Metal clay
Encyclopedia
Metal clay is a crafting medium consisting of very small particles of metal such as silver
, gold
, platinum
, or copper
mixed with an organic binder and water for use in making jewelry, bead
s and small sculptures. Originating in Japan in 1990, metal clay can be shaped just like any soft clay
, by hand or using molds. After drying, the clay can be fired in a variety of ways such as in a kiln
, with a handheld gas torch, or on a gas stove. The binder burns away, leaving the pure sintered
metal. Shrinkage of between 8% and 30% occurs (depending on the product used). Alloys such as bronze
or steel
also are available.
used to form a precious metal article, the material consists of microscopic particles of pure silver or fine gold powder and a water-soluble, non-toxic, organic binder that burns off during firing. Success was first achieved with gold and later duplicated with silver.
The PMC brand includes the following products:
Further developments introduced the Art Clay Slow Dry, a clay with a longer working time. Art Clay 650 and Art Clay 650 Slow Dry soon followed; both clays can be fired at 650 °C (1,202 °F), allowing the user to combine the clay with glass and sterling silver, which are affected negatively by the higher temperatures needed to fire the first generation clays. AIDA also manufacturers Oil Paste, a product used only on fired metal clay or milled fine silver, and Overlay Paste, which is designed for drawing designs on glass and porcelain.
In 2006 AIDA introduced the Art Clay Gold Paste, a more economical way to work with gold. The paste is painted onto the fired silver clay, then refired in a kiln, or with a torch or gas stove. When fired, it bonds with the silver, giving a 22ct gold accent. The same year also saw Art Clay Slow Tarnish introduced, a clay that tarnishes less rapidly than the other metal clays.
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...
, gold
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...
, platinum
Platinum
Platinum is a chemical element with the chemical symbol Pt and an atomic number of 78. Its name is derived from the Spanish term platina del Pinto, which is literally translated into "little silver of the Pinto River." It is a dense, malleable, ductile, precious, gray-white transition metal...
, or copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
mixed with an organic binder and water for use in making jewelry, bead
Bead
A bead is a small, decorative object that is usually pierced for threading or stringing. Beads range in size from under to over in diameter. A pair of beads made from Nassarius sea snail shells, approximately 100,000 years old, are thought to be the earliest known examples of jewellery. Beadwork...
s and small sculptures. Originating in Japan in 1990, metal clay can be shaped just like any soft clay
Modelling clay
You can use modelling clay to create items with it. The material compositions and production processes vary considerably. -Ceramic clay:...
, by hand or using molds. After drying, the clay can be fired in a variety of ways such as in a kiln
Kiln
A kiln is a thermally insulated chamber, or oven, in which a controlled temperature regime is produced. Uses include the hardening, burning or drying of materials...
, with a handheld gas torch, or on a gas stove. The binder burns away, leaving the pure sintered
Sintering
Sintering is a method used to create objects from powders. It is based on atomic diffusion. Diffusion occurs in any material above absolute zero, but it occurs much faster at higher temperatures. In most sintering processes, the powdered material is held in a mold and then heated to a temperature...
metal. Shrinkage of between 8% and 30% occurs (depending on the product used). Alloys such as bronze
Bronze
Bronze is a metal alloy consisting primarily of copper, usually with tin as the main additive. It is hard and brittle, and it was particularly significant in antiquity, so much so that the Bronze Age was named after the metal...
or steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
also are available.
History
Metal clay first came out in Japan in 1990 to allow craft jewelry makers to make sophisticated looking jewelry without the years of study needed to make fine jewelry.Silver metal clay
Silver metal clay results in objects containing 99.9% pure silver, which is suitable for enameling. Although gold metal clay is more expensive, it provides richer color. Lump metal clay is sold in sealed packets to keep it moist and workable. The silver versions are also available as a softer paste in a pre-filled syringe which can be used to produce extruded forms, in small jars of slip and as paper-like sheets, from which most of the moisture has been removed. Common brands of silver metal clay include Precious Metal Clay (PMC) and Art Clay Silver (ACS).Precious Metal Clay (PMC)
PMC was developed in the early 1990s in Japan by metallurgist Masaki Morikawa. As a solid-phase sintered product of a precious metal powderPowder metallurgy
Powder metallurgy is the process of blending fine powdered materials, pressing them into a desired shape , and then heating the compressed material in a controlled atmosphere to bond the material . The powder metallurgy process generally consists of four basic steps: powder manufacture, powder...
used to form a precious metal article, the material consists of microscopic particles of pure silver or fine gold powder and a water-soluble, non-toxic, organic binder that burns off during firing. Success was first achieved with gold and later duplicated with silver.
