An alternative to electolysis for rust removal

[derekcohen]

I have been following discussion on other forums about the use of citric acid as an alternative to electrolysis for rust removal. It sounds very promising. I have not attempted it myself as yet (not enough "rust" to warrant it), so all I can go on are the reports to date that it works as well as, if not better than electrolysis. Plus it is much simpler to apply, cheaper (in terms of equipment), and less poluting. You do not even have to remove timber - just coat this in xax.

Powdered citric acid can be obtained from pharmacies, health food shops, and even supermarkets.

One formula is: one heaped tablespoon of citric acid, 10 tablespoons of water,
one drop of dishwashing liquid, and a teaspoon of denatured alcohol.

Use a foam brush to apply the solution and expose it to the air and evaporation. Renew a couple of times over a 2-hour period. Use a paper towel to remove the resulting sludge and then buff dry with a dry paper
towel. Neutralized with water and dried off.

Give it a go and report on your results.

Regards from Perth

Derek

[simon c]

Hi Derek,

Sounds a great idea. Citric acid is a very under-appreciated product. I think it's something to do with teh fact that it sounds like you're just using lemon juice.

Citric acid is a very common cleaner particulary around bathrooms as it is designed to remove scale and rust. The cleaner CLR (Calcium, Lime, Rust) uses citric acid as one of its active ingredients. The reason that most industrial bathroom cleaners smell of lemons is not because that add lemon fragrance to make it smell nice but because citric acid has a natural citrus smell. It can also be used as a concrete etcher as an alternative to hydrochloric acid (I think teh White Knight product uses it). It is a lot less dangerous than some of teh stronger acids and is more "natural" on the environment.

Simon

[silentC]

Derek, could you clarify how it's less polluting?

Electrolysis causes no pollution that I'm aware of, unless it's the pollution caused by the creation of electricity at the power plant? You mix up a tablespoon of washing soda in a bucket of water and that's the only chemical required. I've been using the same bucket of water for a year now, topped up occasionally because of evaporation.

I'd also challenge the idea that it's easier to apply. Attaching a wire and dropping the object in a bucket is as easy as it gets.

[derekcohen]

how it's less polluting?

SilentC

I'm not really referring to gas or residues, just the smell, which has been my experience. Probably the main difference (so I'm told) is the difference in the colour of the metal afterwards. The citric acid does not leave the metal grey and "dead" as electrolysis tends to do.

Regards from Perth

Derek

[silentC]

Electrolysis converts some of the water into hydrogen and oxygen. I'm not a chemist but perhaps ozone or hydrogen sulphide is being produced, both of which smell. The most important thing in electrolysis is to make sure it's done in a well ventilated space, because aside from the smell, the combination of hydrogen and oxygen is what powers the space shuttle.

Electrolysis doesn't sacrifice any good metal, where most other treatments do, so I suppose you would have to use a bit of caution with citric acid. It would be interesting to see a scientific study.

[IanW]

I have been following discussion on other forums about the use of citric acid as an alternative to electrolysis for rust removal.

Give it a go and report on your results.

Regards from Perth

Derek

Derek - I tried wot you said. Soaked myself in pure lemon jiuce for an hour, then tried reading an old text-book.
Nope, just as rusty as ever!!
Avagooday

[rev]

I've been thinking of getting one of those Enjo or Sabco microfibre mits for tarnished metal to do the regular cleaning of cast iron surfaces - Anyone tried one for this purpose?

[TK1]

Hi Derek & others,

Finally a question where I know the answer, and contribute rather than glean information! Apart from building model ships, I fell into the trap of collecting and restoring old woodworking tools. So bit of a junkie now (or junk collector as the wife puts it).


So....the short answer is, everything rusty I get and want to restore, gets a good soaking in citric acid, and it works a treat.

First, I use a brush, rag, etc to remove any dirt, surface rust and grime, then break planes, etc into individual components.

My very unscientific process is to then get a bucket, old cake tin or sink (depending on size and quantity of objects needing treatment), fill with hot water (hot water accelerates the process apparently), and pour in part or all of one of those cardboard containers of citric acid from the cake section in the supermarket. I don't measure the ratios or put anything else in.

It smells pretty bad, so best to do in the shed or outside (having been banned from the house after first attempt in laundry). I leave overnight (too long and it will eat into the metal), then rinse all parts thoroughly under running water whilst rubbing with a brush or fine steel wool. You'll find the rust turns to a sludge, but still adheres a bit to the metal so needs to be wiped off - water also removes all traces of the acid to ensure the reaction stops. Doesn't seem to affect jappaning or paint as long as there isn't rust beneath it.

