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The main thing you need is a battery charger (automotive type). Any source of DC current will do, the higher the amperage, the better. In theory, a 9-volt "Wal Mart special" 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. 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 bare metal 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 alkali to clean, the soda is used only to make the water more conductive. David L. Huffman |
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