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Electroplating: gold, silver and rhodium baths

· 1 min read · Techniques

Illustration: Electroplating: gold, silver and rhodium baths

In electroplating, the piece is immersed in a bath containing ions of another metal and current is passed through: the metal is deposited in an even layer, from tenths of a micron to several microns.

Steps of the technique: Degrease, Activate, Connect, Deposit, Rinse, Dry and polish
Summary of the steps

Steps #

  1. Deep cleaning: degreasing and, often, electro-cleaning.
  2. Activation, so the metal accepts the plating.
  3. Electrolytic bath (gold, silver, rhodium, nickel…) with the right current and time.
  4. Rinsing, drying and final polishing.

Common baths #

  • Rhodium: bright white over white gold and silver.
  • Gold: in several shades.
  • Silver: on costume jewelry and cutlery.
  • Black (rhodium or ruthenium): dark finishes.

Thicknesses #

A very thin layer wears off soon; a thicker one lasts longer. Hence the different levels of plating.

Safety #

The baths contain toxic products (cyanides in some gold baths): this is work for specialized workshops.

Step by step #

  1. Degrease. Clean the piece with detergent or ultrasonics.
  2. Activate. Dip in a mild acid.
  3. Connect. Hang the piece as the cathode.
  4. Deposit. Apply current for the stated time.
  5. Rinse. Rinse with deionized water.
  6. Dry and polish. Dry and brighten with a cloth.

Tools and materials #

  • Tank, rectifier and anodes
  • Gold, silver or rhodium baths (rhodium)
  • Thermometer and agitator
  • Protective equipment

Common mistakes #

  • Greasy piece: the bath does not take.
  • Excessive time or current: burnt deposit.
  • Contaminating the bath with other metals.
  • Not disposing of residues safely.

See also #

This entry was drafted with the help of AI and is pending review by the author.