NNP

Cast Double.  A medallic item with designs on both sides, as the obverse and reverse are cast separate then joined together; not single-sided. Cast double is, particularly, a numismatic term in that no other objects of equal size, shape and two-sidedness are joined together like medallic items. The two halves, called plates, can be solid, but are usually cast hollow and are soldered together. (The lead solder not only is the adherent holding the two plates together but also the drop-in giving the piece added strength). Medallic items are cast double as any casting – it is more suitable than diestriking (no diestriking equipment available, a size larger than can be diestruck with fewer needed than die making requires).

There are two kinds of double-sided medals:

∙ Cast – When both halves of a medallic item are cast

each side is called  a plate; the item can remain hollow,

or a metal drop-in can be added to make it somewhat solid.

∙ Electroformed – When both halves of a medallic item

are made by electroforming they are called shells;

they also can remain hollow, or the drop-in metal

added to strengthen it. When made of two electroformed

shells this is technically a galvano medal.

Where two halves, made by any method, are brought together there is usually a seam visible around the edge. This is usually trimmed or chased to smooth it, and often buffed to make it as inconspicuous as possible. The fabricated item is then given a patina finish as one uniform medallic item.

A two-sided cast piece not joined, but of one uniform mass cast in a two-sided mold is termed double-sided and it is always cast solid.    

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