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

[thick_mike]

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.

 

[No skills]

will bear that in mind, thanks.

 

[Harbo]

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

Rod

 

[thick_mike]

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.

 

[Phil Pascoe]

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

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

 

[Benchwayze]

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

 

[mickthetree]

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!!

 

[marcros]

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!

 

[Racers]

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

 

[adidat]

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

 

[Eric The Viking]

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.

 

[jimi43]

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

 

[Scouse]

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.

 

[thick_mike]

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.

 

[thick_mike]

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.

 

[No skills]

Interesting, acid base or something else?

 

[SammyQ]

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!!

 

[thick_mike]

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.

 

[thick_mike]

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!!

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).

 

[jimi43]

Fantastic! Our very own chemistry team!

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

Jim