On 7 Jan 2006 07:41:48 -0800
" wrote:

Thanks for trying to assist but I know about sulphuric acid.
.............
It's sodium carbonate dissolved in water in plastic container. Connect
a car battery to the object to be de rusted and the other wire to a
stainless steel anode in the water.


OK, so you are planning to use a solution of sodium carbonate as an
electrolyte and use the battery to power the removal of Ferric Oxide
and Ferrous Oxide (I can remember which is normal rust, probably both).

Seems plausible, I'm not sure if there is a better cost effective
electrolyte. This article suggest you may have a point:

http://www.stovebolt.com/techtips/ru..._derusting.htm

Note the precautions in the article and also keep the soldium carbonate
solution well away from the battery :-)

R.