The Delft Clay Method is a highly refined form of sand casting that substitutes genuine Delft Clay from Holland for ordinary casting sand.
The process was invented by Hans Karreman, a Dutch goldsmith.
Delft Clay is much finer than casting sand, providing remarkably sharp and highly detailed castings in gold, silver, copper-based alloys, pewter, etc.
Castings require very little finishing work.
Once you have cast your piece, the Delft Clay can be re-used.
Since this is a cold-molding process, molds can be made from patterns composed of wood, wax, epoxy, plastics, and, of course, metal.  
Because this is a type of sand casting, it is best suited to producing castings without pronounced undercuts.
A Delft Clay mold is created in these steps:

1. Fill and compact the Clay into one half of the aluminum ring frame
2. Remove excess clay with a straight edge (e.g. a flexible steel ruler)
3. Press your original pattern halfway into the clay.
4. Brush talcum powder over this surface of the mold
5. Install the other half of the aluminum ring frame, fill with clay and compact
6. Open the ring frame and remove the pattern
7. Carve out a pouring channel and vents
8. Pour in molten metal
The Delft Clay Casting Kit includes 4.4 lbs. of Delft Clay, a 60mm dia. Aluminum Ring Frame, and detailed instructions.
A 100mm diameter Aluminum Ring Frame is available separately.
View the Delft Clay video for complete step-by-step instructions on the Delft Clay Method.
Made in Holland.