# Corro Dip - If you were wondering.....



## jimi43 (8 Apr 2012)

Over on the HAND TOOLS forum, those interested will have watched the slow restoration of the German Horned Smoother.......yesterday's only bootfair find.

I thought it would be interesting for those readers of the GENERAL FORUM to post the result of a night in warm CORRO DIP...my favourite rust removal chemical.







Quite impressive eh!?

It's not cheap stuff but as can be seen....quite effective!

The key to this stuff is that unlike any other process...the crispness of the mark is retained. All too often you get softened or obliterated marks as a result of over-zealous rubbing on wire brushes, abrasive papers and polishers.

For the historical restoration of old and valuable tools...this has to be one of the best methods which retains the maximum amount of the unaffected metal.

Jim


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## wallace (8 Apr 2012)

Blimey its expensive, over £100 for 5 ltr. How many times can you use the solution, does it depend on how rusty an item is.
Mark


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## jimi43 (8 Apr 2012)

wallace":1udeiixe said:


> Blimey its expensive, over £100 for 5 ltr. How many times can you use the solution, does it depend on how rusty an item is.
> Mark



Hi Mark

That is concentrated.

You only need 1 litre...which dilutes 5:1 to give 6 litres for about £20

It is totally reusable....so I just filter off the rubbish at the bottom each time and put it back in the tub,

It doesn't appear to have lost its effectiveness....and I still have about 1/2 ltr of concentrate left.

It is also totally user friendly...I just dip my hands in it to remove the bits. Much nicer than using concentrated phosphoric acid...more effective by far...and less dangerous.

Jim


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## Eric The Viking (8 Apr 2012)

That is impressive!

And timely too as I have some work to do of that sort, soon. I'm going to try electrolysis too (just rebuilt a battery charger for the porpoise), but Corro dip is on the list for the tricky bits.

Thanks for posting Jimi.

E.


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## 9fingers (8 Apr 2012)

Never tried corro dip but I can thoroughly recommend the electrolytic method Eric, but keep the current down for best results to minimise gassing as the bubbles interfere with the process. Less than an amp unless the object is huge.

Bob


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## DrPhill (8 Apr 2012)

9fingers":3g1iqa24 said:


> Less than an amp unless the object is huge.



It is quite large - it is a porpoise!



Eric The Viking":3g1iqa24 said:


> (just rebuilt a battery charger for the porpoise)



(Sorry Eric  )

Looks like excellent stuff though. Very impressive.


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## Steve Maskery (8 Apr 2012)

Wow! What exactly is in it?
S
Edit - I mean the chemical, not the porpoise....


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## Hitch (8 Apr 2012)

For anyone interested, theres a nice bit about electrolysis here-

http://www.mig-welding.co.uk/forum/show ... php?t=8024


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## Eric The Viking (8 Apr 2012)

DrPhill":r1uv1jt9 said:


> 9fingers":r1uv1jt9 said:
> 
> 
> > Less than an amp unless the object is huge.
> ...



It's fine. 

You weren't to know I'm restoring a Cetaceanary engine. 

I'll get me trunks an' flippers...


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## marcros (8 Apr 2012)

Hitch":2xw0clvo said:


> For anyone interested, theres a nice bit about electrolysis here-
> 
> http://www.mig-welding.co.uk/forum/show ... php?t=8024



Ah, that helps. I tried a setup for the first time yesterday, but used sodium bicarbonate (baking soda) instead of washing soda. May explain why it only worked to a limited extent.


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## Steve Maskery (8 Apr 2012)

I'm not sure that would make much difference. The electrolyte only allows the current to flow, I think it can be just about anything. My chemistry is a tad dated, though, so I may be missing something. But I think that as long as it is more electro-positive, the oxide will move from the cathode to the anode. Or is it the other way round? Nurse! NURSE!
S


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## thick_mike (8 Apr 2012)

A couple of notes on electrolytic rust removal from my experiments:

You just need to put a salt of some sort into solution to allow the current to flow. Bicarb or washing soda will work. Table salt (NaCl) is less preferable as chlorine gas (toxic) can be discharged at the anode.

You're basically electrolysing water so you get hydrogen gas given off at the cathode and oxygen gas given off at the anode (you can check this by holding a match to the bubbles formed, they do the squeaky pop you might remember from chemistry in school). The electrolysis doesn't plate iron onto the surface of the part you are de-rusting (the cathode).

The hydrogen seems to reduce the iron from Fe2O3 to Fe3O4. The Fe3O4 is sometimes called black iron oxide, which is not crumbly like normal rust. So the surface is cleaned and more robust, but it isn't shiny metal.

