Removing Rust with Electrolysis

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swamper
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Removing Rust with Electrolysis

Post by swamper »

evening all
having bought a set of brakes for the M im in the process of removing all the rust of them as they have been sat around for a good while.
now having found a few vids on youtube http://www.youtube.com/watch?v=gsBEv8HdvDI
iv followed the instructions to the letter im not getting any reaction taking place.... :head:
now for anyone that has done any heavy restoration i was wondering if they could shed some light on the problem ?
could it be the charger.......will a modem charger allow this process to take place.? 12v 8 amp
im using washing soda (sodium carbonate).
negative attached to part... positive attached to sacrifice part.
im still not not getting any hydrogen bubbles........any ideas :?:
the badness makes me do it...!

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si-forks
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Re: Removing Rust with Electrolysis

Post by si-forks »

Who was doing the video was it forrest gump does sound a good idea hope you can get it working

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Re: Removing Rust with Electrolysis

Post by siwilson »

si-forks wrote:Who was doing the video was it forrest gump does sound a good idea hope you can get it working

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swamper
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Re: Removing Rust with Electrolysis

Post by swamper »

yep get you....but the vid is just an demo....im not using graphite....just an old spade as a sacrificial part which is the positive so will attract the rust.
i want to learn how to do this rather that get someone else to clean them.
any other ideas ?
the badness makes me do it...!

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Dougblack
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Re: Removing Rust with Electrolysis

Post by Dougblack »

That doesn't seem right... The fact he didn't realise graphite IS carbon... And that the Soda is an electrolyte as opposed to a 'contaminant', and... Well... Least he didn't use a chloride 'I get that there smell of swimming' pools and that's good for clearing the old lungs out'.
1998 Montreal Blue Z3 1.9 (140Bhp E36 M44) "The Z".
swamper
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Re: Removing Rust with Electrolysis

Post by swamper »

iv been watching a few vids where they have used electrolysis ...heres another.....seems to get good results and its this process that im trying to recraite.
http://www.youtube.com/watch?v=y4yYF8gSHdA

now theres something im my set up that im missing ....but cant figure out what it is......im edging towards the charger not letting a charge to run through the solution...for some reason....safety feature maybe? :rtm:
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swamper
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Re: Removing Rust with Electrolysis

Post by swamper »

its a petty...i was looking forward to an easier way to clear the rust.....some of the vids the parts are actually bubbling
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Dougblack
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Re: Removing Rust with Electrolysis

Post by Dougblack »

They will bubble... If you put any two electrodes in a conductive solution it will produce a result, just working out what's reacting, the solution with the electrode, a reaction between the electrodes themselves with the solution as a catalyst... I think the guy needs a good look at the reactivity of his materials (I.e. what's 'stealing' what's oxygen and what's being oxidised etc... It's been a long time since schoolboy chemistry.. But I would think introducing the sodium (highly reactive) into the mix in the form of the sodium chlorite is just ending up with a sodium bicarbonate solution (as the salt), water as the solvent, and carbon dioxide as the gas, and as said, the alkaline solution is most likely stripping the oxide part of the iron not the electrolysis itself.

Like Na2CO3 (s) + H2O +(l) + C(s) -> NaHCO3 (s)+ H20 (l) + CO (g) on the side of the soda/water through electrolysis part?

Then the acid/alkali reaction between the rust an the soda.

(Been a long time since school chemistry as said)
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swamper
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Re: Removing Rust with Electrolysis

Post by swamper »

thanks guys...looks like its going to be the coke.........shame....i had wires going everywhere....looked great when the missus walked into the shed :shock:
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Robert T
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Re: Removing Rust with Electrolysis

Post by Robert T »

Dougblack wrote:Like Na2CO3 (s) + H2O +(l) + C(s) -> NaHCO3 (s)+ H20 (l) + CO (g) on the side of the soda/water through electrolysis part?