Dry everything off thoroughly, then go about whatever resoring you plan to do. Parts that were badly rusted and which I won't do anything with for a while, I wipe over with oil or WD40 on a rag to stop any surface rust reforming before I get to do a proper restoration.

OK, that was actually the long answer. In short, it works and I've never been tempted to try electrolysis (especially after reading it can explode if done wrong, in a Wood Review from last year I think). Throuw a couple of packs in the trolley next time you're shopping (and at about $1 each it's cheap) and go for it.

Once we've moved house and the tools are out of boxes I'll post some before and after pics.

Happy to answer any other questions on this if I can. hard to do it wrong though.

All the best,

Darren
"Model Shipwright"

[TK1]

Forgot to mention....it doesn't appear to hurt timber (saw or plane handles) but if they're not varnished/sealed and they are in with a lot of rusty stuff, as the rust leaches into the water they can get stained. Should sand off, but best not to put in wood parts - I tend to support them above water level as best I can.

Hope this helps....

Darren

[silentC]

OK, three things come to mind from all that:

1. Electrolysis cannot harm good metal. You can leave the item in the bath overnight and it will have no ill effects.

2. You are buying a consumable which I gather you throw out afterwards. Electrolysis uses a tablespoon of washing soda every time you decide to make a new batch of electrolyte (I'm still on the same one after a year). Of course it is using electricity, so it's not entirely free.

3. There is a smell associated with citric acid, there is with electrolysis as well, but I haven't been kicked out of the laundry - yet.

As for explosions, electrolysis does produce oxygen and hydrogen, which are potentially explosive. For this to occur, you would need to allow it to build up and then introduce a spark or a flame. I counter this by doing it in a well ventilated area with the windows open and by making sure there is no ignition source near by.

I haven't tried citric acid, so can only go on what you tell me. Derek says that it does not leave the metal grey like electrolysis does. If this is advantageous, then perhaps there may be a good reason to try it.

[derekcohen]

citric acid....does not leave the metal grey like electrolysis does

SilentC, I'm not so sure that this is absolutely correct. I have read a few reports that the Citric Acid process does alter the look. It is not bright metal, as in new metal. But it does appear to have a "peuter" look about it, that is, a matt finish. Darren, I'm sure that you could say a lot more than I about this since I have not attempted the CA route yet. But, from reports, it is not as "dead" looking as the electrolysed (zapped) metal.

Regards from Perth

Derek

[bitingmidge]

I've been thinking of getting one of those Enjo or Sabco microfibre mits for tarnished metal to do the regular cleaning of cast iron surfaces - Anyone tried one for this purpose?

No, but they do wonders getting brake dust off mag wheels.

I used to use some special solvent cleaner gunk, and elbow grease, but with one of those things it just wipes off with water!! I have found a bit of detergent works even easier...I really can't believe that it is THAT much better than my neighbours old Metallica tea shirt, but it is!

So buy one, if it doesn't work, get a set of mag wheels and you won't look back.


Cheers,

P

[maglite]

I do know that an old 44 gallon drum 1/2 filled with water with about a dozen oranges and lemons makes for a great degreaser. Just let it soak for a while.....

To remove rust you could always try a ball of aluminium foil and some coca cola...yep the soft drink.....active ingredient phosphoric acid....works a treat on chromed surfaces....cant see that it wouldnt work on any type of metal.

Amazing stuff that coke......can even be used as a drain cleaner......makes you wonder what it does to your stomach eh
Thats the reason i only drink beer....but i have heard that some brewers use arsenic in minute quantities as a preservative......so it looks like we are all doomed either way.

cheers
Steve

[derekcohen]

Steve

I recall pictures of steel bolts being dissolved in glass jars filled with Coke ...... :eek:

Now if only beer removed rust what a yarn we could spin for our wives!

Regards from Perth

Derek

[simon c]

...active ingredient phosphoric acid....

Hi Steve,

I think you've got some relevant points and some urban myths in here.

Coke will remove tarnish but its mainly the carbonic acid (from the carbon dioxide) that is at work rather than the very low quantities of phosphoric acid. You'd be better off using soda water as it contains as much carbonic acid but doesn't have all the other sugary additives. A lot of these rumours are spread about Coke as it is a famous brand.

And I'm sorry derek but Coke doesn't dissolve steel, you would need very concentrated phosphoric acid to do that.

And compared to the strung stuff you have in your stomach, Coke is fizzy pop.

Simon