Electrolytic side effect

On Tue, 27 Jul 2004 20:32:47 -0500, Australopithecus scobis <[email protected]> wrote:

>Greetings,
> I recently got an old rusty #63 spokeshave on eBay. Used electrolysis to
>get off the thick rust. (I knew it was a beater when I bought it.)
>
> T'other day I was adjusting the depth of cut when the japanning stripped
>off the 'lever cap'. Scratched with a fingernail, and it all came off that
>piece. Red rust underneath. No prob, back in the pot and Bob's your uncle.
>
> Reason I posted is to gather opinions on this event. Do you suppose that
>wasn't Japanning, but enamel somebody sprayed on? Did my electrolysis lift
>the coat enough for water to creep in? The body's Japanning is beat up,
>but solidly attached where it remains.


My experience with electrolytic rust removal has been that it will lift the finish in any areas where oxidation has occurred below
the finish. I see that as a positive aspect of the process since it seems to expose areas of hidden corrosion.

I'll had fairly large areas of finish loosen when there is no apparent corrosion on the newly exposed metal. I don't have a
conclusive explanation of that effect. But, since I frequently leave the object in the bath for extended periods, it may be that
corrosion did exist but the process removed it. Or, IMO, a lower probability explanation is that the mildly alkaline solution is
loosening the finish. That is one reason I vigorously brush and scrub the object (plastic bristles and "scotch brite") in a fairly
strong solution of dishwashing detergent and hot water after the rust removal process. If any of the finish is loosened, that
generally removes it and prevents water entrapment under the loosened finish.

It is quite possible that the lever cap was repainted at some time in the past, but I don't think your experience is necessarily
proof of that.







Tom Veatch
Wichita, KS USA