dunno who wrote it, it could be me. It was in Dutch and I translated with Google in to English .
I did not edited it, so perhaps here and there it's funny English !
But you get the idea I suppose.
Electrolytic derusting
If you are looking for an effective, relatively safe and above all cheap way of removing rust, try electrolytic rust removal. That may sound complicated, but it is actually very simple and it does not damage the surface. In short, it amounts to immersing the rusted metal in an electrically conductive solution of soda in water. The positive clamp of a battery charger (red) is connected to an iron electrode and the negative clamp (black) to the part to be rusted. When the charger is turned on, a reaction occurs at the boundary of the metal and rust. This loosens the rust, so that it can easily be brushed off. The underlying layer of metal is not affected, only the rust comes off. Of course, the appearance of the metal underneath does not improve, so all the pits that are in it remain, but all rust is removed. You can continue to use the water/soda solution, although you will occasionally have to replenish the water that evaporates or is split by the electrolysis.
Important safety precautions
The solution is alkaline (alkaline) and can irritate the skin and eyes. Always use goggles and rubber gloves when working with the solution and rinse everything well afterwards.
The charger must be shielded from the solution. Make sure you position the battery charger in such a way that no water / soda solution can be tampered with. The 6/12 volt connections of the battery charger are fairly safe but it is possible to get a shock if you keep your hands in the soda solution or touch the electrodes while there is voltage on them. Turn off the charger to avoid that risk.
As a result of the electrolysis, the water will split into its components, hydrogen and oxygen. Therefore, work in a well-ventilated environment and avoid any kind of ignition, such as cigarettes or sparks from the battery terminals. (The combination of hydrogen and oxygen gas, as released during electrolysis, is explosive.)
Supplies : Water - Soda - A battery charger
Rebar for the anode (cheap and the anode will eventually be eaten away)
A plastic oil barrel or waste bin that is large enough to put your parts to be rusted.
Procedure
Make the cleaning solution by dissolving 1 tablespoon of soda per 5 liters of water. Make sure the soda crystals are properly dissolved. If necessary, dissolve them first in a little warm water.
Regularly clean the anode(s) slightly. They don't have to be spotless, but at least enough to make good electrical contact.
Connect the positive clamp of the charger to the iron anode. Immerse the anode in the solution, but make sure that the clamp of the charger is not submerged, because then it will eat away. The iron anode will also be eaten away, but that will be slow. If you want to clean a large piece, you need several anodes, because otherwise the side pointing to the anode will be cleaned much better than the other side. You then place several anodes in such a way that the workpiece is surrounded and you connect the anodes to each other.
Connect the negative clamp of the charger to the workpiece to be cleaned and immerse it. Here it does not matter whether the clamp is also under water, because this pool is not eaten away. Just make sure that the workpiece and the anode do not touch each other, because then you will get a short circuit. Keep a minimum distance of about 5 cm.
Turn on the charger. If the current is too high, you can do a few things to bring it down:
Increase the distance between the workpiece and the anode
Dilute the solution by adding water to it
If you have a 6/12 Volt battery charger, set it to 6 Volt.
In the pictures below you can see a plastic waste bin that I use for cleaning. The electrodes are fastened by the wall with straws and are connected to each other along the outside. Make sure you do not fill the container so that the slings are also flooded, otherwise they will also be affected and you will not be able to loosen them to be able to replace the anodes if they have been eaten away too much.
When everything is connected, you will see small bubbles forming, oxygen at the anodes and hydrogen at the workpiece (the cathode). Over time, a layer of brown sludge will appear on the surface. The time to clean a piece depends on a number of factors:
The size of the workpiece
The amount of power
The degree of rust formation
If necessary, you can leave the entire setup on overnight. Preferably do not do this in an enclosed space. (See safety precautions above). It may be necessary to remove the workpiece from the solution in the meantime and brush off the sludge that has arisen on the surface.
To rust several small things at the same time, I use a metal container, which I put on top of a piece of PVC pipe that is upright in the container. By attaching the battery clamp to the tray, the small parts are all powered and thus rusted.
