<P> Various fusible alloys can be used as solders with very low melting points; examples include Field's metal, Lipowitz's alloy, Wood's metal, and Rose's metal . </P> <P> The thermal conductivity of common solders ranges from 32 to 94 W / (m K), and the density from 9.25 to 15.00 g / cm . </P> <Table> <Tr> <Th> Material </Th> <Th> Thermal conductivity (W / m K) </Th> <Th> Melting point (° C) </Th> </Tr> <Tr> <Td> Sn - 37Pb (eutectic) </Td> <Td> 50.9 </Td> <Td> 183 </Td> </Tr> <Tr> <Td> Sn - 2.8 Ag - 20.0 In </Td> <Td> 53.5 </Td> <Td> 175--186 </Td> </Tr> <Tr> <Td> Sn - 2.5 Ag - 0.8 Cu - 0.5 Sb </Td> <Td> 57.26 </Td> <Td> 215--217 </Td> </Tr> <Tr> <Td> Pb - 5Sn </Td> <Td> 63 </Td> <Td> 310 </Td> </Tr> <Tr> <Td> Lead (Pb) </Td> <Td> 35.0 </Td> <Td> 327.3 </Td> </Tr> <Tr> <Td> Tin (Sn) </Td> <Td> 73.0 </Td> <Td> 231.9 </Td> </Tr> <Tr> <Td> Aluminum (Al) </Td> <Td> 240 </Td> <Td> 660.1 </Td> </Tr> <Tr> <Td> Copper (Cu) </Td> <Td> 393--401 </Td> <Td> 1083 </Td> </Tr> <Tr> <Td> FR - 4 </Td> <Td> 1.7 </Td> <Td> </Td> </Tr> </Table> <Tr> <Th> Material </Th> <Th> Thermal conductivity (W / m K) </Th> <Th> Melting point (° C) </Th> </Tr>

What are the two most commonly used metals in solder