The art of plating – coating an object with a thin layer of another (usually precious) material – has been around for thousands of years as a staple technique in the world of art and jewelry making. Gilding, or gold plating, is perhaps the most popular plating technique of all.
In modern times, there are many different ways to gild an object with a layer of gold. Electroplating and a number of chemical methods are all valued techniques for industrial gilding projects (e.g. making gold electrical contacts). More artistic projects, however, tend to favor the ancient techniques of mechanical gilding.
As the name implies, mechanical gilding relies on more elbow grease than its electro and chemical counterparts. As you may know, gold is an extremely malleable metal – which is the reason it’s so easy to plate things with. The first step to any gilding project is to pound the gold to be used as thin as possible (using modern techniques, this can be thinner than a sheet of paper) into gold foil. Afterward, they’re a few options for plating the gold onto a piece of art or jewelry.
In ancient times, artisans used the simple method of hammering the foil directly onto the piece. However, hammering alone was not sufficient to gild all types of material. So, gilding techniques evolved. Polished metal surfaces could be gilded if they were heated to just under their melting temperatures, and then pressed with gold foil. Other surfaces required a thin coating of gesso – a type of adhesive made of ground gypsum, chalk, and glue – to make the gilding permanent. For wood or paper surfaces (like illuminated manuscripts) grinding the gold into powder and mixing it with a binder made an easy to apply gilding substance.
The work of a skilled gilder can make an object appear to be made of solid gold. Manhattan Gold & Silver uses a number of assay types to determine gold content. Of these, a simple scratch test works best to determine if a piece is gilded or solid gold. If you discover your gold jewelry is gold plated, don’t fret! The most common gilded metal in jewelry making is silver, so your jewelry may still have some solid value.