The History

In 1889, the decorative technique of applying silver designs to glass was patented by Oscar Pierre Erand and John Benjamin Round for Stevens & Williams Ltd in Birmingham, England. It had the shortcoming that the reverse side of the silver next to the glass would tarnish and turn dark. In 1893, a patent was registered in the US by John H. Sharling of New Jersey, which had the distinct advantage that the reverse side was white and stayed that way by utilizing electroplating. He shared his methods with everyone and silver overlay came to its first peak in the early 1900's. There were two distinct eras of Silver Overlay. From 1895 to the early 1920's, this art had its own avid following and became a decorative rage. But during this first era, it was very labor intensive and expensive and this period was over by the mid-1930's.

Glass Collector's Digest records that the cost to produce a decanter made in the early 1900's was .90 cents for the glass blank, $4 worth of silver, and $5 for the added labor for the silver overlay design. A revival of silver overlay followed immediately after WWII that lasted until the late 1950's.

The Method

A designer would decide what pattern was most suitable for a piece of glass, such as grapevines on a wine carafe. The design would be hand painted onto the surface with a special flux – a mixture of turpentine and powdered silver, copper or brass. The glass was fired in a kiln to permanently fix the pattern onto it, then cooled and cleaned and placed into a water filled tank with a sheet of silver. Electric current was then set up between the silver and the tank walls. The silver ions would migrate from the sheet and attach themselves to any other silvery metal surface within the field of the electric current. The longer the process continued, the thicker the build-up of the silver coating. After about 10 hours, the glass would be removed from the bath and buffed to create a glisten. If the layer was thick enough, silversmith tools could then be used to enrich the detailing. Sometimes the manufacturers name or word "Sterling" were gently stamped into the silver.

During the 2nd revival of silver overlay in the late 1940's, in a more economical process, the design was printed on sheets of paper with an inky flux or lightly etched into the glass. The sheets or etch applied the pattern to the glass for electroplating. Or an alternative method involved coating the whole surface with silver, painting the design onto the silver with a "Resist" and then dissolving away the unwanted parts of the silver. In later years, the invention of coating the silver deposit at time of manufacture with Rhodium prevented tarnishing. And if you look at the back of a piece of crystal and it looks yellow, you can tell the under-metal was brass.

Silver decorating companies did not make the glass and then decorate it. It was impossible for them without having a furnace to produce the molten glass. Some companies even owned molds, but contracted other companies to make the pieces for them. Blanks from different companies could be decorated with the same silver overlay and merchandized as sets.

Conversely, glass companies like Cambridge, Heisey, Steuben and others had no silver plating facilities or chemical ability to apply the silver to glass, so did not do their own decorating.