That is _my_ experience and of course your mileage may vary.

I'd love to know what the active ingredient is in the corro-dip. It would defy the laws of chemistry if it carried on working for ever, so it must lose effectiveness eventually. It certainly brings the shiny though!


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## DTR (15 May 2012)

I'm about to take the plunge (not literally) on this corro dip stuff. My only concern is that it will ruin the logo etch on a saw plate. Fair enough if there is rust beneath the etch, but what if there's not?...


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## jimi43 (15 May 2012)

DTR":3bah36ww said:


> I'm about to take the plunge (not literally) on this corro dip stuff. My only concern is that it will ruin the logo etch on a saw plate. Fair enough if there is rust beneath the etch, but what if there's not?...



My personal view is that it will possibly destroy the colouring of any etch but not necessarily the depression which can be recoloured afterwards.

If I were thinking about doing a saw of potential value...monetary or sentimental...then I would try it on an old S&J first or knackered Disston...

This applies to any unknown..including finishes, polishes etc.

Jim


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## DTR (15 May 2012)

Good suggestion... Thanks Jimi


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## mickthetree (15 May 2012)

Hi Jimi

Sorry if you have already posted this elsewhere but do you have a source for corro dip?


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## adidat (15 May 2012)

here you go dude!

corro dipppppy/ black magic


adidat


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## mickthetree (15 May 2012)

Cheers!!


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## DTR (15 May 2012)

Ordered


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## marcros (15 May 2012)

has anybody found a source other than the manufacturer direct?


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## adidat (15 May 2012)

whats it do to brass?

also a tenner for p+p strikes me as a bit steep

adidat


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## jimi43 (15 May 2012)

adidat":2z3g1hyg said:


> whats it do to brass?
> 
> also a tenner for p+p strikes me as a bit steep
> 
> adidat



It cleans it for a short dip but eats it entirely over a long immersion.

I put one of those Victorian farthings in with the axe to clean it and it virtually disappeared!

Good job I got some spares!

Jim


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## Steve Maskery (15 May 2012)

adidat":1r98hwf8 said:


> whats it do to brass?
> 
> also a tenner for p+p strikes me as a bit steep
> 
> adidat



Why, adidat? They can hardly just stick a stamp on it and pop it into a post-box. It will have to be safely packaged and probably sent by courier. You may even find that they are subsidising the true cost of processing the order. But we are already discussing that on another thread.

FWIW, I am currently considering increasing my P&P rates. I subsidise every one of my overseas customers, and they are the majority. I just about break even on the UK P&P, Some I gain, some I lose, depending on exactly what people buy, but it just about evens out. In contrast, when I send out to America or Australia, it costs me about £17 when I charge £9.99.

The cost of processing an order is not trivial anymore.

S


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## marcros (15 May 2012)

£10 postage on the corrodip may reflect what it costs to pack it, process an order and post it, but it is enough to make me look for either a stockist of that product (it seems that there are none locally), or of something similar. There is obviously profit on the product, which should cover the cost of processing an order from it. I dont believe that the cost of processing internet orders is that significant to the likes of the manufacturers of the product. I am not commenting on Workshop Essentials which is obviously an entirely different type of organisation.

Postage in general is becoming extremely expensive for anything greater than 750g, where the prices rise steeply. That said, there is the potential for good courier contract rates, and they will be making a good few quid on the postage alone of that corrodip. I am not asking that they subsidise it, I am just stating that the subconscious rate at which I question the value is set at below the £8.whatever it was + VAT I was quoted. Likewise, there have been ebay items where I have not bid because the value I put on items is less than what I would have to bid to win and the postage.


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## thick_mike (15 May 2012)

Says it's "Blend of partially neutralised organic salts and natural acids" on the website, so probably doing a similar thing to acetic or citric acid with a few knobs and whistles thrown in.


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## Tony Spear (15 May 2012)

Jim, I've been meaning to post a couple of questions for you, so it's lucky that this thread has come to the surface as it already answers one question i.e. it seems that Liquid Engineering is the only source? Seems odd that, as you'd imagine that the likes of Axy, Rutland, Toolstation etc. would buy it by the vanload, leaving L.E. to concentrate on their Industrial users!

Second question: due to various health problems, I haven't been near my lathe for ages and it's now more than somewhat rusty. I need to de-rust the bed, tailstock, toolrest, the spindle nose and a few minor things. I assume that I can use Corro Dip, but how?
Just dilute it and paint it on? If so what dilution would you suggest?


