On Tue, 27 Oct 2009 16:55:17 -0700, "T.Alan Kraus"
wrote:

Scenario facts: a piece of stranded copper battery cable about 3.5"
long with two soldered connectors at each end, used for ground
connection on a motorcycle battery. The cable broke in the middle with
what looks like a stress fracture. Cable was flexed many times, every
time battery had to be taken out or when battery had to be disconnected
for electrical tests or electrical modifications to motorcycle wiring.

Son contends it is the fault of soldering connectors onto cable, which
heat stressed the cable. I think it is copper work hardening when
flexing cable, thinking that heat if anything (maybe to low) would help
anneal copper.

Your opinion welcome.
cheers
T.Alan


Soldering the terminals didn't "heat stress" the copper however it is
possible that in soldering the cable solder wicked up the cable which
turned that portion of the wire into effectively solid wire thus
making the flexible portion of the cable shorter and contributed to
the work hardening of the cable due to flexing.

Annealing copper is usually done by heating it until it turns red and
either quenching it or leaving it to cool slowly. This is far above
the temperature necessary to soft solder copper wire. Thus the
question of "heat stress", if it exists, doesn't apply.

Try making the new cable longer and perhaps bending a loop into it to
allow more flexibility.

Regards,

J.B.