With the adverse effects of leaded soldering known, some key individuals and countries decided it was best to not use leaded solder anymore. In 2006, the European Union adopted the Restriction of Hazardous Substances Directive (RoHS). This directive, stated simply, restricts the use of leaded solder (amongst other materials) in electronics and electrical equipment. With that, the use of lead-free solder became the norm in electronics manufacturing.
Lead-free solder is very similar to its leaded counterpart, except, as the name states, it contains no lead. Instead it is made up of mostly tin and other trace metals, such as silver and copper. This solder is usually marked with the RoHS symbol to let potential buyers know it conforms to the standard. Once again, our friends at Sparkfun show us How To Solder. At Farnsworth Electronics, we carry the most popular 1/2 lb. spools from Qualitek. We carry the most popular 1 lb. spools from Kester Solder. We also carry 1/2 oz. pocket packs in both 60/40 and 0.35 oz. SN62/PB36/AG02 Silver pocket pack. The 2% silver is required when soldering to silver or silver plated components/leads. The small percent of silver in the solder prevents the silver on the leads from migrating into the solder resulting in a weak or brittle solder connection. Click on the links below to go to the manufacturers website for more information.