On Tue, 18 Dec 2007 04:31:48 GMT, Lostgallifreyan wrote:

wrote in news:a232ec67-c9bd-42ad-99f3-
:

why is 63-37 eutectic solder not universally preferred?

Probably because the gradual solidification makes dry joints less likely.
I'm not even sure it it does make them less likely, but I bet it does
because you're not relying only on ductility of a solid to maintain good
structure during thermal contraction. If the two metals in the alloy don't
solidify together, one can flow to fill pores that might form in the other,
or between the solder and the parts joined with it.

From my days at Mullard in the early 1960's, I seem to remember that
thermostatically controlled irons were not used, there were horrible large
things like an ice pick!

Multicore set the standard in the UK for many years and what they
suggested/supplied was what industry used. As everything was hand soldered then,
it had to be a solder and flux with as wide an operating temperature range as
possible.

Peter
--
Peter & Rita Forbes
Email:
http://www.oldengine.org/members/diesel
http://www.stationary-engine.co.uk