We all face the problem of rust somewhere along the line and the question is how to remove it or even recover some of the metal without doing any damage to the actual part itself
Electrolytic rust removal or Electrolysis
DO NOT USE STAINLESS STEEL or CHROME, The process breaks down the sacrificial anode and deposits Chromium in the water and the will end up in the local water so don’t do it, and it consider Hazardous Material. Also Hexavalent Chromium cause birth deformities etc so it’s nasty. The process also lets off Poisonous gases so JUST DON’T do it. Also putting some other Chemicals in the process will also perform electro plating for you but more about that in another build maybe. The process can also perform Electropolishing using Salt and propylene glycol (aka Anti-freeze), once again more about this LATER, and they are both more complicated.
Last warning, do smoke around this process unless you would like the by product, to induce some hair loss as the water is being separated into hydrogen and oxygen, not large quantities but enough. If there is loads of horrible looking foam on top, switch of the power and stirring the bubbles to pop them as this rusty messy foam has these by products trapped inside. The by product of this process bar the grease is from what I have research harmless, if you leave the bucket for a day, all the crap settles to the bottom, Siphon the water of and what you are left with is iron oxide, this you can filter through some building sand and toss the building sand in the bin. it’s not going to produce enough to have a acid mine water issue.
Some Theory: Rust is an electromechanical process, which means with the right elements we can reverse the process using electricity. The slower we do it, the better, but more amps is also good sometimes, but to much will just boil the water. Boiling the water is good for electropolishing but not for this. The slower the process, will actually recover some of the metal as there are two forms of rust or oxidation, one is a form of magnetite and the other is ferric oxide. If you want some more of the theory behind is go have a look here. Suffice to say we need Na2CO3 or more commonly know as sodium carbonate, closer investigation revealed it to be no more than Soda Ash, go figure. Also known as sodium carbonate, alkali of soda, washing soda, this is our electrolyte
Lastly, this process removes rust, dirt, grime, grease oil etc… so when it comes out of the bath, it’s 100% dirt free, so put some protective oil or Silicon on the part immediately once you have dried it off.
Ok, what do we need:
– A fused Power supply, anywhere between 1 and 10 amps max, else you’ll be cooking in a slow cooker. Battery charger works best in my opinion and I will tell you why later.
– copper wire
– sacrificial anodes, steel plate, bar rod etc, anything ferrous you don’t need, plate is ideal because it has a greater surface area
– A bucket or plastic container
– Soda Ash
– some rusty parts
– tooth brush
– fine wire brush (not essential)
– rust inhibitor
– some time!!!
Lets get started, if your container has a handle, remove that the handle.
Get the Copper Wire
Put a copper wire through the handle holes, this will become our Negative pole
put your sacrificial anode in the buck, and connect copper wire to this, don’t put this copper in the water, it will be eaten away, this is your positive anode.
throw about 6 tablespoons of soda ash into the bucket, less is fine to but around this amount is good.
fill with water
next take your rust part and wrap some copper wire round it and crate a hook to make over the Negative anode, make sure the the part will be totally submersed, don’t put it in the mixture yet. For obvious reasons it must not touch the positive when it goes into the mix
Now get some rusty Part to test with, this was mine, from a sliding bevel that was neglected
wire up all the rusty parts.
If you don’t have one get a Battery charger with similar specs to this one
Ok, connect the power to device, don’t turn it on just yet. I like a battery charger for two reasons, one it’s fused, two it’s got a volt meter. Now start putting your parts over the negative, put one or two parts on and turn on the power, if the voltmeter is half way then switch off and add another piece, when it is at about 2/3rd’s stop, main reason is as the rust falls off the conductive service is increased go past this point and the fuse will pop, don’t do this then you will pop your power supply.
IF your charger looks like this it’s too much, remove items. As the rust falls off the voltage will go up as the content gets better
Now wait, anywhere between 15 minutes to 48 hours depending on how much rust there is. Heavier rust 48 hours or so. This is a non-invasive process and does not damage the parts, it actually will convert some of the material into Magnetite, this is blue black colour the remains.
You will see the process fizzing, this is the rust coming off
If you don’t want your hands black use some gloves for the next step.
Cleaning the parts, once the process has run, wash the parts in hot water, can be cold but hot has an advantage that once you take the part and put it to dry, it will evaporate the water but rather not do this, dry the part as it will oxidise immediately otherwise. Spray on a rust inhibitor, marvel at the beauty (or at least I did)
More Info can be found here or just Google this, I didn’t invent the idea it’s the same process that takes place when using a rust converter / remover.
this is the next Major cleaning operation in progress at the moment, a buddy gave me some tools, but the had a few issues. nothing that cannot be fixed though.
Here is the router collet.
As a side though though you could get all these parts even cleaner if you used a wire brush, these parts are cleaned just with a toothbrush and a piece of Scotch Brite scourer. The black that you see is converted magnetite, so that is not an issue. In this part you can see the pitting from the rust, but there is no trace of rust after two days is very nice and clean.
Oxidation on the Aluminium parts was removed by media blasting. Here are the pictures of fully open and Fully collapsed, something the machine was in capable of doing. None of the collets collapsed before the process
This the rust sticking to the Anodes once completed. ANother bonus to this process will be it will strip and clean any grease or paint