You make an interesting point about “replenishment of
oxygen” being the trigger:
“The passivation process only works if there is a continuous supply of
oxygen to replenish the protective oxide layer as it gets damaged or is worn
off. Stainless steels especially the lower grades will corrode if one installs
aluminum or SS in an oxygen poor environment.”
As I recall, the AP cwts I received with a
purchase of a used mount, showed “staining” (assumed to be rust), only on the
flat end-FACES of those counterweights. The outer rounded surface looked fine.
If indeed my recollection of a few years ago is correct, that supports
your point in that the cwts were probably stacked tightly together, so there was
less access for oxygen to those inner surfaces for protective passivation,
compared to the outer sides.
Can anyone confirm that their rusted cwts were NOT
stained on their rounded surfaces? Indeed, the top and bottom cwt would be stain
free at the bottom and top of the stack of weights, but rusted where they
Doesn’t really matter since those (inner) surfaces are “out-of-sight”
anyway. To prevent rust staining anyway, one could place a toothpick as a spacer
between cwts to aid passivation, before locking them down on the
I polished them with some kind of cleaner I had at hand,
but it didn’t do much to remove the stain pattern. Now I know cleaners to try,
the next time.
One other thing – based on your comment. I suppose it
might be a poor idea to use any kind of automotive (bumper) chrome cleaner,
since theoretically it may also have a wax protective coating, which would
block the passivation process by sealing out the oxygen.