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.The Delft Clay Casting Kit includes 4.4 lbs. of Delft Clay, a 60 mm dia. Aluminum Ring Frame, and detailed instructions. A 100 mm diameter Aluminum Ring Frame is available separately.Made in Holland.