Homebrew PCBs

At 15:33 06/06/16, Stefan Trethan wrote:
>It [silver] will oxidize but silver oxide should be conductive, right?

Resistivity
Copper: 1.7E-8 Ohm-m
Silver: 1.6E-8 Ohm-m
Gold:   2.4E-8 Ohm-m
Silver Sulphide: 1.5E-3 to 2.0E-3 Ohm-m
Silver Oxide: 1.0E9 Ohm-m

So that's a 1.6E17 ratio - not my idea of a conductor.
(Numbers from an unauthoritative but well-argued Internet source)

However, in my locale, silver tarnishes to a brown/black, which
is probably silver sulphide (silver oxide is white or greyish).

This is only about 5 decades worse than the metal.

Still enough to cause unreliability in my college computer room's
old 10Base2 network with its many silver-plated BNC connectors.

To locate the bad ones, I used to terminate a section with a
shorted terminator and impose a small test current and
listen for the AF noise across the current limiting resistor as the
cable was handled. Usually, some contact cleaner and several
re-insertions would restore service for a few months.


Regards, LenW