Rust removal with science.

Right, listen up folks. This here is probably going to be the most advanced and scientific post that ZD has ever seen which is pretty cool. Its also going to be quite long and I know some of you won’t stick with it as far as the science section but oh well.
As the regular readers will know, I have a collection classics and recently have acquired a new rust covered Alfa. Obviously these motors, (The Alfa so much more than any Triumph I’ve owned) have a certain element of rust and seized parts which need to be cleaned up and restored. I know there are so many techniques to do this but being the tight ass I am, I wanted a cheaper one. Couple that with my nature to mess about with projects I have developed a Electrolysis rust remover. Now this is not a new technique by far and is fairly documented, coin collectors use it regularly. I had read about the technique but didn’t really believe it would be as good as all the articles stated but still I thought I’d give it a go as it was cheap.

I have knocked together a basic prototype, not very tidy or advanced but it was functional enough to test the process. The MK1 is shown below. I didn’t clean the part in anyway prior to this or loosen any dirt. Basically it is made up of an old BBQ rack around the outside and then a conductive hook (made of a wire coat hanger) to hang the part on. The bucket is then filled with water to which I added 5 tablespoons of Sodium Hydroxide (Known commonly as Caustic Soda (Drain cleaner etc)). I then submerged the car part in the solution and attached the 13v power supply. This was positive to BBQ rack and negative to conductive hook. I’ve left it to work its magic and will report back afterwards.

As a note, if you plan on trying this, be incredibly careful with the Sodium Hydroxide as it is an extreme alkali and as such is highly corrosive.

###The Science###

I’m not going to copy the whole of a wikipedia entry for Electrolysis here, you can just that at that yourself but I’ll explain the basics of whats happening and how its happening in my setup. Electrolysis is the process of passing electrical current through an ionic solvent which causes chemical reactions at the electrodes and is used in material separation, hence the use here.

The only requirements are; an electrolyte, the Sodium Hydroxide solution. A pair of electrodes, in this case the BBQ rack and the car part and obviously an electrical current. The BBQ rack is known as the sacrificial anode which is connected to positive and the Car part is the cathode which is connected to negative.

The Sodium Hydroxide makes the water more conductive because of the ions in the Sodium and Hydroxide which help to carry the current. The sodium ions are positively charged and so move to the negative anode and the hydroxides are negative and so move to the cathode. This also explains why the corrosion moves, as this is a build up of oxides on the metal and oxide is also negatively charged.

As far as I understand, that’s about the top and bottom of it, simplified down some and applied to the setup I have. If anyone see’s a mistake here or thinks I have it wrong please feel free to let me know whats really happening.
Keep an eye out for the results either tomorrow or Friday.