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Electrolytic rust removal


Hi all; I recently posted a couple of URL’s describing the process of
using inexpensive and common equipment to remove rust from tools and
steel articles. I’m afraid those URL’s are of no use to us. I can
no long find the there. Here’s the process entirely:

The main thing you need is a battery charger (automotive type).
They’re about $30 at an auto parts store, probably less at a place
like Harbor Freight or Wal Mart. Any source of DC current will do,
the higher the amperage, the better. In theory, a 9-volt "wall wart"
will do, but it would take a long time for any larger article. You
also need a plastic container, a scrap sheet of metal, preferably
stainless steel, and some baking soda. Fill the bucket with water
and add a handful of baking soda, about a tablespoon per gallon.
Washing soda works well too, if you can find it. Some folks use lye
in their electrolyte, but the soda is non-toxic. Prepare your sheet
metal anode. Stainless sheet works best (since it holds up longer),
but a flattened tin can will do in a pinch. Wire the POSITIVE to
the scrap steel. This will be the anode. You’ll want to keep the
clamp out of the solution, or it will eventually dissolve too. You
need to connect the article to be cleaned to the NEGATIVE side of
the charger, again, keeping the clamp out of the solution. You’ve
got to make a connection on a clean spot on the article, so you may
need to sand or grind through the rust at the point at which you
connect your contact. Put both the pieces (the article and the
scrap steel anode) in the solution, as close as possible but NOT
TOUCHING. The part being cleaned will begin to bubble. After about
two hours at 12 volts, six amps, you can take it out and examine it.
The part being cleaned, if originally badly rusted, will now be
covered with a black powder which you can wire brush off. Then
return the article to the solution for another 6 hours and you’ll
see all that is left of the rust is a little more fine black powder,
and the high spots may be getting shiny. At this point, you can
take the article out, rinse it off, wire brush it some more, and
then lightly oil it with linseed oil. Linseed oil is great for
tools, but be careful. . .rags soaked in it can spontaneously
combust, and I’ve seen this happen, so better put them in the burn
bin or bury them. If they’re cotton, you can put them in the
compost, everything in this case is organic, just don’t store them
in the house or garage. You can, of course, substitute any kind of
oil you’d like, but you’ll need to get that raw metal covered with
some sort of protection as soon as possible. This demonstration was
employed on a large steel punch, about 1/2 inch in diameter and 5
inches long. It was badly rusted, but not pitted. Even pitted
steel will clean. The pits will still be there, but they’ll be
clean of rust. Times for smaller articles could be significantly
shorter. Obviously, the less rusted a piece is, the shorter the
cleaning time. I don’t think that higher concentrations of baking
or washing soda will shorten the time, as it’s not the same as using
an acid or alkaline to clean, the soda is used to make the water
more conductive.

David L. Huffman