(Been a long time since school chemistry as said)
I'll say it has - one of your Na atoms seems to have gone on its holidays, 19 Hydrogen atoms have materialised from nowhere and I think I just died from Carbon Monoxide poisoning! :shock:

Cheers R.
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swamper
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Re: Removing Rust with Electrolysis

Post by swamper »

Zedonist wrote:
swamper wrote:thanks guys...looks like its going to be the coke.........shame....i had wires going everywhere....looked great when the missus walked into the shed :shock:
Did you scream "It's ALIVE!!!!"
it wasn't alive....other wise this thread would have gone a totally different way :D
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Dougblack
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Re: Removing Rust with Electrolysis

Post by Dougblack »

Ok ok, I said it was a long time... But still... I was trying to mean it'd make sense it was the electrolyte and the graphite playing electron football as opposed to the rust being reduced :(

I'm the IT geek, the brothers the chemist in the family.

*shame*
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Robert T
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Re: Removing Rust with Electrolysis

Post by Robert T »

Dougblack wrote:I'm the IT geek, the brothers the chemist in the family.
As am I. :nerd: :lol:

But I can still add up atoms. Notice how I carefully didn't try to point out the correct equation though. :wink:

Cheers R.
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Dougblack
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Re: Removing Rust with Electrolysis

Post by Dougblack »

Yeh I was toying to just go sodium carbonate + water + carbon etc etc... Hindsight eh... But anyways purely for kicks, or if anyone can...

What's gonna be the equation to notate the reaction between the aqueous washing soda and carbon under electrolysis and the reaction between the soda and the rust?
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Dougblack
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Re: Removing Rust with Electrolysis

Post by Dougblack »

And if the inherent reaction between the rust/soda is going to change the composition of the electrolyte to change the products of the electrolysis?
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swamper
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Re: Removing Rust with Electrolysis

Post by swamper »

^^^^ when you get there.....can someone tell me how to get the rust off......i want fizzing and lots of it... :D
the brakes are now sat in coke......but i want wires and dials and looks of surprise and me saying ..told ya !
the badness makes me do it...!

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Dougblack
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Re: Removing Rust with Electrolysis

Post by Dougblack »

Try conc. battery acid, then chuck some bicarbonate in, that'll fizz it's nuts off. Then use a wire brush on the rust :)
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Re: Removing Rust with Electrolysis

Post by swamper »

Dougblack wrote: Like Na2CO3 (s) + H2O +(l) + C(s) -> NaHCO3 (s)+ H20 (l) + CO (g) on the side of the soda/water through electrolysis part?

i think you should stick an E in their and liven things up... :bounce:

edit....just found this quote.
I found that my smart charger does not want to play nice for electolysis by itself. I had to buy a small car battery and hook it up in parallel with the charger before the charger would work consistantly.
the badness makes me do it...!

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Re: Removing Rust with Electrolysis

Post by gookah »

at least you don't have any hairs on them now.......
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Re: Removing Rust with Electrolysis

Post by John Wilson »

I feel as a graduate chemist working in a lab, that I should lay in with a definitive answer, but its been a long time since I did anything with what is a redox reaction. Rust is iron with extra oxygen attached to it so with the right environment and electricity to get the electrons moving, the oxygen can be removed to get back to the original iron. Although this sounds like a good idea, the rust is flaky and wont return to the underlying metal and will just end up as a sludge. I think there is the other oxide of metal involved (FeO as apposed to Fe3O4), which is not flaky and forms a harder coat.
I hope I'm not totally wrong in all this but I think that a more interesting concept is using the same principle to stop rust happening in the first place. If 2 different metals are clamped together, the more reactive one will get the oxygen atoms and prevent the other from rusting. In doing so, an electrical current will be set up between the 2 metals. This is what happens in galvanising where the zinc is sacrificed to zinc oxide rather than the iron. (I know theres also the effect of a physical barrier to keep the oxygen out. I seem to recall that some metal boats have a block of zinc attached to there hulls for this reason. Maybe a chunk on the z'3 bonnet would have the same effect and could have the added benefit of making the suspension a bit lower instead of resorting to expensive coil overs.
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Re: Removing Rust with Electrolysis

