[sdiy] preventing corrosion on bare traces

[Ingo Debus]

harry wrote:
> 
> The copper oxide that forms on the boards will protect the rest of the copper.

Hmmm... I've once seen a copper PCB trace corroded so badly that it
didn't conduct anymore. This was in an old electronic organ. The trace
wasn't interrupted completely, but there was loud rumble in the signal.
Soldering a wire across that trace fixed the problem.

> Spray is unnecessary unless you think it looks ugly. Rework will involve
> scraping
> the copper to fresh metal... or removing the spray anyway.

I've often used SK20 spray (Kontakt Chemie). It's not required to remove
the spray for soldering afterwards.

But it's not good if really high impedances are involved (like in sample
& hold circuits).

Ingo