Lost Wax Casting Process: How a 10th century technology has adapted itself to modern manufacturing... with limitations

https://youtu.be/XTjmiAo8YJQ

Video of lost wax casting done similarly to what was done in the 10th century.

10th Chola bronze idols are some of the most valuable treasures in the art world. Valued at ten of thousands of dollars.?

The process of making these idols is NOT a lost art, atleast among the artisans of southern India. Attached is a video of one such artisan demonstrating how a Chola bronze is made and would have been made in the 10th century.?

The precision of the ancient Chola idols is something to behold. Mind you, sand casting can never capture the intricacies of these idols. What follows after the casting is a cold chiseling process which is not shown in the video. The cold chiseling in these Chola idols is breathtaking especially if you see some of the "non-chiseled" bronzes from the 10th Century. Vidya Dehejia in her book on Chola bronzes describes one of these and the difference is striking. The skill of the sculptor must have been other worldly.

More important, to atleast the mechanical designers amongst us, is the measurement system used then. There was no SI units or any of the western methods which occupy our engineering textbooks today.?The Greeks had used the method of proportions when making their masterpieces. We used something similar called Silpa Shastra, texts of these are available even today. Not sure about the quality or accuracy as a lot might have been lost in translation over the centuries.?

Now how has this casting technique adapted itself to current eras or has it adapted at all??

How about the most important factor in the process? The design. Can any modern manufacturing method capture the intricacies of the 10th century bronze. Even with a multi axis CNC system combined with metal casting the complexity would be too much. The answer lies in 3d printing. The only way to capture the sculptor's complex chisel movements is to print the wax statue layer by layer at high accuracy in a good 3d printer. The constraints of the 3d printing process remain i.e. support on heavier sides, thickness of the highly intricate areas , etc. However these constraints would be there for any complex printed part and, more importantly, are part of the 10th century process also.?

The materials chosen during the 10th century (beeswax, etc), other than their obvious chemical properties of melting points and viscosity, were due to their ease of availability. Fortunately there are a lot of wax products readily available for 3d printers exactly for this purposes. A simple Google search shows up a lot of good quality materials.?

But coming back to the wax model design, the skill of sculptor is replaced by the skill of the 3d designer. The CAD file would still have to be designed manually using modern measurement systems. Not an easy job if you could study the statues intricate areas like fingers, hair, etc. So the importance of human skill quality remains, even after 10 centuries, though the medium has changed.

The next area of high skill is the cold chiseling process. The modern casting technique can ensure a lot of the intricacies, which were cold chiseled in the 10th century, are part of the casting itself due to advancements in mold materials, etc. However it would still need a highly skilled artisan to finish the bronze statue in all its glory else it would be a design limited by the manufacturing process of this era (what an irony that would be). The thickness, surface finish, etc of the intricate areas as required in the finished product would be impossible in the raw cast. Hence the need of human intervention.

So can we conclusively say that this ancient technology has completely undergone a shift towards modern manufacturing techniques. Definitely no. There are still areas which need the involvement of a skilled designer or sculptor. These skills remain exactly the same as they were 10 centuries ago. However the danger remains in loosing these artisans, measurement techniques, etc if their skills are not updated and modern engineering institutions don't make an effort to study and record these techniques in high detail and ensure these are passed down generations.