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## jimi43 (16 May 2012)

Tony Spear":1qy3mqub said:


> Jim, I've been meaning to post a couple of questions for you, so it's lucky that this thread has come to the surface as it already answers one question i.e. it seems that Liquid Engineering is the only source? Seems odd that, as you'd imagine that the likes of Axy, Rutland, Toolstation etc. would buy it by the vanload, leaving L.E. to concentrate on their Industrial users!
> 
> Second question: due to various health problems, I haven't been near my lathe for ages and it's now more than somewhat rusty. I need to de-rust the bed, tailstock, toolrest, the spindle nose and a few minor things. I assume that I can use Corro Dip, but how?
> Just dilute it and paint it on? If so what dilution would you suggest?



The only place I have seen it is from LE...so I guess that must be the only source. Since I bought my litre at a bootfair for 50p...I haven't really looked elsewhere. 8) I am a bit p*d off that I didn't buy all the stock the guy had...knowing what I know now...but at the time I thought it was just one of those hyped up "as seen on TV" type products.....until I tried it one day.

The only "non-dip" method I used was to heat it right up and paint it on my steel scaffolding (mostly the feet) and just leave it there. It dried on leaving a kind of black skin...no rust. I wire brushed a bit which left quite clean metal but gave up after a while as it seemed pointless to remove the black finish..

Since then the feet have not rusted at all and all the bolts work fine.

For the lathe...I would put on a pair of latex gloves and wipe it on....then later polish it off with a copper brush....

If I get time this week I will do a few tests...but I don't like using too much on brush on because it can't be reclaimed. 

Will let you know how the tests go.

Jimi


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## Benchwayze (16 May 2012)

Hey Jimi, 

Nothing wrong with S&Js.... 8) 

I have a nice pair (Rip and Cross) I wouldn't part with. (Plus they give me a good aerobic work-out! Well, I guess any hand-saw will do that, but you know what I mean!) :lol:


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## Eric The Viking (16 May 2012)

jimi43":2rplcx6s said:


> For the lathe...I would put on a pair of latex gloves and wipe it on....then later polish it off with a copper brush...



Jimi,

Do you think the old Nitromors tricks might work: paint it on as you suggest and cover with damp newspaper + clingfilm, to limit evaporation?

As you know, I've got a few sash cramps to do...

E.


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## jimi43 (16 May 2012)

Benchwayze":c0ch6h7p said:


> Hey Jimi,
> 
> Nothing wrong with S&Js.... 8)
> 
> I have a nice pair (Rip and Cross) I wouldn't part with. (Plus they give me a good aerobic work-out! Well, I guess any hand-saw will do that, but you know what I mean!) :lol:



Hey John...I know...I just don't like them. I think that it might be down to their domination of the market in later years and the loss of so many small independent makers....and my memories of that horrible orange plastic handle!

Eric...it's a difficult one mate...let me try on something and get back to you.

Jim


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## thick_mike (16 May 2012)

Eric The Viking":1t4o46sf said:


> jimi43":1t4o46sf said:
> 
> 
> > For the lathe...I would put on a pair of latex gloves and wipe it on....then later polish it off with a copper brush...
> ...



The active component in Nitromors was a volatile solvent (hence the recommendation to cover to prevent evaporation). The active components of Coro-dip don't look to be volatile, so should be less necessary, but I guess it will stop it drying out.


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## Benchwayze (16 May 2012)

Ah well Jimi.,

Mine are circa 1960/70. Wooden handles. Kept well too. 
I did offer them for sale a few months ago, but no one was interested. So I sharpened 'em and put 'em in me tea-chest tool-box! !


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## jimi43 (16 May 2012)

Of course John...and the old ones are great...I'm just a bit of a Sorby man meself! :wink: 

On the subject of rust removal from items which cannot be dipped...I have contacted Liquid Engineering and should hopefully have an answer on that one too soon.

Cheers

Jim


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## Tony Spear (16 May 2012)

jimi43":1qdb1fcf said:


> On the subject of rust removal from items which cannot be dipped...I have contacted Liquid Engineering and should hopefully have an answer on that one too soon.
> 
> Cheers
> 
> Jim



Thanks Jim, looking forward to what they have to say.

I suppose I could have asked them myself, but I thought I'd ask somebody who's used it in a woodworking situation first.


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## foxhunter (16 May 2012)

Can Corro Dip be bought retail. The web site quotes £8.50 carriage for the smallest size.


