# Electrolysis, and cast iron.



## BIGTREV (Mar 1, 2017)

Electrolysis, and cast iron.
I been trawling the net for weeks, and totally confused as to whether electrolysis will harm/damage cast iron.
Has anyone tried it? if so what's your thoughts on it?
Thanks


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## bazmak (Mar 2, 2017)

I don't think you can successfully electroplate cast iron
I believe the carbon prevents sticking .Maybe someone more knowledgeable can clarify


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## abby (Mar 2, 2017)

What do you mean by electrolysis ? cast iron piston rings can be supplied chrome plated !


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## goldstar31 (Mar 2, 2017)

abby said:


> What do you mean by electrolysis ? cast iron piston rings can be supplied chrome plated !


 
He's getting 'rust removal' answers on another fora.:hDe:

Norm


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## BIGTREV (Mar 2, 2017)

Sorry, I should of added, it's to remove rust from parts of a mill I've bought
Thanks


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## RJW (Mar 2, 2017)

I've used electrolysis to clean rusted cast iron parts a few times which clean up a treat, and with no ill effects, care is needed though not to carry on the process too long or at too high a power setting because (anecdotally) it can cause embrittlement and microscopic cracks if things are overcooked,
I use ordinary washing soda crystals and a dedicated power unit, which has variable amp/volt adjustments, but people get away with using battery chargers and a car battery in the line ok,
Stainless steel is generally not recommended for electrodes if the electrolyte is going to be tipped down a drain, but this warning is probably more applicable to high volume operations where there's a fair risk of serious pollution,

Have a browse of this link, there are a ton of other links in there that'll keep you busy for a while,

http://www.mig-welding.co.uk/forum/threads/electrolytic-cleaning.12686/

John.


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## dnalot (Mar 2, 2017)

Hi

Removing rust is very easy and cheap. In fact it is effortless. Simply soak the part in vinegar over night and then rinse with water in the morning. The part needs to be cleaned of dirt and oils before you start. Save the vinegar for the next rusty part. 

Mark T


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## BIGTREV (Mar 3, 2017)

I'll need a lot of vinegar, to do the mill table 



dnalot said:


> Hi
> 
> Removing rust is very easy and cheap. In fact it is effortless. Simply soak the part in vinegar over night and then rinse with water in the morning. The part needs to be cleaned of dirt and oils before you start. Save the vinegar for the next rusty part.
> 
> Mark T


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## BIGTREV (Mar 3, 2017)

RJW said:


> care is needed though not to carry on the process too long or at too high a power setting because (anecdotally) it can cause embrittlement and microscopic cracks if things are overcooked
> http://www.mig-welding.co.uk/forum/threads/electrolytic-cleaning.12686/
> 
> John.


I've been using a 12v 6amp dumb battery charger, for doing steel parts, but concerned about hydrogen embrittlement when I do parts of the mill


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## mcostello (Mar 3, 2017)

Wonder what effect heat with a heat lamp would have on removing the Hydrogen?


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## bazmak (Mar 3, 2017)

Anyone comment on my post.Can cast iron be electro plated ??


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## Herbiev (Mar 3, 2017)

Why not use diluted phosphoric acid  I use a 5% solution for rust on cast iron


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## Parksy (Mar 3, 2017)

I've plated cast iron with nickel. Can be done.


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## Cogsy (Mar 3, 2017)

bazmak said:


> Anyone comment on my post.Can cast iron be electro plated ??


 
Yep, can be done but it's more difficult than other metals.,


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## BIGTREV (Mar 4, 2017)

I had read that  phosphoric acid will eat cast iron, but was going to try it on the inside the main body of the mill 
Thanks



Herbiev said:


> Why not use diluted phosphoric acid  I use a 5% solution for rust on cast iron


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## blanik (Mar 4, 2017)

Back on topic re Rust Removal from Cast Iron.  I have successfully used electrolysis to remove rust from Cast Iron.  According to the theory text books Hydrogen Embrittlement may occur with any ferrous metal that is subjected to an electrolysis type process, and some other processes.  Whether that Hydrogen Embrittlement will be a problem depends entirely on what the part is and how highly stressed that part is.

My background is in the Aviation Industry.  In that industry, because many of the ferrous parts used in aircraft are built as lightly as possible, and as a result are highly loaded in use,  Hydrogen Embrittlement is a big concern.

But for the types of parts that we as home shop machinists are likely to be encountering, Hydrogen Embrittlement is unlikely to be a problem.  That said, a highly stressed steel part in a model engine (i.e. a crankshaft) may suffer the effects of hydrogen embrittlement if it underwent some form of electrolysis - but then how likely are we to do that to a crankshaft ?

As far as the various methods of rust removal go - there are lots of techniques out there, and some have been mentioned in this thread.

Recently Lyle a.k.a. MrPete222 on his Youtube Channel has done a series of videos that he's called "The Olympics of Rust Removal".  There are three videos in the sequence, and this is the first video in the sequence.

[ame]https://www.youtube.com/watch?v=zCuQquR-rzo[/ame]

n these videos, Lyle tests ten of the most common home workshop techniques for rust removal.  

You may not agree with all of Lyle's test methodology, and you may not agree with all of his observations and findings - but I think that by watching his Olympics of Rust Removal videos, you'll get enough information to be able to make your own assessment regarding the benefits and otherwise of each of the Rust Removal processes.  I think that the videos also highlight some of the pitfalls of a few of the less controlled methods of rust removal.

Hope that info helps....

