Platinum Jewelry Casting Services from International Mfg. Co.
The platinum casting services offered by the team of experts at international Mfg. Co. will assist you in creating exceptional quality platinum jewelry on time and on budget.
The History of Platinum use in Jewelry .
Platinum is one of the rarest and most durable precious metals. Platinum’s rich, white luster enhances the brilliance and will maintain its shining luminosity forever, unlike other white metals which can, in time, tarnish.
Platinum is a member of a group of metals named after itself. Other platinum metals include ruthenium, rhodium, palladium, osmium, and indium. The platinum group metals are sometimes referred to as the noble metals. That term comes from the fact that they are all relatively inactive. They do not combine with or interact with most other elements or compounds. These factors, along with its strength and white luster, have made platinum an increasingly popular choice for jewelry, either on its own or as the setting for diamonds and other precious gemstones. Platinum’s purity makes it hypoallergenic and ideal for those with sensitive skin. Platinum jewelry is the perfect choice for a lifetime of everyday wear. Its density and weight make it a durable jewelry metal. Platinum does not wear away and holds precious stones firmly and securely. Like all precious metals, platinum scratches. However, the scratch on a platinum piece is merely a displacement of the metal and none of its volume is lost. In addition to its strength and density, platinum has another remarkable quality – pliability.
The ancient Egyptians were the first to use it in jewelry, however, widespread knowledge of the white metal stretches back only a few hundred years. Despite being worked with some skill by South American Indians over 1000 years ago, in 1590 Spanish Conquistadors while searching for silver discovered a white metal in the rivers of Equador. Since they did not have the ability to processes it they named it contemptuously platina (little silver) and discarded it. it was not until after the Spanish conquest of the New World during the fifteenth and sixteenth centuries that news reached Europe of a new white metal with unusual properties.
Platinum has a high melting point (3190 F or 1755 C) which limited its jewelry use until the invention of the oxyhydrogen torch in the mid 1800’s. In the late 1800s platinum-mania swept through Europe and Russia as Kings, Queens and Czars adorned themselves with anything and everything platinum. Early in the 1900s, the popularity of platinum reached U.S. soil and captivated the American public. At the outset of WWII, however, the US government declared platinum a strategic metal, and its use in non-military applications, including jewelry was restricted. To appease consumers, who preferred Platinum's white luster, white gold was substituted in Platinum's absence. When the ban was lifted after the war, platinum was unable to regain its place. Consumers, instead, turned to white gold, which mimicked platinum’s silvery luster but cost less.
It wasn’t until the early 1990s that platinum regained its niche and became immensely popular as a jewelry metal,
Let us take a quick tour thru the casting process.
The platinum casting process in some ways is similar to gold casting by utilizing the lost wax Jewelry casting method which has been in use for thousands of years. Since the discovery that metals could be melted. Sometime before 3000 B.C., artisans have been pouring molten metal into cavities shaped in stone, sand, and plaster. at some point in time wax was used as the medium which was encased in plaster or mud and once the wax was eliminated an empty shell or a mold with a negative imprint of the model was created in which the metal was poured into. Once solidified, the castings were then removed from the encasement into which they were poured.
Since melting platinum involves much higher temperatures then gold or silver different procedures, materials and equipment are required to produce quality platinum castings,
The platinum casting process involves the following steps:
1.Wax model and casting preparation.
Using the design, a wax model is carved , printed using a 3D printer , Milled using a CNC mill , or in a case of production of multiples the wax is injected using a rubber or metal mold , the wax models are then connected to one another on a sprue or a gate and then attached to a central wax rod to form a tree-like configuration. The alignment of the models and size and placement of the sprues is extremely important, and it is designed to allow platinum to flow through the “tree” with minimum turbulence or resistance and allowing the metal to solidify properly. The “tree” is then suspended inside a metal cylinder / flask which is filled with specialized plaster slurry mixed in a special mixer under vacuum, air bubbles and air pockets are removed from the slurry by exposing the flask during this process to high vacuum.
2. Model Burnout.
After hardening and curing, flasks containing invested models are placed in specialized ovens, where the wax is melted, and all carbon residue is evaporated at temperatures as high as 1600° F for 9-12 hours. A properly burned out flask will have no remaining residue of wax or resin, leaving behind a hollow cavity left by the wax models that were eliminated during the burnout process.
Various techniques are used to ensure a higher-quality casting. Centrifugal casting, vacuum-assisted casting, or pressure over vacuum casting. once the platinum reaches its optimal casting temperature the metal is automatically poured into the cavity in the flask filling all the open impressions created by the elimination of the wax models There are several common alloys typically used in platinum casting. The most common are Platinum 900 Iridium, which melts at 3,250 degrees Fahrenheit; Platinum 950 Iridium, which melts at 3,236 degrees Fahrenheit; Platinum 950 Ruthenium, which melts at 3,245 degrees Fahrenheit;
Once the flasks are filled it is necessary to remove the precious metal castings. The flask, now filled with glowing red platinum castings, is removed from the casting equipment. the flask is quenched in water . When the flasks are cooled, the investment is removed from the flask by water blasting, leaving behind a metal “tree” containing models as branches. The models are then clipped from the “tree” and inspected to verify that no defects are present and depending on the level of finish required will be either sent to the customer to be finished or forwarded to our jewelers who will clean the castings, assemble, polish and stone set to transform the casting into fine jewelry.
The need for the combination of knowledge and specialized equipment means that most jewelers rely on platinum casting companies to perform this service. The casting team at International Mfg. Co. have the experience and the tools required to deliver great platinum castings.
Our personalized service in placing your order and matching you with the services you require assures you that will get your project done right, the first time.
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