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## dickm (16 May 2012)

Being an inveterate cheapskate, and being near my 70th birthday, spending £35 on something that will probably not be used that often feels wrong  . Wonder if there is any mileage in woodworking clubs buying a 5 litre can and splitting it for sale to members?


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## soulboy (16 May 2012)

dickm":2ccbtgyc said:


> Wonder if there is any mileage in woodworking clubs buying a 5 litre can and splitting it for sale to members?


 Hi Dick, I suggested something like that some months ago but no replies/comments, I guess re-distribution might be complicated?
chris


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## marcros (16 May 2012)

trouble is, unless people are local to each other, you will end up wasting any saving having to post it on.


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## No skills (16 May 2012)

I've got an old wooden plane iron and some pretty nasty acid at work, if I get time this week I will try and see if it works as a clean up medium.


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## Benchwayze (16 May 2012)

I hear that Malt Vinegar works well, but takes a little longer. It's certainly cheap and available enough.

I don't know if any specific brand works better than another, :mrgreen: but I like 'Asda's Smart-Price' on my chips. Sarson's is too acidic for me! That might be a clue I suppose! 8) 

I haven't tried vinegar for rust removal, because up to yet I haven't had anything rusty enough to need any treatment other than elbow grease, abrasive or a wire-brush.


HTH


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## thick_mike (16 May 2012)

No skills":347gyc1t said:


> I've got an old wooden plane iron and some pretty nasty acid at work, if I get time this week I will try and see if it works as a clean up medium.



Best to use weak acids (organic acids like acetic or citric) rather than strong acids (hydrochloric or sulphuric etc). Weak acids will eat your metal slower than the strong acids. Had some fun dropping old pennies into conc. nitric the other day at school...ended up with lots of brown smoke and no pennies.


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## No skills (16 May 2012)

will bear that in mind, thanks.


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## Harbo (16 May 2012)

Milk Stone Remover from Agricultural Suppliers is a cheap way to buy Phosphoric Acid.

Rod


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## thick_mike (16 May 2012)

Been doing a bit of reading around this subject (having purchased plenty of rusty tools recently), looks like some rust removers contain chelating agents. These are chemicals that bind to the iron in the rust and form a stable molecule. Will try to knock something up in the lab tomorrow with EDTA.

Must say though that this does not imply that this is anything to do with corro dip. They obviously have their own proprietry chemistry. Sounds like it's an excellent product. I'm just interested in a home brew solution as a chemist and possessor of rusty tools.


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## Phil Pascoe (16 May 2012)

soulboy":2ybo2e44 said:


> dickm":2ybo2e44 said:
> 
> 
> > Wonder if there is any mileage in woodworking clubs buying a 5 litre can and splitting it for sale to members?
> ...


 Possibly more complicated by not knowing people's locations :wink:


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## Benchwayze (17 May 2012)

To 'keep it in house', I think we should let Mike find something that works, then buy it from him!


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## mickthetree (17 May 2012)

I've tried citric acid with some success, not like Jimis corro dip though!!

I got it originally for cleaning baby bottles and sterilisers. I got a quizzing from the pharmacist in boots when I wanted to buy more than one box (they are only tiny). Not sure what she thought I was going to do with it!!


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## marcros (17 May 2012)

mickthetree":3r3clac5 said:


> I've tried citric acid with some success, not like Jimis corro dip though!!
> 
> I got it originally for cleaning baby bottles and sterilisers. I got a quizzing from the pharmacist in boots when I wanted to buy more than one box (they are only tiny). Not sure what she thought I was going to do with it!!



They wouldnt sell it to my wife for its original purpose- sent her off with a sterilising formula instead!


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## Racers (17 May 2012)

mickthetree":10m3x8py said:


> I've tried citric acid with some success, not like Jimis corro dip though!!
> 
> I got it originally for cleaning baby bottles and sterilisers. I got a quizzing from the pharmacist in boots when I wanted to buy more than one box (they are only tiny). Not sure what she thought I was going to do with it!!



Its used by drug users :shock: 

Pete


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## adidat (17 May 2012)

a package arrived today

got some plane blades and lever caps "pickling" some of these were pretty poor looking, how long for the brass ws caps?

results to come

adidat


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## Eric The Viking (17 May 2012)

I wouldn't pickle brass!

It's an amalgam of copper and zinc, and it readily suffers from de-zincification, which is one way for radiator valves to fail (they go cheese like). 

If you clean it chemically, at best it will go copper-coloured as the zinc leaches out. At worst you will destroy its structural integrity. If it goes coppery, you can polish it back to brass colour usually, but anything that's very reactive will do damage.