Post by swamper »

gookah wrote:at least you don't have any hairs on them now.......
i know...but i thought i'd leave it as it was :D
John Wilson wrote:I feel as a graduate chemist working in a lab, that I should lay in with a definitive answer, but its been a long time since I did anything with what is a redox reaction. Rust is iron with extra oxygen attached to it so with the right environment and electricity to get the electrons moving, the oxygen can be removed to get back to the original iron. Although this sounds like a good idea, the rust is flaky and wont return to the underlying metal and will just end up as a sludge. I think there is the other oxide of metal involved (FeO as apposed to Fe3O4), which is not flaky and forms a harder coat.
I hope I'm not totally wrong in all this but I think that a more interesting concept is using the same principle to stop rust happening in the first place. If 2 different metals are clamped together, the more reactive one will get the oxygen atoms and prevent the other from rusting. In doing so, an electrical current will be set up between the 2 metals. This is what happens in galvanising where the zinc is sacrificed to zinc oxide rather than the iron. (I know theres also the effect of a physical barrier to keep the oxygen out. I seem to recall that some metal boats have a block of zinc attached to there hulls for this reason. Maybe a chunk on the z'3 bonnet would have the same effect and could have the added benefit of making the suspension a bit lower instead of resorting to expensive coil overs.
so John the the "flaky" rust will not be removed ...but rather become "more separated" ie not reattaching .. hence the sludge
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Re: Removing Rust with Electrolysis

Post by John Wilson »

The rust will be removed, but it wont be transformed back to iron. Theoretically, it's like the oxygen atoms come off the iron and go onto the other electrode, causing that to rust in it's place. (I know its really about the electrons moving about but its an easier way to visualise it), but, because the rust is so flaky, it doesnt have the chance to transform back to solid iron and just goes into the solution as sludge. It just means there is less iron there than there was originally, rather than it being totally returned to it's original state.
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Re: Removing Rust with Electrolysis

Post by Southernboy »

A stiff wire brush, a "rust remover" coating, and a decent undercoat and paint...some filler if needed to smooth it out. :cheers
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Re: Removing Rust with Electrolysis

Post by swamper »

thanks John :wink:
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Re: Removing Rust with Electrolysis

Post by John Wilson »

Yes, you're absolutely right. I was forgetting we were talking about a graphite electrode and not a metal one. I think the gases coming off would be hydrogen and oxygen, just splitting up the water molecules. I was reluctant to claim expertise. I spend most of my time these days feeding solutions through expensive machines and analysing.computer data that comes out, and do less proper chemistry.
I think that although it's quite fun wiring up rusty metal to a power supply and pretend to the wife it has some value as she opens the windows to disperse the fumes, I think more boring remedies are better. Rather than just removing the rust with phosphoric acid based chemicals, I have always used something called trustran 23, which also combines with any remaining traces of rust to form a hard non-porous layer (I think it is a tannate if I have any credability as a chemist left). The trouble is that I bought a bottle about 30 years ago, and because you need so little of it, I've still got it, so I don't know how the company can survive on that level of sales. I havent seen it in the shops for ages and don't know if it's still available. There's probably similar products that can be bought. I guess when I bought it, profits were sky high caused by BL car owners franticly trying to stop their bodywork dissolving (happy days)
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Re: Removing Rust with Electrolysis

Post by huntert »

John Wilson wrote:I feel as a graduate chemist working in a lab, that I should lay in with a definitive answer, but its been a long time since I did anything with what is a redox reaction. Rust is iron with extra oxygen attached to it so with the right environment and electricity to get the electrons moving, the oxygen can be removed to get back to the original iron. Although this sounds like a good idea, the rust is flaky and wont return to the underlying metal and will just end up as a sludge. I think there is the other oxide of metal involved (FeO as apposed to Fe3O4), which is not flaky and forms a harder coat.
I hope I'm not totally wrong in all this but I think that a more interesting concept is using the same principle to stop rust happening in the first place. If 2 different metals are clamped together, the more reactive one will get the oxygen atoms and prevent the other from rusting. In doing so, an electrical current will be set up between the 2 metals. This is what happens in galvanising where the zinc is sacrificed to zinc oxide rather than the iron. (I know theres also the effect of a physical barrier to keep the oxygen out. I seem to recall that some metal boats have a block of zinc attached to there hulls for this reason. Maybe a chunk on the z'3 bonnet would have the same effect and could have the added benefit of making the suspension a bit lower instead of resorting to expensive coil overs.

