[Johny]

Originally Posted by JBat

Good post Larry.

Just one nit to pick, galvanic corrosion occurs with the yoking of dissimilar metals, as in a sacrificial anode system used in cathodic protection. The metals must have different electrical potentials for there to be a flow of current. In gas pipelines, for instance, we attach magnesium galvanic anodes to steel pipelines. Current flows from the cathode (the pipeline) to the anode (the magnesium) through the metallic path (the wire connecting the two), then through the electrolyte (the dirt) back to the cathode. The mag corrodes and the pipe doesn't is a simplified way to describe it. The process whereby the corrosion is dramatically slowed is called polarization. Basically, the whole thing is a battery.

What you describe is more in line with atmospheric corrosion. In the absence of any of the four components of a corrosion cell, anode, cathode, metallic path or electrolyte, you cannot have a galvanic system. Since the watch isn't submerged in the electrolyte, and there aren't dissimilar metals involved, it's atmospheric corrosion.

hi j welded a few anodes on in my time.