Bone china is a luxurious and durable material that people have used for dinnerware for centuries.
But how is bone china made? It goes through a long journey from raw materials to taking our dining tables.
This article will explore the manufacturing process and the craftsmanship used to create bone china.
A Brief History of Bone China
Bone china originated in England during the 18th century. It became popular due to its strength, translucency, and whiteness.
While English factories dominated production until the mid-20th century, other countries, such as Japan and Thailand, began producing bone china.
Today, bone china remains a popular material for tableware due to its elegance and durability.
How is Bone China Made?
The manufacturing process of bone china includes main steps: clay making, forming, glazing, decorating, firing three times, and packaging.
1. Clay Making
The first step in manufacturing bone china is to mix the raw materials to make bone china clay.
Manufacturers mix bone ash, feldspar, kaolin, and water in precise proportions. The materials’ proportions may vary depending on the intended uses. However, bone ash is typically the most significant component.
Then the mixing process is done in a grinding mill. The grinding stage usually lasts about 24 hours.
At the end of the stage, the manufacturers receive the slurry. The slurry then runs through a special device to remove iron as well as other impurities.
After that, manufacturers will take away water and air from the mixture by pumping it into a filter press. This device reduces the level of moisture to around 20%. The process repeats 3 or 4 times to create the slip.
Next, a large slicer involves cutting the slip into many clay blocks for the next usage.
Artisans shape the clay into the desired form through either casting or jiggering.
In general, they usually use jiggers to form round pieces like plates or bowls. As for items with more complex shapes, such as teapots and vases, they usually apply the casting method.
3. Biscuit Firing (First Firing)
After the piece has dried, artisans put it in a kiln. Unlike other types of porcelain, people often fire bone china with higher temperatures, approximately 1,200 to over 1,300°C. The firing process often takes more than 15 hours.
Yet, high temperatures also increase the chance of cracking or deformation. So, people place most items in setters to keep them in the desired shape.
They call the final product of this step biscuit ware. After taking the biscuit ware out of the kiln, artisans give them a bath. They use water and smooth stones to polish the items’ rough outside.
Next, they use an industrial dishwasher before a dryer to wash and dry the ware after the stone bath.
Then, an inspector closely checks each item for damage or flaws. If the pieces pass inspection, artisans will bring them to the glazing stage.
Together with the bone ash proportion, the glaze makes bone china more durable than other types of porcelain. This glaze acts as a protective layer on the biscuit and gives the final product a shiny appearance.
Artisans mix bone ash plus kaolin to create the glaze for bone china to protect the biscuit better. As the biscuit hardly absorbs the glaze, they have to apply the glaze by spraying. In this process, they can hand dip or use machines.
Once finished glazing, artisans must wipe the bottom of each bone china piece with a wet sponge to prevent it from dirtying the kiln.
5. Glost Firing (Second Firing)
After waiting for the glaze to dry, they place the items in the glazing firing kiln and fire them for more than 7 hours with temperatures of 1,080°C for the second time.
Artisans place the glazed biscuits in devices called saggers to prevent them from exposing directly to flames.
Once the temperature rises to approximately 1,000°C – 1,200°C, the glaze turns to liquid so the biscuits can absorb it.
Once biscuit wares have cooled down, they go under inspection. Just a few pieces pass the inspection and are ready for decorating.
Artisans use several decorating methods in bone china production. Those methods can be spraying, hand painting, and decal application. Of these, the most widespread method used is decal application.
They can either apply decals manually or by machine. If hand-applying the decal, they must first clean the items. Dust could impact the decal’s effectiveness and decrease the final product’s appearance.
Much like decal application, artisans must apply platinum, gold, or other precious metal to the item by hand.
7. Decoration Firing (Third Firing)
When the artisans finish the decoration process, the products go through one final firing at a slightly lower temperature, around 700°C to 800°C.
This final firing will ensure that the decoration becomes permanent and gives bone china its unique strength, translucency, and whiteness.
After completing the decoration process, artisans thoroughly inspect the bone china products and carefully package them for transport.
Uses of Bone China
Bone china is an ideal choice for various uses, from everyday tableware to decorative and gift items.
People use bone china to make elegant, high-quality dinnerware and tea sets. Bone china’s lightweight, durable, and delicate nature makes it ideal for serving hot meals or beverages.
Another use of bone china is to create decorative objects like figurines, vases, and other items. People can display them in homes or give them as gifts.
How to Take Care of Your Bone China?
Taking care of bone china is vital to maintain its beauty and durability. Let’s check some following tips:
Hand-wash your bone china: Don’t put your bone china in the dishwasher. Instead, you should wash your bone china by hand. You should also use mild dish soap and warm water.
Store carefully: When storing your bone china, use felt or cloth protectors between each piece to prevent scratches or chips.
Avoid extreme temperatures: Bone china can crack or break under extreme temperatures, so avoid placing it in the freezer or microwave.
Creating bone china is fascinating and requires a combination of science and art.
From the mixing of raw materials to the final firing of the product, every step requires precision and attention to detail.
So by understanding how it’s made, we can better appreciate the artistry and skill that goes into making this luxurious material.