I'd use something like Dura-Glit wadding (now "Brasso" brand), which is pretty gentle, or a weak acid, perhaps brown sauce (seriously!) if it's bad, bearing in mind you're taking metal away. Proper Brasso liquid works pretty well, but it contains more abrasive than the wadding (I think the active chemical is the same). I think the Brasso lot also now own Goddard's silver wadding - that ought to be even more gentle. You can also get good results with mild abrasives such as Jif (Zif/Cif/whatever) and Jewellers' Rouge, which, in theory, don't have the acidic ingredient. 

Bear in mind too that it tarnishes readily after you've cleaned it. In the past I've successfully lacquered brass with cellulose car varnish, by warming the piece in the oven first (around 75, <100deg C), spraying it, then returning it to the oven. There are undoubtedly better ways, but I don't have a spray booth!

Hope that helps.

E.


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## jimi43 (17 May 2012)

Hi Chris

Eric is right...don't put the brass lever cap in it. It will dissolve it far quicker than you can imagine.

Brass is easy to clean with Autosol or other metal polishes. I would use MAAS but that is what I have found to be the best...any will do really.

Looking forward to the results

Cheers

Jimi


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## Scouse (17 May 2012)

adidat":i7q23dzj said:


> how long for the brass ws lever caps



WS lever caps come up like new with literally only 2 or 3 minutes with Brasso, from this







to this






Although, as with everything, I just had Brasso handy, other polish will be as good if not better.

El.


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## thick_mike (17 May 2012)

Had a bit of a play in the lab today and things didn't turn out too bad:






Not a before and after, but the one on the right was a bit worse than the one on the left before a couple of hours in...






Haven't had a chance to tweak the formulation, just whacked it together. Have just put these in to soak:









Will report back later, Mike.


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## thick_mike (17 May 2012)

Well, that seemed to go quite well.

Here's the plane iron:






And here's the rule from the square:






Took about an hour in the solution and then two minutes with a brush.

Will do some more trials tomorrow.


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## No skills (17 May 2012)

Interesting, acid base or something else?


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## SammyQ (17 May 2012)

Mike, I am now watching this thread with very active interest. Your side reference to EDTA took me back 35 years and the TDI* lab where I used to work; Lord! How we blithely threw every shade of organic solvent around....you just couldn't get away with it now! 

Moreover, as someone "...just interested in a home brew solution and a possessor of rusty tools", but also but the father of a soon-to-graduate chemist and with a healthy school lab suite to play in, I am hoping to shamelessly plagerise your findings and make 'homebrew' to excavate my lovely old Bedrock and sundry other goodies from beneath their mantle of Iron Oxide. PLEASE publish - three sets of university fees at the same time leave Corrosplash at the outermost budgetary margins and about as obtainable as an honest politician....

Sam

* Toluene Di-iso Cyanide/Cyanate (expanding wall insulation basic component?). It has a nasty habit of exploding vertically out of the inspection tube you are bending over, when accidentally mixed with EDTA amongst other things..... DAMHIKT!!


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## thick_mike (17 May 2012)

No skills":2bz701t7 said:


> Interesting, acid base or something else?



A bit of this and that really. EDTA which is a chelating agent ( a bit like a chemical crab!), acetic acid, sodium citrate, citric acid and some ammonium hydroxide to bring the pH up to 4 Ish so that it's not too corrosive. Nothing hazardous in there. Haven't had time to do any optimisation, so I'm not sure if it can be improved. Haven't used the commercial products so not sure how this compares, but it seems to work pretty well anyway.


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## thick_mike (17 May 2012)

SammyQ":3ckwqac8 said:


> Mike, I am now watching this thread with very active interest. Your side reference to EDTA took me back 35 years and the TDI* lab where I used to work; Lord! How we blithely threw every shade of organic solvent around....you just couldn't get away with it now!
> 
> Moreover, as someone "...just interested in a home brew solution and a possessor of rusty tools", but also but the father of a soon-to-graduate chemist and with a healthy school lab suite to play in, I am hoping to shamelessly plagerise your findings and make 'homebrew' to excavate my lovely old Bedrock and sundry other goodies from beneath their mantle of Iron Oxide. PLEASE publish - three sets of university fees at the same time leave Corrosplash at the outermost budgetary margins and about as obtainable as an honest politician....
> 
> ...



Used to use TDI and MDI when I used to formulate 2K PU adhesives (still love the smell of ethyl acetate). Nasty itchy things.

Can drop you a pm with the recipe so far. Would rather not post it up here as I have no idea if I'm treading on anyone's patent (and can't be bothered to find out really).


