The “Paste for Gold Filled” has a gold content of approximately one karat, or about the karat value of 1/20th 12 karat gold filled material, also known as 12/20. The extra easy flow point of 1250F (677C) helps prevent damage to the bonded gold layer caused by overheating. The addition of Firescoff® Rh to the soldering operation adds greater protection to this layer by preventing firescale.
Solders for “Gold Filled” are available in sheet, wire, and paste. However, paste solder offers particular advantages when used when soldering rope chain, hollow shells, findings, earring posts, and jump rings. The “Paste for Gold Filled” contains a highly active combination of chemical fluxes added to the paste to clean and protect the base metal and solder during the heating cycle.
As with all low karat alloys, the solder will tarnish over time, and gold plating is required after soldering to insure uniformity of color and resist tarnishing. In order to avoid the need to electroplate, use a soft 12K or 14K solder. This will prevent tarnishing of the solder joint and provide a better color match.