The Art Of Soldering

[Rob Strand]

It sounds like you ended up with the "purple plague", intermetallic compounds of gold and solder that do not have much strength and mechanically break down, causing open circuits.  If you had 150 microinches of gold, you could probably solder the component leads with no problem but if it was 50 microinches, you would be better off leaving the gold off entirely.

I can't remember the fine details since it was clear from the start it wasn't the way to go (I inherited the project).  The PCB manufacturer pretty much said outright that process had problems with soldering and the silvering would work.   

The problem started with me looking at a few dodgy boards and it soon became clear the soldering was a total disaster.  I think we kept the gold. 

Some time after that we did a complete redesign to modernize and fix some stuff.  That board end-up only having a switch contact and LED on one side and the connectors soldered to the other side.  I'm pretty sure we kept the gold on silver since the PCB company didn't have lead free HASL and silver immersion is quite bad for oxidization.