In Antiques the term " Sheffield Plate " is used to describe silverplated
pieces made by the method of fusing silver to copper as invented by Thomas
Boulsover (Bolsover) in 1742.
Thomas Boulsover a cutler from Sheffield, England, discovered that a
combination of fused silver and alloyed copper retained all the ductility
of both metals and behaved similar to glass in the making of " Millefiori ".
Sheffield Plate thereto is made, by covering a piece of copper alloyed
with lead and zinc, with a piece of silver and heating it in an oven until
the silver fuses to the copper.
After cooling, the combined metals may be rolled into larger, thinner
sheets of silverplated copper.
Boulsover started making siverplated buttons, but Joseph Hancock ,
after his apprenticeship by Boulsover produced all sorts of pieces.
Matthew Boulton began, in 1762, to produce fused Sheffield Plate at
Soho, Birmingham, England and became the best known master in this field.
Later this method was widely adapted and pieces where made in many
places in England, Ireland and North America.
Electro plating in the 1840's overtook fused Sheffield Plate, as this
method allowed for cheaper more elaborate pieces to be manufactured.
1773 injunction obtained by London silversmiths against the marking of
1774 Sheffield makers regained the right to mark their wares with
makers names and markings differing from those used for marking silver.
Genuine Sheffield Plate is been a collectors item since the late 19th
century as the special glow of silver combined with the glow of copper
through some worn places has a romantic color which even Sterling silver
Sheffield Plate is recognized by the collector by it rolled over edges
and solid silver soldering which shows up at worn spots as well as by the
striations on spun parts.
Resoldering with silver and light resilvering of excessively worn
and loose parts is generally excepted as normal by collectors.