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## jimi43 (18 May 2012)

Fantastic! Our very own chemistry team!

Puts a whole new meaning to "would sir like something for the weekend"!!! :mrgreen: 

Jim


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## SammyQ (18 May 2012)

Mike? Apologies, my bad; you are absolutely right about patents. As an ex professional photographer (previous life) and being aware of copyright issues there, I should have reined in my enthusiasm ( = financial desperation). PM sent. Sam


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## SammyQ (18 May 2012)

Jimi? Good thought...but...may I remind you that 'certain elements' of Norn Iron ("Northern Ireland") society played with extravangant chemistry for 30-odd years and a new venture of us woodies making 'homebrew' might draw unwanted attention from the rozzers?   

Having said that, I trained under a chemist who used to make his own aftershave and eau de toilette...in his later years, it was more like eeewwww! de toilet...

Sam


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## thick_mike (18 May 2012)

SammyQ":3kyxcggo said:


> Jimi? Good thought...but...may I remind you that 'certain elements' of Norn Iron ("Northern Ireland") society played with extravangant chemistry for 30-odd years and a new venture of us woodies making 'homebrew' might draw unwanted attention from the rozzers?
> 
> Having said that, I trained under a chemist who used to make his own aftershave and eau de toilette...in his later years, it was more like eeewwww! de toilet...
> 
> Sam



I make my own hair conditioner...50 p a litre!

Because I'm worth it.


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## mickthetree (18 May 2012)

From corro dip to conditioner. Don't get them mixed up now guys!! ;-)


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## thick_mike (18 May 2012)

mickthetree":32r7oxcq said:


> From corro dip to conditioner. Don't get them mixed up now guys!! ;-)



I need to be careful, being a ginger.


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## jimi43 (18 May 2012)

mickthetree":33kjr53l said:


> From corro dip to conditioner. Don't get them mixed up now guys!! ;-)



And if you are using it on planes...take care it's only on the bed and shoulders..... :mrgreen: 

Ok..ok..coat on...out the door...down the path...miles away by now!  

Jim


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## thick_mike (18 May 2012)

Been playing today, but been a bit lax in taking before/after pics. Things I have noticed...

1) whatever you dip becomes warm (mix could do with diluting?)
2) copper is removed from the brass brush if you rub it wet. Copper is then deposited on the tool giving it a slightly yellow tinge.
3) flash rusting doesn't seem to be a problem as it can be with electrolysis.
4) it really emphasises any laminations in plane irons
5) it makes your microwave smell like vinegar
6) my skin hasn't fallen off
7) i tried a couple of rusty files to see what happens. Both of the ones I have tried so far are really sharp. I guess they were sharp before rusting, but still, this was surprising.

I thought it was time for a challenge:







And the winner is....chemistry!


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## mickthetree (18 May 2012)

thick_mike":1alxa56w said:


> Been playing today, but been a bit lax in taking before/after pics. Things I have noticed...
> 
> 1) whatever you dip becomes warm
> 
> 5) it makes your microwave smell like vinegar



1 & 5 linked perhaps :wink: 

I've got a box full of files that are a tad rusty. When did you say you were going to market with this product?  

tut tut Jimi :roll:


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## 9fingers (18 May 2012)

There was (is?) a chemical process for regenerating engineers files.
Those older readers who might remember Ken Whiston of "seen my Cat?" fame would recall seeing an assortment of these files offered for sale. I did have some once and they certainly seemed quite sharp and much more suited to my pocket.

Bob

From cat 124 September 1989 
item 5008W
Surplus Workshop Assortment of Regenerated Files. all sorts 6" to 12", 10 for £8.78


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## SammyQ (18 May 2012)

Bob? Is that file restoration not simply electrolysis of the files? 

I've done a bit of quick research and my indications are that Corrodip may use a chelating agent that is NOT EDTA, but 'an organic/sulphur' compound....so tramping on patent toes seems to have receded as an issue.

I'm a scientist and have 3 chemists working alongside me. I'm going to go away and mull this all over to see if I can add 2d (pre-decimal currency!) to back up Mick's elegant start to all this. It sure as Hades is nice to find an affordable way to maintain expensive and utterly necessary tooling in an aopropriate state.

Sam


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## dickm (18 May 2012)

9fingers":1l6o1zrh said:


> There was (is?) a chemical process for regenerating engineers files.
> Those older readers who might remember Ken Whiston of "seen my Cat?" fame would recall seeing an assortment of these files offered for sale. I did have some once and they certainly seemed quite sharp and much more suited to my pocket.
> From cat 124 September 1989
> item 5008W
> Surplus Workshop Assortment of Regenerated Files. all sorts 6" to 12", 10 for £8.78


Oh heck, that takes me back. But to the late 1960s.

