Sapphire Jewelry
A Guide To Jewelry Manufacture
Precious metals are made into jewelry by employing four common methods:
The techniques of die striking, wax casting, electroforming, and hand fabrication are not mutually exclusive; finished jewelry is often a combination of pieces created by different manufacturing methods.
Die Striking
Die striking or stamping is a very old method for making coins and jewelry. Today, the jewelry making process begins with the creation of a pattern or design in the form of a metal die . The die is usually comprised of two parts, a punch and a mold, which are often made of steel. The dies are placed into powerful machines that are fed “blanks” (plain pieces) of precious metal. When the blanks are struck by the die, a three dimensional piece of jewelry is created.
Die striking is a popular manufacturing method; once the die is created, it is a rapid and cost effective means for producing a high quantity of items. The die striking process also creates items with consistent quality. Die struck items have sharp edges and crisp detail and require minimal cleaning before polishing.
The main benefit of the die striking process is that it yields products that are dense and durable. This means die struck jewelry wears well and can withstand a high polish. Die struck items are also ideal for engraving. Because it produces items that are naturally strong, the die striking process is especially recommended for the manufacture of prong settings, although it is also commonly used to make pendants, earrings, and rings.
Wax Casting
Modern wax casting methods are derived from an ancient “lost wax” technique used by the Egyptians over 3,500 years ago. When this technique is used for mass production today, wax is repeatedly injected into a rubber mold in order to create thousands of identical pieces. The identical wax items are attached to a wax “tree” which is then covered with a plaster-like material called the “investment.”
Once the investment has dried, it is heated to melt the wax within. The melted wax is drained from the mold to leave behind a hollow space that is then filled with molten metal. A vacuum or centrifugal force pulls the molten metal into every nook and cranny within the mold. The metal is allowed to solidify and harden. When the investment is removed, it reveals a precious metal “tree” of castings. The castings are removed from the trees, cleaned, and polished.
The casting technique is a relatively rapid and economical means of making identical pieces. Because the originals are made from wax, which is easily manipulated, the technique offers unlimited design potential. However, cast pieces are slightly less dense than die struck pieces and may wear easier. Cast pieces typically require more polishing and clean up than those produced via other manufacturing techniques.
Electroforming
Electroforming is a jewelry making technique that uses electricity to deposit metal over a model. It is related to the technique of electroplating, which also became popular in the first half of the 19th century. When an item is electroplated, a model (usually made of wax), is dipped in electrically conductive paint and allowed to dry. Many identical models are attached to a frame and submerged in a special chemical bath.
An electrical current is passed through the bath to give the models a positive charge. The positively charged models will then attract negatively charged particles of a metal such as gold. The models are rotated within the bath to give an even coating of precious metal, which is built up in successive layers. When the metal layer is sufficiently thick, the wax model is melted away, leaving a hollow shell of precious metal.
Electroformed pieces can be exquisitely detailed. While they naturally have a matte finish, they can also be polished to have a bright finish. Originally, gold electroforming required 23K or 24K gold, but since the 1980s electroformed pieces have been manufactured from 14K and 18K gold. This has helped to increase the popularity of this process.
Because electroformed pieces are hollow, they can be large but relatively lightweight, making them economical and well suited for earrings and other jewelry items where weight is a concern.
Unfortunately, electroformed pieces dent very easily. Because of this quality, the process is not typically used to make rings or bracelets. It is also difficult to repair electroformed jewelry; it is more common for manufacturers to replace a piece than repair it.
Hand Fabrication
Hand fabricated jewelry has been made for thousands of years. The process requires a great deal of time, skill, and patience. In an age dominated by mass production, it is less common to find one-of-a-kind hand fabricated pieces today. The term hand fabricated applies to a piece of jewelry that has been created entirely with hand tools and methods including hammering, sawing, carving, soldering, setting, and finishing.
Because there is some ambiguity in the term handmade, jewelers generally prefer to use the more precise term “hand fabricated.”
Hand fabricated jewelry is prized for its quality and originality. Because hand fabricated pieces are painstakingly produced by skilled craftsmen, they are often beautifully finished on all sides, including the back and other hard to reach areas.
Now that you have explored the manufacturing processes, we will delve into the types of Finishes and Decorative Techniques | Definitions and Pictures that make jewelry so personal and special.
