MFW June 2013 - Page 6

The process. Mix up in a plastic container washing soda and warm water (about 75-100 grams per litre) Clean up one end of the electrode (I use a piece of rebar) The positive lead goes to the end of this. Don’t submerge the charger clamp, as it will get eroded. The rusty work must be submerged, and the negative lead goes to this. You can submerge this clamp without problems. You might need to scrape off a little rust to get a good contact. Make sure the rusty part and electrode cannot slip and touch each other. Switch on the charger. If the current is too high on the chargers meter there are a number of things you can do to reduce it; • • • Increase the distance between the rusty part and the electrode. Dilute the washing soda solution by adding more water if you have a 6/12 volt charger, change it to the 6 volt setting If it’s working OK, bubbles of hydrogen and oxygen will come off the electrodes. The time to clean a part will depend on the current, the area of the rusty part and just how rusty it is. Keep checking it, but I find 1 –8 hours is typical Then use fresh water, a plastic or maybe a wire brush to clean it up, then oil or wax it, or the rust starts all over again, and all too quickly ! So, how does it work? Well in Picture top right you can see an old rusty lathe tool rest, after 3 hours in the bath, it comes up like Picture lower right. One warning, it is possible that metal cleaned this way may be subject to hydrogen embrittlement. This has never worried me, but be aware that it can cause cracking in some high-strength steels, For instance it would be unwise to de-rust, say, critical axle parts this way. Now, for a brief mention of some higher