Values presented in the table below are for some of the most commonly used solders. With the push for lead-free (Pb-free) versions that conform the the RoHS¹ initiative that will be in effect in Europe in the summer of 2006, new alloys have been developed that use little or no lead at all. For those application, this resource compiled by NIST² and the Colorado School of Mines will be very helpful.

A big problem with lead-free (aka Pb-Free) solder is that the higher the tin content, the more likely the growth of "tin whiskers." This phenomenon where tiny tendrils grow out of the solder is still not fully understood. The problem is that short circuits can be established between adjacent conductors, and within a high density connector or a fine-pitch IC package. Some military and space-based platforms ban the use of Pb-Free solders for that reason.

• How to Solder Various Metals: A handy set of tutorials from the Kester solder people.
• Database for Solder Properties with Emphasis on New Lead-Free Solders

See my handy tip for holding solder while manually soldering.

In the chart below, any solder compound that does not have a "Pb" component is lead-free.


   1: Reduction of Hazardous Substances
   2: National Institute of Standards and Technology
   3: Pure tin