The Shop > Finishing
Rust Removal
Darren:
Interesting John, I know not the answer...
I was thinking that Soda Crystals (Sodium Carbonate Na2CO3 ) is basically a mild relative to Caustic Soda (Sodium Hydroxide NaOH) Both made from common salt (Sodium Chloride NaCI) I believe via an electrolytic process. The process removes the Chloride and adds the Hydrogen from water.
The point is they are all some form of salts and there are many others.
My thinking is that the chemical softens the paints over a period of hours.The hydrogen formed at the cathode surface expands and pushes the paint off under pressure.
Because we have made the part negative no oxygen is formed on the part so even though it's immersed in salts the chemical elements needed to cause corrosion are not present.
This makes the process non invasive to the subject being de-rusted.
However, at the sacrificial positive anodes we have the oposite story. Oxygen is formed on the surface and a rapid evasive process takes place. If you want to rust something quickly and violently then this should do the trick.
It's worth remembering that while the current is kept flowing, your part (as long as it's at negative potential) will come to no harm as it's protected by hydrogen. Switch the current off and the oxygen in the water can now get to your piece and combined with the salts with soon start to attack your subject.
That's how I understand the process.....but I could be wrong as I failed chemistry badly.....
Darren:
Moving on a little I decided that doing half an item and then turning it over was not only taking double the time but also lead to a problem. When the object was turned over the bare side poking out of the mixture rusted at a phenomenal rate. I assume due to the evaporating water from below and and chemicals or gasses present.
The answer seems to be to totally submerge the part. I rigged up another container and used the round barrel to start off the process on the drill main column. As you can see the column is only half in. Therefore I will be rigging up another container tomorrow to do it properly.
Indecently, almost everyone, in the UK at least, has a suitable container for an item around this size. But you'll have to wait and see what I come up with.... :ddb:
So while those two were fermenting ( I hadn't "discovered" the big bucket at this point) I made a start on the drill stand which was in a bit of a sorry state...I'm using a small angle grinder with a flap wheel type disk.
Nothing fancy here just a good clean up ready for painting as I know the stand will get knocked about from experience.
All done, didn't come out too bad in the end
I like to be able move my tools about, esp if I need to make room, but mostly to make cleaning easier. This drill is heavy so I'm putting some wheels on the back of the frame.
The idea is that you can lift the front and all four feet will lift off the floor. It'll still be heavy but at least moveable single-handedly.
The wheels are not here to support anything, it still sits on all four feet.
John Hill:
Whoohoo! Be careful with your 'drill on wheels' Darren! If you lift the front it will not have to come up very high before it wants to tip over backwards and you will be hard pressed to stop it! (Now how would I know about such things?)
Darren:
Thanks for the heads up John....hadn't crossed my mind...... :doh:
It's top heavy init.....umm what to do now as I can see exactly what you mean.......
Darren:
I think the simple answer is to move the wheels further back to alter the balance position and centre of gravity.
I can do that.... :)
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