Gold-filled consists of a layer of karat gold bonded to a base metal using heat and pressure (the same process as Bi-metal). 14/20 GF is the designation for 14 karat gold-filled. The 14 refers to the karat of the layer of precious metal bonded to the base metal. The 1/20th indicates the ratio of karat gold to base metal by weight (5%). The base metal is CDA 220. A commercial brass alloy consisting of 90% copper and 10% zinc.
Gold-filled products are significantly advantageous in terms of cost, they allow you to provide the look and durability of solid karat products at a fraction of the cost. While care must be taken while working, soldering, and annealing, gold-filled items will have the same appearance and can last for years.
This should not be compared to gold-plated materials and products, which have a significantly thinner layer of gold and do not wear nearly as well.
Available in single and double clad; in both cases the gold content is 5% of the weight of the item. For a single clad sheet, the gold layer is only adhered to one side. The other (or bottom) is exposed base metal. For double clad sheets the gold layer is roughly equal to half that of single clad but it covers both sides. The total karat gold on double clad is 5% by weight, similar to that of a single clad. In both cases the edges are not gold clad.
Round, half-round and square are available in gauges as indicated in the tables, provided in dead-soft, half-hard and full-hard tempers. The gold content is 5% by weight. Particular care must be given to edges of half-round and square wires, as working these products may cause the exposure of base metal. In any case the ends are not gold clad, they are exposed base metal. This should be addressed in the metal products, as these areas may tarnish or react with exposed skin.
Main manufacturers of gold-filled semi-finished products
Leach and Garner
Hauser and Miller ( www.hauserandmiller.com)
Products on Amazon
14K gold-filled wire 24 Gauge half hard
14K gold-filled wire 22 gauge dead-soft