Core
Core. In clad and bonded metallurgy, the center metal to which outside metals are attached. In a sandwich construction the core is usually the lower cost alloy with the outer lamina layers the higher value alloy so the individual piece will have the characteristics of the outer metal while the total cost would be less than one of the solid outer composition. In metalcasting the core is the mandrel around which a hollow casting is made.
excerpted with permission from
An Encyclopedia of Coin and Medal Technology
For Artists, Makers, Collectors and Curators
COMPILED AND WRITTEN BY D. WAYNE JOHNSON
Roger W. Burdette, Editor