The Process

The Lost Wax Casting Process dates back to early Egypt and later in China during the Chang Dynasty, 1776-1122 BC. The Lost Wax Casting Process was used mainly to reproduce metal parts and to reduce the time and labor needed for producing parts in quantity by metal smiths. Molten metal was poured into molds and removed when solidified. Since then modern technology has made the metal smith basically extinct.

The Lost Wax Casting Process has basically five steps to produce a raw casting. A craft process, all the steps in the Lost Wax Casting Process are equally important. Today's technology enables us to mold, wax, and cast a smoother, more intricate and complex part, with more precision than ever before

Model:

A model is a metal pattern of the design to be reproduced. It is made 5% larger than the finished casting product. A hard metal is used to withstand the temperatures required for vulcanizing molds. There are many ways to create a model. The customer can realize a significant cost saving and insure a quality casting by consulting with an experienced caster who is aware of current advancements and methods of production. Common modifications may involve undercuts, shrinkage, thickness/thinness, and temperature uniformity.

Molding:

Most molds consist of two parts which create a negative cavity of the design which will be cast. Wax or plastic is injected into the mold to make a positive copy. Molds are made of various types of rubbers, metals, plastics or plasters. Vulcanized rubber is the most common and is the least expensive. It requires the model to be 5% larger. The mold must be able to withstand a temperature of 350 degrees Fahrenheit. Minimum size rubber mold is 3" long x 2" wide x 1/2" thickness. Maximum size rubber mold is 10" long x 6" wide x 6" thickness.

Waxes:

The Wax pattern is a positive copy of the design to be transferred into metal. The waxes or plastics are produced by injecting material directly into the cavity of the mold. It is recommended however, that samples be made to insure a proper burnout for a clean surface before the beginning production. A minimum thickness of .040 is required for proper fluidity. The maximum wax is 10" long, 5" wide, and 5" thick.

Investment Mold:

The Investment mold is a negative copy of the wax pattern. Investment powder, a form of plaster. is mixed with water, and poured as a liquid directly over the wax pattern to make an exact negative mold of the wax design. There are many types of investments. The right investment depends on the way waxes will be treed and grouped inside the flask and the metal which will be used. Once the investment becomes solid over the waxes, the mold is put into ovens to remove all of the wax and cure the investment.

Casting:

Castings are exact metal copies of the mold or wax chosen to be reproduced. The two most common casting techniques are centrifugal casting and vacuum assist casting. Both processes have special requirements for a quality casting, gating and venting being the most common. As a general rule filigree and thinner pieces are more successfully cast centrifugally and heavier, thicker pieces are produced in a vacuum assist process. Our minimum thickness is .040 and our maximum weight per piece is 10 lbs.

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