A Brief History of Gilding Techniques

Mechanical gilding, chemical gilding, and electroplating

Gilded Ages

• Gilding is an ancient art used to plate gold to other materials for artistic purposes.

• Gilding has been around for thousands of years as a classic technique in the worlds of art and jewelry-making.

• There are many ways to gild an object, all of which have evolved over generations.

Mechanical Gilding

• Mechanical gilding is the oldest and most labor-intensive method for covering an object in gold.

• The first step to any mechanical gilding project is to pound the gold as thin as possible into gold foil.• This is possible because gold is the most

malleable of all metals.

• After pounding, there are a few options for plating the gold onto a piece of art or jewelry.

Mechanical Gilding

• To complete the mechanical gilding process, the gold foil can be:• Hammered directly onto the piece• Pressed onto an object that has been heated to just under its

melting point• Pressed onto an object that has been coated with gesso (a

type of adhesive made of ground gypsum, chalk, and glue)

• For wood or paper surfaces (like illuminated manuscripts), grinding the gold into powder and mixing it with a binder made it easy to apply without hammering or heating.

Depletion Gilding

• Depletion gilding is another technique that evolved from mechanical gilding. • Depletion Gilding is a form of chemical gilding.

• Rather than depositing a layer of pure gold onto an object, depletion gilding removes non-gold elements from a surface, leaving behind a layer of pure gold.

Depletion Gilding

• Gold is extremely resistant to oxidation, but the impurities it is naturally alloyed with are not.

• By submerging a gold alloy in nitric acid, the surface impurities will be depleted leaving a layer of pure gold. • With the impurities gone, the gold is

pocked with millions of microscopic cavities, which gives it a dull or matte appearance. Its luster can be restored by burnishing or polishing.

The Pinnacle of Gilding

Gilding techniques continued to evolve into multiple varieties. The most advanced of these that we’ll cover is the Wohlwill Process.

• The Wohlwill Process was invented by Hans Emil Wohlwill, a German engineer, in 1874.

• When done correctly, the Wohlwill Process can produce gold samples of 99.999%.

The Wohlwill Process

The Wohlwill Process uses three main components:

• The anode – an electrode through which electric current flows into a polarized electrical device (made with impure gold)• The cathode – an electrode through which electric

current flows out of a polarized electrical device (made out of pure 24k gold)• The electrolyte – an electrically conductive substance

(made of chloroauric acid, which is created by dissolving gold in aqua regia)

The Wohlwill Process

• With all components properly set up, an electric current is applied.

• Electricity travels from the anode, through the conductive electrolyte, and into the cathode.

• When this occurs, the gold in the impure anode dissolves and its ions travel though the electrolyte acid, then electroplate or “stick” to the 24k gold cathode. This continues until the anode is completely dissolved, resulting in a cathode plated in extremely pure gold.

About MGS

Manhattan Gold & Silver (MGS) is a precious metals refiner that has been based in Manhattan’s historic Diamond District since 1985. We are a B2B company that buys and recycles precious metal scraps that accumulate in other businesses. We serve:

• Jewelers• Pawnbrokers• Dentists• The industrial sector• Antique dealers• Machinists • Domestic mining• And more!

• MGS also creates charts, calculators, and other online tools for our customers to use.• Try our Precious Metals Prices app, which lets you monitor the real-time precious metals

market situation from anywhere, right from your iPhone, iPad, or Android device.

Recycle your Precious Metals for Profit• MGS accepts gold, silver, platinum, and palladium.

• Payouts are based on the London Fixing.

• Up to 99% payout (among the highest in the US)• Up to 98.5% for gold brought in for hand testing.

• Not in NYC? Ship us your precious metals using our Ship & Sell service which offers:• Same day wired payment (once lot is received)• Discounted, insured shipping• Payout calculator

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