L 1308 (OTTO) Lead rod, 99.999% Cas 7439-92-1 - used as a coolant in nuclear reactors. L 1308 (OTTO) Lead rod, 99.999% Cas 7439-92-1 - used to be mixed with tin to make the pipes in pipe organs. Different amounts of lead make different sounds. In addition, lead has found its usage in solder.