Don't anglers use "chemically sharpened" hooks? Presumably the same process.


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## Tony Spear (18 May 2012)

dickm":3a14qzbz said:


> Don't anglers use "chemically sharpened" hooks? Presumably the same process.



It's always puzzled me how they do that! :? 

BTW. reatents. If Mick thinks he may have a marketable product, the obvious answer in American marketing jargon is "run it up the flagpole and see if anybody salutes!

i.e. Put it on the market and you'll soon find out if anybody thinks their Patent is being infringed! Plus anybody that feels that way would have to reveal their own composition if it ever went to Court! That of course, provided there aren't any restrictions on the various ingredients, could lead to hundreds of people making their own! :mrgreen:


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## DTR (18 May 2012)

thick_mike":q4bynljr said:


> 7) i tried a couple of rusty files to see what happens. Both of the ones I have tried so far are really sharp. I guess they were sharp before rusting, but still, this was surprising.



I read somewhere that one way to sharpen a file is to leave it outside to rust for a short while. When the rust is removed what is left is the original (sharp) profile. Or something to that effect. I must try and find where I read it...

*edit:* found it. Taken from lathes.co.uk:

_Restoring files - blunt files can often be resharpened by allowing them to rust in the garden for a few weeks. Due to the erosion of the teeth, the correct form is, to an extent, restored._


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## No skills (18 May 2012)

(Now going way off track and on safari somewhere..  )


Not heard the rust your file to sharpen before, might look into that. I think I have read in my blacksmith book that leaving old files in acid solution will sharpen them to some degree - partly from dissolving anything thats clogging the teeth (anything that will dissolve that is) and partly from the acid eating away at the narrowest edge of the teeth making them finer.
Thats not a good description at all but I think you should get the drift.


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## dickm (19 May 2012)

If anyone is thinking of patenting (anything), then it's apparently important not to reveal any details in any way before applying for patent. Got caught out years ago when some work we were doing could have resulted in a patent, but it got some publicity in local press which was enough to invalidate any application.

Of course, if our resident chemists want to do experiments and publish details for the common good, then let's encourage them.


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## Giff (19 May 2012)

Is Corro-Dip similar to this one. http://shieldtechnology.biz/restore%20photogallery.html
Axminster sell it in small and large bottles. There is a liquid and a gel, they are re-useable and bio-degradable.. Giff


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## jimi43 (19 May 2012)

Giff":2zigmvdy said:


> Is Corro-Dip similar to this one. http://shieldtechnology.biz/restore%20photogallery.html
> Axminster sell it in small and large bottles. There is a liquid and a gel, they are re-useable and bio-degradable.. Giff



Probably is the same stuff...by the look of it. 

About the same price too if you divide 20:1 to 6:1 and then multiply by 4 to get a litre.

I haven't tested this competitor so I don't really know but they sell a degreaser at the same price which would indicate the tool might benefit from degreasing.

Would be interesting if someone bought a bottle and tested it....I won't need to buy any more for some considerable time as I have loads left...and as I said...that is a couple of years old even though I do restoration of tools every week. :wink: 

Jim


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## Setch (20 May 2012)

I used the shield tech' Restore on a chisel which I finished tarting up today - I'll post some before and after pics, but it seems to work very much like you've described the corro dip.


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## AndyT (20 May 2012)

If Alf was still posting on here, she would doubtless have chipped in with some useful and thoughtful contributions by now. As she seems not to be, I hope she won't mind if I lead the way to her blog post from March 2011 where she did a direct comparison between the Shield rust removers and citric acid.


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## Harbo (20 May 2012)

Yes a pity Alf is no longer posting - a great loss?
I use Deosan "Dilac Plus" Milkstone Remover which is a cheap way to buy Phosphoric Acid. (info gleaned from an Vintage Car Forum).
Comes a in a 5L container and is diluted with water. Works well but the finished black/grey coating needs removing with wire brushes etc if a sparkly finish is required?

Rod


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## Tony Spear (20 May 2012)

It's beginning to look as though we need to have a whip-round to buy Jim samples of all the main contenders and try to persuade him to do a comparitive test for us! 8) 

Having said that, I don't know what we would need to use as an incentive for Jim! :mrgreen:


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## Tony Spear (20 May 2012)

P.S. I notice that Axy do a Liberon rust remover, which they claim is also an inhibitor! :?


