Johnson's IA-423 is a "ternary eutectic" alloy, i.e., a composition comprising its three component elements (tin, silver and copper) that both melts and flows at a single low temperature, 423°F (217°C). Practically speaking, eutectic alloys are shinier, stronger and have a tighter, more refined grain structure than near-eutectic or non-eutectic compositions. As a result, IA-423 is becoming a highly desirable replacement for the lead-containing solders used in electronic assemblies, printed circuit boards and many other high-tech soldering applications. Audiophiles also claim that IA-423 is the best sounding solder they've ever heard, perhaps because of its high conductivity, owing to its high silver and copper content.
Solder wire is .032" in diameter with a Rosin flux core. This solder is 4.7%
Silver and 1.7% Copper and is second in sound quality only to the Mundorf solders. This solder can be difficult to work with but if used with the Cardas Flux Paste or Kester Flux Pen it flows as easily as Cardas or WBT.