The PMC brand includes the following products:
- The original formula of PMC, now called "standard": fired at 900 °C (1,652 °F) for 2 hours, shrinks by 30% during firing.
- PMC+: fired at 900 °C (1,652 °F) for 10 minutes or 800 °C (1,472 °F) for 30 minutes; shrinks 15%, due to a particle size reduction. PMC+ is also available in sheet form which can be worked like paper; for example, for origamiOrigamiis the traditional Japanese art of paper folding, which started in the 17th century AD at the latest and was popularized outside Japan in the mid-1900s. It has since then evolved into a modern art form...
. - PMC3: fired at 599 °C (1,110.2 °F) for 45 minutes or 699 °C (1,290.2 °F) for 10 minutes; shrinks by 10%. It can also be fired using a butane torchButane torchA butane torch is a tool which creates an intensely hot flame using butane, a flammable gas.Consumer air butane torches are often claimed to develop flame temperatures up to approximately...
by heating it to orange heat for at least 2 minutes. It has a longer working life than the older formulations. It is also available in slip and paste forms which can be painted onto the surface of an object to be used as a mould. - Aura 22: a 22 kCarat (purity)The karat or carat is a unit of purity for gold alloys.- Measure :Karat purity is measured as 24 times the purity by mass:where...
gildingGildingThe term gilding covers a number of decorative techniques for applying fine gold leaf or powder to solid surfaces such as wood, stone, or metal to give a thin coating of gold. A gilded object is described as "gilt"...
material, a gold paste intended to be painted onto the surface of silver PMC pieces, or ready-made silver objects. - PMC Pro: a harder product which is only 0.900 silver, hence it canot be hallmarkedSilver hallmarksA sterling silver object that is to be sold commercially is, in most countries, stamped with one or more silver hallmarks indicating the purity of the silver, the mark of the manufacturer or silversmith, and other markings to indicate date of manufacture and additional information about the piece...
as sterling silverSterling silverSterling silver is an alloy of silver containing 92.5% by mass of silver and 7.5% by mass of other metals, usually copper. The sterling silver standard has a minimum millesimal fineness of 925....
. It also requires kiln firing in a tub of activated carbonActivated carbonActivated carbon, also called activated charcoal, activated coal or carbo activatus, is a form of carbon that has been processed to make it extremely porous and thus to have a very large surface area available for adsorption or chemical reactions.The word activated in the name is sometimes replaced...
for 1 hours at 760 °C (1,400 °F).
Art Clay Silver (ACS)
ACS was developed by AIDA Chemical Industries, also a Japanese company. ACS followed PMC Standard with their Art Clay Original clay (more like PMC+ than PMC Standard), which allows the user to fire with a handheld torch or on a gas hob. Owing to subtle differences in the binder and suggested firing times, this clay shrinks less than the PMC versions, approximately 8–10%.Further developments introduced the Art Clay Slow Dry, a clay with a longer working time. Art Clay 650 and Art Clay 650 Slow Dry soon followed; both clays can be fired at 650 °C (1,202 °F), allowing the user to combine the clay with glass and sterling silver, which are affected negatively by the higher temperatures needed to fire the first generation clays. AIDA also manufacturers Oil Paste, a product used only on fired metal clay or milled fine silver, and Overlay Paste, which is designed for drawing designs on glass and porcelain.
In 2006 AIDA introduced the Art Clay Gold Paste, a more economical way to work with gold. The paste is painted onto the fired silver clay, then refired in a kiln, or with a torch or gas stove. When fired, it bonds with the silver, giving a 22ct gold accent. The same year also saw Art Clay Slow Tarnish introduced, a clay that tarnishes less rapidly than the other metal clays.