Kester 04-7068-0000 is Lead-Free, Ultrapure SAC305, Low Dross Bar Solder that is sold in a 25 lb box. It is comprised of SN96.5AG3.0CU0.5 or 96.5 percent tin, 3 percent silver, and .5 percent copper.
Ultrapure SAC305 Product Description: Lead-free wave soldering processes tend to produce a greater amount of dross than traditional leaded processes. For this reason, Kester produces all lead-free bar solder products with anti-drossing technology to improve process control and to allow the user to get the most value for the money with minimal maintenance costs. Kester Ultrapure SAC305 Bar solder was designed to minimize the amount of dross generated in wave soldering, selective soldering or dip soldering process.
When molten solder comes in contact with air, it forms metal oxides or dross. The dross mixes in with the solder in the upper layer of solder in the solder pot form a pasty solder dross mixture. Many solder impurities have been known to contribute to dross formulation - aluminum, cadium, iron and zinc are the most common of these. The purity level of Kester Ultrapure SAC305 meets the industry requirements for allowable impurity levels, which helps control dross levels. Aside from exceptional control on solder purity, the Kester Ultrapure SAC305 manufacturing process integrates a low dross additive to minimize dross formulation during the soldering process. Additionally, Kester employs an extrusion manufacturing technique to minimize oxidation and alloy segregation during the manufacturing process. Old-fashioned methods of casting individual bars lacks protection from the atmosphere in the molten state and exposes more surface area which produces correspondingly more oxide.
Kester Ultrapure SAC305 yields less dross, bright solder joints, and a reduction in defects in wave, selective and dip soldering processes. It meets the requirements of current industry standards for allowable impurity requirements. Kester SAC305 bar solder purchased directly or through stocking distributors will conform to these requirements. Some military contracts reference process specifications, such as WS-6536E, which require 0.2 - 0.5% antimony in the solder. MIL-STD-2000A, on the other hand, does not specify a minimum percentage of antimony. There is no requirement that antimony must be included in solder. Kester does not recommend the inclusion of antimony unless specifically required by specifications. Kester SAC305 conforms to the requirements of J-STD-006 (formerly QQ-S-571F).
Ultrapure has a melting point of 217 degrees C / 423 degrees F. Applications SMT / Hand / and Wave Soldering.