Object Type
This is a demonstration sample of a Sheffield plate ingot at the stage just prior to being heated in the furnace to fuse the silver sheets with the copper ingot. Silver sheets were embedded into the copper ingot by a hydraulic press. Then copper, or sometimes iron or brass plate, covered in a chalk paste (to prevent it fusing to the silver sheet) was placed on top to protect the silver surface from fire damage in the furnace. The pieces of metal were then tied together by iron wire at regular intervals along the ingot, and the exposed edges, where the silver and copper came into contact, were swabbed with a borax solution. The block was now ready for firing.

Materials & Making
The process developed by Joseph Hancock (1711-1790) for large-scale production of fused (Sheffield) plate has differed little throughout the course of the industry. An ingot of copper was covered with a thin sheet of sterling silver. These ingots were approximately 1½ to 1¾ inches thick and 2½ inches wide by 8 inches long (4 by 6 by 20 centimetres). This could vary according to the weight and size of the plated sheet that was required to be made. Generally speaking, however, the thickness of the silver sheet was 1/40 that of the copper block, which meant that 10 to 12 ounces of silver were used for every 8 lbs of copper.

People
After about 1760, it became the practice to plate two sides of the copper ingot so that the resulting sheet was plated with silver on both sides. In 1830 Samuel Roberts (1763-1849) patented a variation (no. 5963), whereby a sheet of German silver (an alloy of copper, zinc and nickel) was inserted between the silver and the copper block. This produced a laminate of far greater durability.