[R-390] Solder

[Tisha Hayes]

Solder is interesting. When I was doing the QC/QA thing a bunch of
years ago we were using a eutectic blend with silver in a wave
soldering machine. After a while the solder would get "crapped up" and
wetting and wicking would become "odd". The joints were no longer
shiny with the concave little cusp you would see on a PCB solder joint
where the component lead would make a 90 degree angle with the pad.

It took drawing samples out of the wave soldering machine (including
samples of some unidentified solids in the base of the machine) and
sending them to our research center for analysis. What we found was
that the solder mixture deteriorated from copper contamination. Even a
fraction of a percentage too much copper would make what was left in
the tank nearly useless unless we balanced that out with a little bit
more silver.

The elemental analysis was a really good read. Small percentages of
gold, copper and a bunch of other metals.

-- 
Ms. Tisha Hayes/ AA4HA
-
"Life isn't about how to survive the storm, but how to dance in the rain"