The Delft Clay Method is a highly refined form of sand casting that replaces ordinary casting sand with genuine Delft Clay from Holland. This process was invented by Hans Karreman, a Dutch goldsmith. Delft Clay, much finer than casting sand, enables the production of remarkably sharp and highly detailed castings in gold, silver, copper-based alloys, pewter, and more. These castings require very little finishing work. Moreover, once the casting is complete, the Delft Clay can be reused. Since this is a cold-molding process, molds can be made from patterns composed of wood, wax, epoxy, plastics, and, of course, metal. However, because it is a type of sand casting, it is best suited for producing castings without pronounced undercuts.

The creation of a Delft Clay mold involves the following steps:

• Fill and compact the Clay into one half of the aluminum ring frame.
• Remove excess clay with a straight edge (e.g., a flexible steel ruler).
• Press your original pattern halfway into the clay.
• Brush talcum powder over the surface of the mold.
• Install the other half of the aluminum ring frame, fill with clay, and compact.
• Open the ring frame and remove the pattern.
• Carve out a pouring channel and vents.
• Pour in molten metal.