramic shell room can be messy, noisy, and smelly, but it's very much an essential part of the Foundry and the bronze casting process. We dip the wax up to 12 times into our ceramic slurry, depending on the size of the piece or section. In between each layer of slurry, we coat it in fused silica which gives us our thickness in the shell, ready for the burn out.
Once our shells are ready, we need to burn the wax out. We prep the shells by removing the bottom of the cup and cutting air vents in the runners. We then place the shells inside of the kiln and heat them up to around 800-900 °C until the wax has been removed and the cup has burnt away. This gives us the perfect shells ready for casting.
Bronze pouring
Now our shells are ready for pouring, first things first we need to melt our bronze. Whilst the shells are cooking in the kiln at around 800°C, we fire up the furnace to a scorching 1100°C and begin to melt our bronze ingots. Once our molten bronze is up to temperature, we remove the shells from the kiln and place them into the sand pit and submerge them up to the pouring cup. This gives the shells stability during the pour. Now we're ready, we lift the crucible of molten bronze out of the furnace into the pouring shank, and then comes the satisfying process of filling those shells up.
Metal work
Now our shells are poured, we smash and remove the shell from the cast bronze piece and begin cleaning them up. Using angle grinders and chisels, we remove the runners and risers, then they're off to the sandblaster, where the piece is given an overall clean to remove any remaining ceramic shell. The piece then gets into the hands of the metalworkers, who carry out the highly skilled process of chasing and fettling all of the fine details back into the work to match the original artwork.
For larger sculptures during this stage, we also TIG weld any sections of bronze together where required that were too large to pour in one piece. This is a highly skilled job and takes years of resilience and hard work to perfect the craft, but well worth the years of practice, as the end quality is seamless.
Patination
Once the metalwork is completed, the piece then makes its way over to the patination station, where it finds itself at the end of its foundry journey, but at the beginning of its new life as a beautifully crafted piece of work to be enjoyed by all. From the raw bronze to the final wax, the patinator uses a variety of chemicals and dioxides to apply the desired finish, which can range from a traditional bronze to a more creative approach. The patinator has one of the most important responsibilities of the entire process, as they have to ensure they get the colour perfect to reach the client's vision.
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