What is "Woods Metal" I have a piece of what I have been told is "Woods Metal" it melts at 168F.  I am "curious" about how they make it, how low can the melting temperature be?
Here is some additional info from web

Wood's metal, also known as Lipowitz's alloy or by the commercial names Cerrobend, Bendalloy, Pewtalloy and MCP 158, is a eutectic, fusible alloy with a melting point of approximately 70 °C (158 °F). It is a eutectic alloy of 50% bismuth, 26.7% lead, 13.3% tin, and 10% cadmium by weight.

I have experience using the material for fixturing of difficult to secure /  shaped parts for machining. It can also help in fixturing/holding - then later melted away. 

The eutectic composition will privide lowest Tm and get the info from a phase diagram. 

Do not add mercury for safety reasons.