Mike Pass
Supporter
I have been doing some trials of this process and thought this might be of interest as we often have rusty iron or steel parts to clean up which my be really crusty, very intricate or have areas which are hard to get at. I did a bit of research and then gave it a go.
The chemicals and equipment are mostly readily available. You will need a plastic non conductive container big enough to take the item you want to de-rust; some washing soda; a 12volt battery charger; some iron wire and a carbon rod.
The washing soda can be bought cheaply from the washing powder/detergent aisle at the supermarket. Dissolve a good cupful (or two) of washing soda in some hot water from the tap and stir until dissolved. The washing soda makes the water conduct electricity. The washing soda is not used up by the process and can be used again and again. The solution is alkaline and feels soapy so wash it off your skin in lots of clean water.
Iron wire I found by stripping the plastic coating from garden wire or scraping the coating off wire coat hangers. Don’t use stainless or galvanised wire.
The carbon rod is the only item that is not usually to hand, but I got mine from on Ebay from China. Buy the biggest you can.
The 12 volt battery charger I used was a cheap basic 6amp one but any will do the job. More amps does the job quicker.
Connect the carbon rod by wrapping the iron wire round it tightly and put it in the washing soda solution, keeping the connecting wire out of the liquid and connect it to the red wire from the battery charger which is positive and this is then the anode +ve.
Connect the part you want to derust to a piece of the iron wire making sure that it makes a good electrical contact. This is then connected to the black wire from the battery charger which is the negative and this is then the cathode –ve.
Switch on and you should see bubbles of gas at both the carbon rod and the rusty part. These gases are hydrogen and oxygen caused by dissociation of the water molecules which can build up and are explosive so do this outside or in a well ventilated area. Oxygen is produced at the anode (red) +ve and hydrogen at the cathode (black) –ve. Naked flames or sparks are obviously a bad idea.
The current travels in a straight line between the two electrodes so you will need to move the carbon rod around the part to even out the derusting over the part. Make sure the carbon rod does not touch the part and short out the battery charger. Leave it running until you see the red rust disappear or chang to black. When ready switch off and remove the part and give it a good scrub with a stiff brush, scouring pad or wire wool to remove the black residue (iron oxide). The red rust has been converted from red rust to black iron oxide. If any rust remains repeat the process until all the red rust is gone. Badly rusted parts will still have pitting where the rust has eaten into the metal. The metal will now need some protection to stop it going rusty again.
Points to note:-
Use only iron or mild steel wire to connect the part. Not copper, stainless or galvanised.
On the carbon rod side keep the iron wire out of the liquid or it will get messy with red crud.
Iron or steel can be used instead of the carbon rod but it will get really messy with the creation of a load of rusty sludge. Very messy!
The carbon rod does not get used up and keeps everything nice and clean. The carbon rod and the washing soda can be used over and over again as they don’t get used up.
DO NOT use stainless steel wire or a stainless steel anode as some very nasty toxic chemicals will be created.
For large parts you can use several carbon rods connected in a ring around the part.
Some photos attached of the set up and some before and after pics. After derusting the items were treated with cold gun blue and wax.
Cheers
Mike
The chemicals and equipment are mostly readily available. You will need a plastic non conductive container big enough to take the item you want to de-rust; some washing soda; a 12volt battery charger; some iron wire and a carbon rod.
The washing soda can be bought cheaply from the washing powder/detergent aisle at the supermarket. Dissolve a good cupful (or two) of washing soda in some hot water from the tap and stir until dissolved. The washing soda makes the water conduct electricity. The washing soda is not used up by the process and can be used again and again. The solution is alkaline and feels soapy so wash it off your skin in lots of clean water.
Iron wire I found by stripping the plastic coating from garden wire or scraping the coating off wire coat hangers. Don’t use stainless or galvanised wire.
The carbon rod is the only item that is not usually to hand, but I got mine from on Ebay from China. Buy the biggest you can.
The 12 volt battery charger I used was a cheap basic 6amp one but any will do the job. More amps does the job quicker.
Connect the carbon rod by wrapping the iron wire round it tightly and put it in the washing soda solution, keeping the connecting wire out of the liquid and connect it to the red wire from the battery charger which is positive and this is then the anode +ve.
Connect the part you want to derust to a piece of the iron wire making sure that it makes a good electrical contact. This is then connected to the black wire from the battery charger which is the negative and this is then the cathode –ve.
Switch on and you should see bubbles of gas at both the carbon rod and the rusty part. These gases are hydrogen and oxygen caused by dissociation of the water molecules which can build up and are explosive so do this outside or in a well ventilated area. Oxygen is produced at the anode (red) +ve and hydrogen at the cathode (black) –ve. Naked flames or sparks are obviously a bad idea.
The current travels in a straight line between the two electrodes so you will need to move the carbon rod around the part to even out the derusting over the part. Make sure the carbon rod does not touch the part and short out the battery charger. Leave it running until you see the red rust disappear or chang to black. When ready switch off and remove the part and give it a good scrub with a stiff brush, scouring pad or wire wool to remove the black residue (iron oxide). The red rust has been converted from red rust to black iron oxide. If any rust remains repeat the process until all the red rust is gone. Badly rusted parts will still have pitting where the rust has eaten into the metal. The metal will now need some protection to stop it going rusty again.
Points to note:-
Use only iron or mild steel wire to connect the part. Not copper, stainless or galvanised.
On the carbon rod side keep the iron wire out of the liquid or it will get messy with red crud.
Iron or steel can be used instead of the carbon rod but it will get really messy with the creation of a load of rusty sludge. Very messy!
The carbon rod does not get used up and keeps everything nice and clean. The carbon rod and the washing soda can be used over and over again as they don’t get used up.
DO NOT use stainless steel wire or a stainless steel anode as some very nasty toxic chemicals will be created.
For large parts you can use several carbon rods connected in a ring around the part.
Some photos attached of the set up and some before and after pics. After derusting the items were treated with cold gun blue and wax.
Cheers
Mike