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## jimi43 (20 May 2012)

I would be happy to do that Tony...price would be..you guys send me your tools to use as test items and I keep them! :mrgreen: 

Corro Dipped tools seem to have a rather attractive greyish patination after treatment which seems to be resistant to rusting again. It certainly doesn't flash rust like electrolysis and the erosion of good steel is minimal as you get which I found wasn't the case with phosphoric acid.

Jim


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## thick_mike (20 May 2012)

I have done some work with phosphoric acid, electrolysis and the chelating rust removal. Although my results aren't Quantitative, I have made the following observations:

Electrolysis - easy to set up with minimal cost (old phone charger, two crocodile clips, tin can, spoon of bicarb.). Rust removal is good, leaves behind a black iron oxide coating which is prone to flash rusting if not coated immediately with oil. Needs plenty of polishing to restore a shiny surface if that's what you want.

Phosphoric acid - quick and effective, but needs to be watched as the acid doesn't distinguish much between rust and steel. This may be because I had access to conc. phosphoric acid. Leaves behind a grey coating which is robust and doesn't rust, but needs plenty of polishing to restore a shiny surface. Obviously some hazards associated with corrosive acids.

Chelating approach - fiddly or expensive, quick, good rust removal without etching the steel. Requires minimal polishing to leave a shiny surface. Not prone to flash rusting. Not particularly corrosive, but makes your microwave smell a bit temporarily.

Left a file in the chelating mix over the weekend to see what happens. The rust was removed, but there doesn't seem to have been any observable etching of the good steel underneath.


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## jimi43 (20 May 2012)

My observations exactly Mike. Which is why I don't bother with any other system now. By heating the mixture...all but the worst rust disappears after only about 1 or 2 hours.

Jim


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## The Bear (20 May 2012)

Does it get rid of the worst rust if left longer?

Mark


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## thick_mike (20 May 2012)

The Bear":clkk9wp0 said:


> Does it get rid of the worst rust if left longer?
> 
> Mark


I've used it on some pretty crappy examples and it's removed the lot. It's not a miracle though, it won't replace steel that has rusted away. Your really old tools may be pitted to hell under the rust and be unusable.


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## Tony Spear (21 May 2012)

jimi43":3cgcuoaj said:


> I would be happy to do that Tony...price would be..you guys send me your tools to use as test items and I keep them! :mrgreen:
> Jim



Are you sure you want a bloody great lump of cast iron? :roll: 

Probably cost more to get it to you than it's worth! :shock:


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## foxhunter (22 May 2012)

I have just been in contact with Liquid Engineering and find that Corro-Dip is out of stock and will not be available for some weeks. A container apparently left Australia 9 weeks ago and was last heard of in Singapore!

They are encouraged by the reports in this thread and may consider making it available through various retail outlets.


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## DTR (22 May 2012)

foxhunter":21aavdjq said:


> I have just been in contact with Liquid Engineering and find that Corro-Dip is out of stock and will not be available for some weeks.



The Jimi Effect?


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## AndyT (22 May 2012)

I fear the container may be about to wash up on the Kent coast in the early morning - please all form an orderly queue!! :lol:


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## Setch (22 May 2012)

The chisel I treated had some relatively deep pitting in places, and i found the dip turned the rust in the pits black, but only at the surface - deep pits benefited from having the black scraped away to reveal more rust before going back in the jar.


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## thick_mike (22 May 2012)

Setch":2h6nlt3n said:


> The chisel I treated had some relatively deep pitting in places, and i found the dip turned the rust in the pits black, but only at the surface - deep pits benefited from having the black scraped away to reveal more rust before going back in the jar.



I've found the same. I soak the tool for about an hour, then give it a gentle brush with a Brass brush before soaking again for another hour.

When I take them out, give them another brush, rinse in water, then a squirt of WD40 or baby oil.

It's quite addictive. I'm looking in the back of all my cupboards, hoping to find something that's gone rusty!


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## thick_mike (22 May 2012)

I've never really had any good files, just picked them up from Aldi when they were on offer. I've also got a whole load of rusty files that I've acquired at the bottom of old toolboxes, so I thought what the hell...







Now I've got a set of pretty cool old files (Thomas Turton, Nicholson, Hale Bros, Firth) that are sharp and ready for action. Just need to get a couple of them in some solvent to get rid of the paint.

This stuff just keeps going, so far 1.5 litres has done 10 chisels, 15 files, 4 plane irons, 5 back saws, 2 sets of plough plane irons and 10 auger bits; need a new brass brush though.


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