Normal solder (Sn63 Pb37): with flux, wetting o

Pure Indium - In 99.995: no flux, wetting x, low melting temp, like paste

Pb93.5 Sn5 Ag1.5: with flux, wetting o, high melting temp (soldering iron setting 380~430F)

Cryo solder In97 Ag3: no flux, wetting x, low melting temp, like paste