Galvanic finishes

Ever wondered how your beautiful gold plated jewellery was produced? Galvanic finishes, in simple terms, refers to the process of applying a coating of another metal to the surface of the base metal used to manufacture the object so as to delay corrosion.

The object is first drawn by hand or through CAD and then designed by hand, prototyping or 3D printing to produce the Master. A mould created from the Master will then be used to replicate the object into the desired number of pieces known as MANDRELS. These are then created either by melting and centrifuging a metallic tin/bismuth alloy in the mould or by injecting a resin or wax into the mould.

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Imperfections on the surface of the Mandrels, such as parting lines from the mould, will be eliminated by mechanical polishing. Copper layer deposition, the first of the Galvanic finishes is then applied to get the surface of the objects as smooth as possible.

The required number of mandrels are fixed and positioned in a manual or automatic electroforming machine where further galvanic finishes are applied. The mandrels are coated with a thick layer of gold (at different carats), silver or bronze, through the process of electrolysis and other deposition steps. The thickness of the coating can range from 100 to 450 micron, depending on the desired weight and mechanical resistance for the final object.

Continuing with the Galvanic finishes, an application of electrolytic copper prevents gold from coming into contact with the metal alloy and producing amalgam. At least a second hole is drilled onto the mandrels to create an escape way. Any mandrel material (metal alloy or resin) that’s inside the electroformed shell is cleared out (Emptying,), and metal alloy residuals are eliminated by chemically dissolving them, under aspiration hood, in a strongly acidic solution which does not attack the shells.

Finally, the object goes through Annealing, a specific thermal treatment, of the cleaned shells to allow the different carat gold layers to diffuse into each another.

For more information about the galvanic finishes and electroforming processes, don’t hesitate to contact us.