Pottery maker Charles Walter Clewell was born in Canton, Ohio in 1876. He attended Ohio Northern University, where he studied mathematics and chemistry. He worked as a machinist and toolmaker at Dueber-Hampden, and during World War II he made precision gauges at The Timken Company.
But Clewell is most remembered for his unique bronzework pottery, created by a closely-guarded secret process that he shared with no one.
What is Bronze?
Clewell worked in bronze, which is an alloy of copper and tin that has been used for thousands of years. In the prehistoric period known as the Bronze Age (3300-1200 BC), societies first began to use advanced metalworking techniques by melting copper and tin together.
The molten metal alloy was then cast into many different kinds of artifacts, ranging from sword blades to decorative trinkets. It was these prehistoric artifacts that inspired Clewell.
Discovering the Bronze Patina
Clewell was part craftsman, part artisan, part chemist, and part artist. His interest in bronze began around 1900 when he noticed a large copper heating tank that had been cleaned with a chemical solution. Apparently the chemicals had not been entirely removed. A cloud of green formed which seemed to be gradually covering the surface of the vessel. He was fascinated by the way the corrosion seemed to climb over the tank.
In a 1949 article in The Repository (Canton, Ohio), Clewell described that first encounter: “It was not a solid color nor of even intensity, and in some places the bare metal appeared, tarnished and gleaming or almost black, in contrast with the green which slowly was hiding it.”
He decided that its beauty was not in the final patina, but in the transition from bright metal tones to blue and blue-green shades as the metal corroded.
Clewell decided to try to replicate this process on vases and other decorative pieces. The exact process for creating the patina itself is not known. Clewell never shared it with anyone and took it to his grave.
How Clewell Made Pottery
Here’s what we know about the process:
- He started with bisque pottery blanks, purchased from nearby potteries in northeast Ohio.
- Using an electrolytic process, he coated each piece in a thin layer of bronze by dipping the pottery in a solution into which copper salts were suspended. The copper salts coated the surface of the pottery, creating a copper “shell” on the exterior of the piece.
- Next, he applied a secret blend of chemicals that started the controlled corrosion process. Clewell was able to replicate a process in a few weeks that usually took nature years to achieve. This process actually altered the patina of the bronze, rather than applying ornamentation of any kind.
- Finally, he stopped the chemical process when the desired effect was achieved. The “desired effect” is where the artist’s eye comes in. Clewell told the Repository, “To me, it seems that in these unexpected variations lies the great charm of bronze, for frostwork, fleecy clouds and imaginary landscapes may appear.”
Finding Inspiration in Ancient Copper
Clewell spent his life searching for color in bronze, which took him to many places throughout the country. The blue-bronze for which he is most known is quite rare in nature.
Early on he visited the Wadsworth Athenaeum in Hartford, CT and saw a small bronze wine jug in the J. Pierpont Morgan Memorial Collection. It had been found during an archeological excavation in Italy and was dated about 200 BC.
It was blue, with varying tones from turquoise to almost black, with flecks of green and rust-like brown, and some areas of bare, darkened metal. He knew that the reaction must have been caused by certain chemicals in the soil, and that if he could find the right combination, he could reproduce the same effect.
“Seeing that little jug cost me more than two years of experimenting,” Clewell told the Repository, “and a number of trips to Hartford to compare results, but finally the perfect blue appeared. It was a long hunt and particularly difficult; textbooks gave me no help.”
Today Clewell's bronzework is rare and unique, and quite prized among collectors.
For more information on Clewell pottery:
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