Getting rid of rust can cost a fortune in chemicals but if you have the time and can fully submerge the item to be de-rusted, here is a cheap way to do it. Submerge it in a black molasses and water solution. 1 part black molasses to 9 parts water. I have 40 litres of the stuff mixed up.
Where I used to work on Norfolk Island (in the South Pacific, halfway between Australia and Fiji - the place where the majority of the descendants of the mutineers from the Mutiny on the Bounty live), we had a 200 litre (44 Imperial gallons, 55 US gallons) drum mixed so we could dip big stuff. Like any small island, because of salt spray, rust is a real problem over there.
I know it sounds unlikely but these three pictures are of a bit of rusty steel I found and treated. The first is the steel as found, the second is with part of it cleaned up with a wire brush in an electric drill. The third photo shows the effect after a few days in molasses and water. Note that it is so clean after washing off the muck that it is already showing orange rust appearing after a few minutes exposure to the air.
Really severe rusting will need a week or so in the solution. I recommend removing the job after a few days and wire brushing to remove the loosened scale, a quick hose down and return to the pot for another go. It is essential that the steel is fully covered. Unprotected steel will corrode very badly at the air/solution interface where it come out of the solution. Note: Some alloys e.g., zinc will be severely corroded by this stuff so keep it for iron and steel only or test it first.
I bought 5 litres of blackstrap molasses (stuff they feed horses) from my local feed and produce store in Penrith (suburb of Sydney). It is quite cheap.
Email Ron Beckett with comments about this site
This page was last updated 7th January, 2005