Regards,

Blanik


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## BIGTREV (Mar 5, 2017)

Thanks for that, I'm a big fan of tubalcain he talks my lanuage



blanik said:


> Back on topic re Rust Removal from Cast Iron.  I have successfully used electrolysis to remove rust from Cast Iron.  According to the theory text books Hydrogen Embrittlement may occur with any ferrous metal that is subjected to an electrolysis type process, and some other processes.  Whether that Hydrogen Embrittlement will be a problem depends entirely on what the part is and how highly stressed that part is.
> 
> My background is in the Aviation Industry.  In that industry, because many of the ferrous parts used in aircraft are built as lightly as possible, and as a result are highly loaded in use,  Hydrogen Embrittlement is a big concern.
> 
> ...


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## BIGTREV (Mar 27, 2017)

Hi. I'm back again, been busy removing paint with caustic soda and wallpaper paste, and rust from the mill, using electrolysis, how should l clean the rust from the feed screws, phosphoric acid, or electrolysis?
I'm also build a tank from old doors lined with plastic sheet, so l can put the main body of the mill in, and use electrolysis to pull rust from the knee dovetail on the front of the mill 
Thanks


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## Blogwitch (Mar 27, 2017)

BIGTREV said:


> I'm also build a tank from old doors lined with plastic sheet, so l can put the main body of the mill in, and use electrolysis to pull rust from the knee dovetail on the front of the mill
> Thanks



Use your large plastic/polythene garbage wheelie bin to do it in, if you have them where you come from. Resistant to almost anything.

John


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## BaronJ (Mar 27, 2017)

bazmak said:


> Anyone comment on my post.Can cast iron be electro plated ??



Hi Barry, 
I've used copper sulphate solution to copper plate cast Iron and steel parts prior to electroplating with nickel.  I know that they can be chrome plated as well but I've not tried chrome.


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## bazmak (Mar 27, 2017)

Thanks Baron,my aging brain seems to remember that its easier/necessary
to copper plate first before nickel or chrome plate.Thats why I asked the 
question about cast iron.I thought that the high carbon content was detrimental to plating


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## goldstar31 (Mar 28, 2017)

Barry, it's all in Matthew 6-19 but I think that your recollections may be from the horrendous shortage of plating metals during and after the War! After all, the cosmetic part of plating is  actually porous. Come to think about it, so is cast iron.

Kind regards

Norman


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## BIGTREV (Mar 28, 2017)

Blogwitch said:


> Use your large plastic/polythene garbage wheelie bin to do it in, if you have them where you come from. Resistant to almost anything.
> 
> John


I would if the bin was big enough, the mill is 4' 6" high
Cheers


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## BaronJ (Mar 28, 2017)

Surely you are not going to try de-rusting things without stripping the mill ?  The table needs to come off and the bearings on the leadscrews need checking and maybe replacing. 
Though I know of one person that used wet cloths and a metal plate to remove rust locally.  It looked very patchy afterwards.


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## BIGTREV (Mar 28, 2017)

BaronJ said:


> Surely you are not going to try de-rusting things without stripping the mill ?  The table needs to come off and the bearings on the leadscrews need checking and maybe replacing.
> Though I know of one person that used wet cloths and a metal plate to remove rust locally.  It looked very patchy afterwards.



It's stipped down, I've already done the smaller parts in a 45 gallon drum, I want to  to pull the rust from the dovetail, on the main body of the mill body. I've used caustic soda and wallpaper paste, to remove the paint already


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## bazmak (Mar 29, 2017)

As y mother used to say.Cant beat elbow grease.How about wire brushing
hand and machine.Scrape the ways etc etc.I an afraid your looking for an 
easy way.Shot/bead blast ?


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## BaronJ (Mar 29, 2017)

BIGTREV said:


> It's stipped down, I've already done the smaller parts in a 45 gallon drum, I want to  to pull the rust from the dovetail, on the main body of the mill body. I've used caustic soda and wallpaper paste, to remove the paint already



Aah, a picture says a thousand words.   I had visions of something much smaller.  

Could you not turn the base upside down and then immerse it in your drum, use a couple of wood supports across the drum top to stop it touching the drum whilst you electrify it.  You could use a wire brush on the rest of the base.  That should at least allow you to de-rust the knee dovetails.


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## BIGTREV (Mar 29, 2017)

BaronJ said:


> Aah, a picture says a thousand words.   I had visions of something much smaller.
> 
> Could you not turn the base upside down and then immerse it in your drum, use a couple of wood supports across the drum top to stop it touching the drum whilst you electrify it.  You could use a wire brush on the rest of the base.  That should at least allow you to de-rust the knee dovetails.


It's way too big and heavy, it stands 4'6" high, and they didn't worry how much cast iron they used when it was made, all assembled it weighs a bit over half a ton 
I've built the tank today, I'll post some piccies when I get it up and running.
Cheers


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## BIGTREV (Mar 29, 2017)

bazmak said:


> As y mother used to say.Cant beat elbow grease.How about wire brushing
> hand and machine.Scrape the ways etc etc.I an afraid your looking for an
> easy way.Shot/bead blast ?



I've never tried hand scraping, electrolysis cheaper than having it blasted + it pulls the rust out of the pits too. The only part I'm really looking to get clean, is the dovetail.
Cheers


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## bazmak (Mar 29, 2017)

For the dovetails if the rust is light then its scraping or wet/dry emery paper
If the rust is heavy then its a regrind


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## BIGTREV (Mar 30, 2017)

bazmak said:


> For the dovetails if the rust is light then its scraping or wet/dry emery paper
> If the rust is heavy then its a regrind



The rust on the dovetail is quite light, I'll finish it off with scotch brite.
Cheers


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