De-rusting

[alanworland]

Having read the article in last months Practical Classics on de rusting using soda crystals and a battery charger, I gave it a whirl on an exhaust manifold.
Result was fantastic, it even removed the rust from inside with no extra electrodes!
58p for a bag of soda crystals. Highly recommended.

[aupickup]

can we ask how its done

[alanworland]

Mix up a 1% solution of soda crystals in a plastic bowl/bucket/wallpaper tray.
Connect the negative supply from your battery charger to your rusty component in the solution.
Conect the positive supply from your battery charger to one or more sacfificial steel plates also in the solution.
Turn on battery charger (it will draw anything up to about 6 amps) and sit back with the knowledge that the rust will be removed from your component!
My manifold took about 24 hours, I took it out and washed it in hot water, which dried quite quick. I then sprayed it with VHT paint while it was still warm!

[luridhue]

I remember my dad doing this with his old mini's. Basic Electrolysis, the sodium bicarbonate merely acts as an electrolyte allowing the electrons to easily transfer through the water and increase the speed of the process. If you use lots of power (I think my dad hooked up a welding unit of some sort although it could have been any transformer -it was a long time ago) and really up the speed. Although you'll get hydrogen coming off the negative side and oxygen off the positive side.... rocket fuel!!! hehe.

Thinking about that, if you're leaving it for 24 hours or so then keep it in a ventilated area as a substantial amount of hydrogen and oxygen would be produced. And for added safety keep clear of naked flames.

Careful with the salt used as things like caustic soda would obviously damage things (because it is so corrosive.) but almost any salt can be used for this (although table salt would be corrosive and let off chlorine gas.

[alanworland]

Sodium Bicarbonate?
The article suggested soda crystals or washing soda - bought mine from Tesco. Or is this the same as the bicarbonate?

[luridhue]

I'm not sure what 'washing soda' or 'soda crystals' refer to. Does it have anything further on the packaging?

[bmcecosse]

Washing soda = sodium carbonate

[luridhue]

Washing soda = sodium carbonate

Oooh, that tastes good on chips... (disclaimer... that was a joke, don't put on chips!)

Isn't Sodium Carbonate the powder you use to strip the flesh off skeletons of dead animals? (or is it something like sodium carbonate decahydrate (or something with a stupid name))

I got in trouble when I was younger for boiling up a dead frog... keep boiling until nothing but skeleton is left and then reassemble... not surprising I went to uni and read Palaeobiology (fossils and rocks!)

[Luxobarge]

Sodium Bicarbonate = baking powder, don't use this!
Sodium Carbonate = washing poweder, this is the fella, got mine from Asda no problem.

I'm about to try this technique in the next few days in the "Wheel restoration" thread in "Bodywork" - I'll take lots of photos etc., I'm encouraged by your findings, I hope I get as good results.

Cheers

[luridhue]

Sodium Bicarbonate = baking powder, don't use this!

Sodium Bicarbonate definitely does work in a redox electrolysis reaction. You only need a salt that will increase the conductivity of water.

[Luxobarge]

Sodium Bicarbonate = baking powder, don't use this!

Sodium Bicarbonate definitely does work in a redox electrolysis reaction. You only need a salt that will increase the conductivity of water.

Yes, sure it works, as do loads of salts, but many give off gases that are undesirable - I'm not sure what gas Sodium bi-carb gives off, but I'm sure I read somewhere that it's either undesirable or downright dangerous - maybe someone knows? Any chemists here?

Started my electrolysis bath today, see here: http://www.morrisminoroc.co.uk/index.ph ... 2&start=30

Cheers

[luridhue]

Sodium Bicarbonate should not give off any gas, that is why it is used for electrolysis reactions in schools as it is very safe and non caustic. If you use table salt you'll get chlorine

Also, if you mix toilet cleaner and an oxygen based 'bleach' you get copious amounts of oxygen, all useful things to know as a child

[Luxobarge]

Sodium Bicarbonate should not give off any gas, that is why it is used for electrolysis reactions in schools as it is very safe and non caustic. If you use table salt you'll get chlorine

Also, if you mix toilet cleaner and an oxygen based 'bleach' you get copious amounts of oxygen, all useful things to know as a child

Oh, right, cool - didn't know it was also safe/inert. Mind you, both are cheap and easy to get, so I don't suppose it matters all that much.

Yeah - I remember stuff like that from school, we had a great chemistry teacher who would spend the last week of summer term showing us loads of "how to blow things up" experiments - one of them being to electrolyse water, and capture the gases in a baloon. Being as the gases were a perfect hydrogen/oxygen mix, it didn't half go off with a bang when we lit it with a flame - we had to do it at the end of a long window-pole stuck out of the window, my ears were still ringing hours later!

Pardon??

[luridhue]

Our chemistry teacher was a real drunkard, but was a great guy, really engaging and he started up a chemistry club... an excuse to do dangerous experiments outside of class. I remember making explosive soap or playing with acids. We also went on a chemistry club trip to wales. I think if it were not for him my passion in science would have been destroyed when in my teens.

[minor_hickup]

I've been doing this for a while now, and I've always found it very effective, especially on things like manifolds where you cannot get inside. But I fear many people do not clean off the items well enough after de rusting them, a good wire brush to remove and deposits and de grease is still necassary.