Keum Boo, and other gold plating
Keum Boo is a traditional Korean method of adding a thin gold layer to another metal.
Keum Boo: What is it?
Keum boo is a beautiful and ancient technique, and it's understandable that you'd want to know more about it. Here's a breakdown:
History of Keum Boo:
Ancient Korean Origins:
Keum boo (also spelled kum-boo or kum-bu) is a traditional Korean technique that translates to "attached gold."
It involves bonding thin sheets of 24k gold to silver.
While its origins are firmly rooted in Korea, similar gilding techniques have been found in other ancient cultures.
Cultural Significance:
It has been used to create decorative items, jewelry, and other precious objects.
The technique reflects the artistry and skill of ancient Korean metalworkers.
Modern Revival:
Today, keum boo is experiencing a revival among contemporary jewelers and metalsmiths who appreciate its unique aesthetic.
Overview of How to Do Keum Boo:
Preparation:
The silver surface is often "depletion gilded" to bring a layer of fine silver to the surface. This creates a better bonding surface for the gold.
24k gold foil is used.
Bonding:
The silver is heated to a specific temperature.
The gold foil is placed onto the heated silver.
Pressure is applied using a burnisher, which creates a diffusion bond between the gold and silver.
Key Factors:
Temperature control is crucial.
Cleanliness of the metals is essential for a good bond.
Pressure is necessary to facilitate the bonding process.
There are many types of gold plating. Let’s go over them!
Differences Between Keum Boo, Vermeil, Electroplating, and Clad:
Keum Boo:
A process of diffusion bonding gold foil to silver using heat and pressure.
Creates a relatively thick layer of gold.
A mechanical bonding process.
Vermeil:
Sterling silver that is gold-plated.
Requires a minimum gold thickness.
An electroplating process.
Electroplating:
A process of depositing a thin layer of metal onto a conductive surface using an electric current.
Can be used to apply various metals, including gold, to different base metals.
Generally creates a very thin layer of the plating metal.
Clad:
A process of bonding two or more layers of different metals together.
Often involves rolling or pressing the metals together under high pressure.
Creates a layered material.
Reticulated (Silver)
Reticulation is a method of creating a wrinkly texture on metal, typically silver, using depletion gilding.
Reticulation: What is it?
Reticulated silver is a fascinating metalworking technique that creates a unique, rippled, and textured surface. Here's a breakdown of its history and how it's done:
History:
Late 19th Century Origins:
The technique gained prominence in the late 19th century, particularly in Czarist Russia.
It was notably used by Russian goldsmiths, including those working for Fabergé, where it was sometimes referred to as "samorodok," meaning "born by itself."
From Russia, the technique spread to Scandinavian countries.
Scandinavian Influence:
Finnish metalsmiths played a significant role in developing and popularizing reticulation.
After the closure of the Fabergé studios during the Russian Revolution, these Finnish artisans brought the technique back to their homeland.
Heikki Seppa, a renowned Finnish metalsmith, is credited with helping to introduce and popularize reticulation in North America.
Modern Practice:
Today, reticulation is primarily used by studio jewelers and metalsmiths to create distinctive and artistic pieces.
Overview of the Process:
Reticulation relies on the differing melting points of the metals within a silver alloy, typically silver and copper. Here's a simplified overview:
Depletion Gilding:
The process often begins with "depletion gilding." This involves repeatedly heating the silver alloy and then pickling it.
Heating oxidizes the copper on the surface, and pickling removes the copper oxide.
This process results in a surface layer that is richer in fine silver, which has a higher melting point than the underlying alloy.
Heating and Reticulation:
The metal is then heated with a torch.
Because of the difference in melting points, the inner alloy begins to melt before the fine silver surface.
This creates the characteristic rippled or wrinkled texture as the molten inner alloy moves and the surface layer constrains it.
Factors Influencing the Texture:
The specific alloy composition, the number of heating and pickling cycles, and the torch technique all influence the final texture.
Different silver-copper ratios will produce different results.
Safety considerations:
This process uses a torch, and pickling solution, thus adequate safety precautions must be taken.
Key Points:
Reticulation produces unique, one-of-a-kind textures.
It relies on the controlled application of heat and the properties of metal alloys.
