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New
Black Hills Gold jewelry designs begin with detailed drawings.
After a design is selected, an actual size model of the item
is created in wax. Sometimes silver and production models
are created using the "lost wax" method of casting,
which will be detailed later.
Pure 24 Karat gold bars, and stocks of pure silver and copper
are the basic materials. These precious metals are not required
to be mined in the Black Hills, as some rumors contend. Pure
gold and other precious metal stock can be acquired from anywhere
in the world. The finished jewelry known as Black Hills Gold
must be produced here in the Black Hills of South Dakota.
(see our History page.)
The pure 24 Karat yellow gold is alloyed with exact percentages
of other metals to achieve a more durable karat quality of
10K, 12K or 14K, and used for ring shanks and the base of
other items. The different colors of gold used for leaves
and other details are made when the pure 24 Karat yellow gold
is alloyed with copper to achieve the traditional 12 karat
pink (or red) gold, and the gold is combined silver to create
the 12 karat green. The resulting gold bars are then readied
for rolling.
The alloyed gold bars are rolled by
presses to different thicknesses for different types of jewelry.
Component parts, or findings, are carefully
stamped, one at a time, out of the rolled gold sheets using
patterns and dies. The solid gold leaves and other patterns
are then ready to be added to a cast jewelry base, created
using a method called "lost wax casting."
Lost
wax casting begins with an original metal model, often silver,
of a jewelry item. A vulcanized rubber mold is made from the
metal model and is reusable for making a design over and over.
A wax model is then made when hot molten wax is injected into
the mold.
The wax model is removed from the mold and mounted to a wax
stem called a sprue, which creates an airway for casting.
Many designs mounted to this sprue create a "tree."
The tree is place inside a stainless steel cylinder, and liquid
investment compound (casting plaster) is poured around the
wax patterns in the can. After the plaster hardens inside,
the cylinder is placed in an oven and baked for several hours,
melting the wax away. The cavity inside the hardened plaster
provides an exact duplicate to be cast and is filled with
molten gold. The cylinder is quenched in cold water, shattering
the plaster and exposing the gold jewelry. The extra portions
of the cast pieces where they were attached to the tree are
ground away.
The cast pieces are then polished by one of two methods, either
traditional hand polishing using a wheel, or a process called
"tumbling." Many castings at one time are placed
in a tub or cylinder with different sizes and shapes of metal,
rubber or other materials in a liquid solution, then agitated
or rotated until they have been polished smooth. These smooth,
cast pieces are then ready for the stamped components, like
leaves and grapes, to be mounted on them.
Some manufacturers use the traditional method, where the stamped
components are individually hand-soldered to the cast gold
frame using torches and karat-gold solder. Other factories
place the solder and components together on the cast item,
leaving several such assemblies in a soldering oven where
they are soldered by the heat of the oven.
Some manufacturers again polish or tumble the assembled items,
while others do not and polish using different methods. The
jewelry is cleaned in a mild acid bath, then inspected using
high quality standards. Then, each piece is electro-plated
with 24 Karat yellow gold. A finishing technique known as
"wriggling" removes the plating from the pink and
green leaves, creating a textured or frosty effect. Each leaf
vein is then hand-engraved for a brilliant, light-catching
finish.
Each piece is polished in several different steps to bring
out its brilliant luster. If the item has gemstones in its
design, it is sent to the stone setting department for mounting.
Finally, a careful inspection completes the process that began
with pure 24 Karat gold and finished with a truly unique and
beautiful, handcrafted jewelry item -- Black Hills Gold jewelry.
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