Variable melting point solders and brazes having compositions comprising a metal or metal alloy powder having a low melting point with a metal powder having a higher melting point. Upon heating, <i>in-situ</i> alloying occurs between the low and high melting point powders such that solidification occurs at the solder or braze temperature thus creating a new, higher solidus (or melting) temperature with little or no intermetallic formation. A solder comprising Sn powder mixed with a Sn-Bi eutectic powder having a composition of 63wt.% Sn: 57wt.% Bi such that the bulk composition of the mixture is 3 wt.% Bi has an initial melting point of 140 DEG C and a re-melt temperature of 220 DEG C after heating due to in-situ alloying. A composition of Pb powder mixed with a Pb-Sn eutectic powder having a composition of 62wt.% Sn:58wt.% Pb such that the bulk composition of the mixture is 15 wt.% Sn has an initial melting point of 183 DEG C and a re-melt temperature of 250 DEG C.