It's a technique that requires practice and skill to master.
Slip Casting
Slip Casting is a way ceramic method used to create a variety of works from intricate sculptures to mass production porcelain sinks.
Slip Cast Ceramic: What is it?
Slip casting is a ceramic forming technique that allows for the creation of intricate and consistent ceramic pieces. Here's a quick overview:
History:
Ancient Roots:
While its widespread use came later, the foundation of the technique can be traced back to ancient civilizations in places like Egypt, Mesopotamia, and China.
Early forms of molding with clay slips were employed.
Development:
It is noted that development of the slip casting methods we know today came to fruition in China during the Tang Dynasty.
The technique gained significant traction during the Industrial Revolution in Europe, particularly in the 18th and 19th centuries.
The use of plaster molds and the desire for mass production greatly accelerated its adoption.
Traditional Uses:
Figurines: Creating detailed ceramic figures.
Tableware: Producing matching sets of cups, plates, and bowls.
Sanitary Ware: Forming toilets and sinks.
Decorative Items: Crafting intricate ornaments and vessels.
Modern Applications:
Industrial Ceramics: Manufacturing technical ceramics for various industries.
Art and Design: Creating contemporary ceramic sculptures and design objects.
Medical Ceramics: Producing medical implants and prosthetics.
Mass Production: Continued use in producing consistent tableware and sanitary ware.
How to Make Slip Cast Molds:
Creating the Master:
Begin with a model of the desired object. This "master" can be made from clay, wood, or other materials.
Mold Preparation:
The master is then placed within a container, and plaster is poured around it.
Multi-part molds are used for complex shapes, requiring careful planning and division of the mold.
Plaster Setting:
The plaster hardens, creating a negative impression of the master.
Mold Separation:
The mold is carefully separated from the master.
Mold Preparation for slip:
Once the master is removed, the inside of the plaster mold will receive the slip.
Slip Casting:
The clay slip is poured into the plaster mold.
The plaster absorbs water from the slip, causing a layer of clay to form against the mold walls.
Excess slip is poured out, and the clay form is allowed to dry.
The finished ceramic piece is then removed from the mold.
Key points about plaster molds.
Plaster's porosity is crucial, as it draws water from the slip.
Multi-part molds enable the creation of complex three-dimensional forms.
Lost Wax Casting
Lost Wax Casting is an ancient method of creating intricate designs with a shapable, combustable material such as bees wax to create a mold for a less malleable material such as bronze.
Lost wax casting: What is it?
Lost-wax casting, also known as investment casting, is a very old and versatile metal-forming technique. Here's a quick rundown:
History:
Ancient Origins:
The technique dates back thousands of years, with evidence of its use as early as the 4th millennium BC.
Early examples have been found in various regions, including the Middle East, the Indus Valley, and Europe.
It was used to create intricate objects in copper, bronze, gold, and other metals.
Development:
The technique was refined over centuries, with advancements in mold materials and casting methods.
Significant advancements occurred during the renaissance, and then again in the early 20th century.
The introduction of rubber molds, and centrifugal casting machines greatly improved the process.
Traditional Uses:
Sculpture: Creating detailed bronze statues and other sculptural works.
Jewelry: Crafting intricate jewelry pieces.
Religious Objects: Producing religious icons and artifacts.
Tools and Weapons: Forming early metal tools and weapons.
Modern Applications:
Aerospace: Manufacturing precision parts for aircraft and spacecraft.
Medical: Creating medical implants and prosthetics.
Automotive: Producing complex engine components.
Art and Jewelry: Continuing to be used for fine art and jewelry making.
Industrial Components: creating a wide variety of precision metal parts.
Mold Making from Wax Prototypes:
The core of lost-wax casting is creating a wax prototype of the desired object.
This wax model is then encased in a mold material (like ceramic).
The mold is heated, melting and "losing" the wax, leaving a cavity.
Molten metal is poured into the cavity, and once cooled, the mold is broken away, revealing the metal casting.
The key difference in mold making from wax prototypes, is that the wax is intentionally removed, to create the void that the molten metal will fill.
Essentially, lost-wax casting allows for the creation of highly detailed and complex metal objects that would be difficult or impossible to produce with other methods.