The bits in boats are called "sacraficial annodes"
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Re: Removing Rust with Electrolysis

Post by John Wilson »

I dont know why they havent tried those anodes on cars. You would have to make sure there was a continuous conductive connection across all the body panels ( ie not completly insulated from each other by paint), and have a piece of zinc somewhere underneath (not on the bonnet -as my previous suggestion) resulting in permanent rust inhibition (until the zinc disappears).
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Re: Removing Rust with Electrolysis

Post by John Wilson »

Theres plenty of salt water around on our roads over winter- thats what causes the rusting in the first place. If the zinc is in an exposed place underneath and bolted directly to steel, that should be sufficient to set up a potential dfference.
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Re: Removing Rust with Electrolysis

Post by John Wilson »

Here's a z4 about to become amphibious when the tide comes in. A bit to much zinc on the left hand side, I think.
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Re: Removing Rust with Electrolysis

Post by pingu »

Re sacraficial anodes. I seem to remember from earlier days that cars went to negative earth so the positive pole of the battery was sacrificed instead of the many earth points. Any truth to this, or was I too busy sleeping during my lectures?

Re hydrolysis. I hope you were aware of the potentially explosive mixture of hydrogen and oxygen :shock:
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Re: Removing Rust with Electrolysis

Post by John Wilson »

Ah, perhaps this is the answer to rust prevention. You use the battery instead of the zinc to set up the potential difference. So by joining up all the panels together in one huge earth terminal, the positive terminal will be sacrificed in place of the panels rusting. The battery terminal may have to be replaced at intervals, but it's better that than a rusting panel.
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Re: Removing Rust with Electrolysis

Post by whiteminks »

Just get some rust eater and a wire brush or take it to a body repair shop and get it prepared and resprayed ;-)
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Re: Removing Rust with Electrolysis

Post by John Wilson »

That's just a ridiculous comment. Don't you realise I can NEVER find the wire brush in my place.
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Dougblack
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Re: Removing Rust with Electrolysis

Post by Dougblack »

So... Maybe we should get car manufacturers to just swap the polarity of the electrics?

I believe on old Landrovers try used a positive 'earth', and didn't this change the way that vehicles rust?

I always wondered about sacrificial zinc and why didn't they use it, but then don't think manufacturers want cars to last forever!

Oh we'll... A stuff brush is all it is!
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Re: Removing Rust with Electrolysis

Post by John Wilson »

We wouldn't have to change to a positive earth. It's already the right way round. The only thing that needs doing is making sure all the panels are able to have electricity floring between them and are not insulated from each other by paint or anything else. Then it will only be the positive terminal of the battery that will preferentially rust
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Re: Removing Rust with Electrolysis

Post by swamper »

12 hours on charge.....iv changed the sacrificial part for a bit of axle stand.........and put a battery in the loop to keep the charger going.
and heres the results.......
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it does work....its going to be left a little longer and then cleaned off.... will post the results :wink:
the badness makes me do it...!

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Re: Removing Rust with Electrolysis

Post by John Wilson »

I always wondered how they made iron bru
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Re: Removing Rust with Electrolysis

Post by swamper »

it made from girders ... :D
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Re: Removing Rust with Electrolysis

Post by Dougblack »

That looks PROPER orange! Did u drop a tube o copper grease In there?.... Hang on... Don't Ford paint then ST Focus' with that stuff??
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Re: Removing Rust with Electrolysis

Post by swamper »

yep...or puke green.. :colourful:
the badness makes me do it...!

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Re: Removing Rust with Electrolysis

Post by swamper »

first parts are now coming out of the coke bath

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the badness makes me do it...!

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Re: Removing Rust with Electrolysis

Post by Southernboy »

Powder coated is best...they give them a good clean with the sandblaster first...It'll get rid of any rust etc etc and seal them up nicely...Nipple pink is in right now... :D
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Re: Removing Rust with Electrolysis

Post by swamper »

Zedonist wrote:Looking good mate, get em painted or powder coated quickly as the surface will be active and start to rust following your pickling process.

How bad were the fumes if any?
i did it outside in the end so had no problems...and tey the rust starts to come back right away so i'll get them coated :wink:


nipple pink ..... :D
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Re: Removing Rust with Electrolysis

Post by pete59 »

that looks good swamps,whats the bigger bit look like?
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Re: Removing Rust with Electrolysis

Post by swamper »

sorry Pete thought i'd added it.
the caliper is still in soak....but this is how it started off

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and this is its current condition

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as you can see there a large improvement
the badness makes me do it...!

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