Making purple gold

Summary by Krater

The creator attempts to make purple gold, an intermetallic alloy of gold and aluminium, and cast it into a gold bar and a ring. After several failed attempts with casting defects, oxidation, and wrong colour hues, he successfully casts a bar and a ring of purple gold.

From the video

Answers: How do you make purple gold jewellery and cast it into bars and rings?

• purple gold alloy preparation
• gold and aluminium intermetallic casting
• aqua regia gold dissolving and recovery
• degassing molten metal with argon gas
• casting custom graphite molds with CNC router

What it concludes

• Purple gold is an intermetallic compound of gold and aluminium with the chemical formula AuAl2.
• Melting a standard mixture of 78.5% gold and 21.5% aluminium in air results in extreme brittleness, resembling glass or porcelain.
• Annealing the alloy at 600 degrees C helps recover a vibrant purple hue.
• Degassing molten aluminium with argon gas effectively removes moisture-induced micro-cavity porosity.
• Graphite molds milled with a CNC router provide a reliable method for casting purple gold without sticking.