Abstract: Heavy metal solders having exceptional ability to wet non-metals, especially glass, are produced by the incorporation of small amounts of the light reactive metals lithium, sodium, potassium, rubidium, cesium, calcium, or magnesium into the heavy metal solder compositions. These heavy metal solder compositions consist essentially of alloys contained within the heavy metal system Pb-Sn-In-Bi-Cd-Sb-Hg-Ga-Ag-Au or within subsystems thereof wherein each heavy metal element present in the system or subsystem can potentially constitute nearly the whole of the total depending upon the specific composition chosen. In cases where a low melting point is desired the resultant solder will in general have the formula:A.sub.a B.sub.bwherein A is at least three metals selected from the group consisting ofPb, Sn, In, Bi, Cd, Sb, Hg, Ga, Ag, and Au;and B is at least one metal selected from the group consisting ofLi, Na, K, Rb, Cs, and Ca, and Mg; andwhereinb ranges from about 0.0001 to about 0.1; anda ranges from about 0.