Solder Properties

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.

RF Cafe - Tin Whiskers to the extreme (2nd picture down on page). Ah...the wonders of Pb-Free!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.

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.

Solder Alloy Melting Point (°C) Melting Point (°F)
5Sn-95Pb 307 585
0.5Sn-92.5Pb-2.5Ag 280 536
Sn/5Sb 243 469
100Sn3 232 450
99.3Sn-0.7Cu 227 440
96.5Sn-3.5Ag 221 430
Sn/3.0Ag/0.5Cu 219 426
Sn/3.8Ag/1.0Cu 217 423
Sn/3.5Ag/1.0Cu/3Bi 213 415
50In-50Pb 209 402
45Sn-55Pb 204 400
55Sn-45Pb 193 379
60Sn-40Pb 186 368
63Sn-37Pb 183 361
62Sn-36Pb-2Ag 179 354
97In-3Ag 143 289
Sn/57Bi 139 282
52In-48Sn 118 244

   1: Reduction of Hazardous Substances

   2: National Institute of Standards and Technology

   3: Pure tin