On 11/6/2012 8:36 PM, David Beierl wrote:
> solder is not load-bearing.

That's a myth. There's a reason they make acid core (and low temp
silver) solder.

Common 60/40 has a tensile strength of around 535 kgf/cm�, 3.5% silver
solder, about 580. Not that much difference. The important thing is to
ensure the joint is properly wetted, and keep the joint stationary while
cooling. Using a eutectic alloy (63/37) almost eliminates the issues
cause by movement.

I suspect the "non-mechanical" part comes from people making 60/40
joints and allowing them to move while in the plastic zone.
Mechanically, a proper soldered joint of equal overlap (and no twist)
will be stronger than a non-soldered WU splice with stranded wire, so it
should be apparent where the strength comes from. WU splices are really
only effective on solid wire, which shouldn't ever be used in an
automotive environment.

That's not to say that a soldered WU splice isn't the best thing to do
in most cases.