reverse electroplating

[richardHaw]

Hello, everyone!

as the title says, I want to reverse electroplate some camera parts to strip the chrome and nickel back to the brass substrate.
back home, I use hydrochloric acid and sulfuric acid. these chemicals arent easy to buy here in Japan and you will require some kind of license or at least fill up a form. they are also not easily available so i cannot just walk into a shop and ask for some even if I have a license or fill up a form. these restrictions are common sense since these acids are popular among people who wish to end their lives early.

so here's the question: what is a good alternative to these?

I have citric acid which i use all the time to clean the corrosion from the slow governors of the cameras that i repair but this thing is only good from stripping the chrome top layer btu the yellowish nickel is still intact.

apologies if I cannot reply quick as I am busy these days in my new studio 

[Hugh_3170]

Richard, I don't know where "home" was for you, but here in Australia I have purchased both HCl and H₂SO₄ at hardware and paint stores for stripping paint and preparing concrete floors for the application of epoxy paints.  I don't hnow if there are similar such stores that cater for that sort of thing in Japan.  Also industrial suppliers may be easier to deal with than chemical supply companies who might try and sell you high grade versions of the chemicals which I doubt are needed in this application.

[richardHaw]

Richard, I don't know where "home" was for you, but here in Australia I have purchased both HCl and H₂SO₄ at hardware and paint stores for stripping paint and preparing concrete floors for the application of epoxy paints.  I don't hnow if there are similar such stores that cater for that sort of thing in Japan.  Also industrial suppliers may be easier to deal with than chemical supply companies who might try and sell you high grade versions of the chemicals which I doubt are needed in this application.

thanks! the only supplier I know is monotaro.com  it can be tricky buying from them

[Fanie]

What an interesting dilemma, I guess living in the third world like me has some advantages regarding a complete lack of nanny state supervision 😊

[Hugh_3170]

Yes Fanie, I know what you mean.  Whilst you can get stuff here (in Oz), you do need to seek out alternative suppliers or look for places that sell stuff under different descriptions.  Not everyone even knows what these alternative descriptions are.  It gets most frustrating - all because a few turkeys wish to blow themselves and the rest of us up with them!  Aargh!

What an interesting dilemma, I guess living in the third world like me has some advantages regarding a complete lack of nanny state supervision 😊

[Matthew Currie]

Car batteries use sulfuric acid.  Is it possible you can get it from an auto parts supplier, or maybe just find an old battery somewhere?

Here in the states, you can get muriatic acid from home suppliers and the like, to remove excess tile grout.  Is it possible you can do an end run around the restrictions there? Muriatic is basically impure industrial grade hydrochloric.

I've read you can do pretty well with reverse electrolysis and phosphoric acid, but I don't know if phosphoric acid is strong enough to do it just with a bath.  I have some and will try it, but suspect it's not much better than citric.

[Jacques Pochoy]

I had in memory (from motorcycles) that you could do it also with acetone https://ourpastimes.com/remove-chrome-plating-brass-6706689.html ! Seems less problematic for an individual then getting the over mentioned  acids (that can get into very different troublesome products nowadays) !!!

[arthurking83]

What about hydrofluoric acid?
I'm in Australia too, and can easily buy concentrated HCl at the local hardware stores in bulk bottles. We use it mainly for cleaning concrete, but I also use it as my all purpose floor/bathroom cleaner diluted massively.
Normal bathroom cleaner is fairly inexpensive anyhow, but diluting the concrete HCl makes it peanuts .. and it lasts years!

Anyhow, can you source HF over there, or all all acids hard to purchase.
HF is commonly used as an etchant, ie. to etch into glass in a similar manner to writing. It's a very powerful dissolvant.
Mum used to use it to do etching.
Maybe do a search for glass etching solution or something.

Note with all acids you need face protection, but in my experience, this one needs a bit more again!

[David H. Hartman]

Muriatic acid is a specific dilution of hydrochloric acid (I forget) and is also used to lower pH in swimming pools.

[Matthew Currie]

I threw a piece of a black anodized lens into phosphoric acid for the day and it did pretty well.  I just found a little chrome plated piece of a long gone camera and threw it in for the night.  Will check tomorrow.  This is "Phosphoric Prep and Etch" from Home Depot, dilution  not specified.  Not super concentrated, won't hurt you if a bit gets spilled, but it does do some work.  We use it to dissolve lime buildup in bathroom fixtures. 

It's possible that some fairly powerful acids can still be found as boat bottom cleaners. 

[Hugh_3170]

Be very careful if you use Hydrofluoric Acid (HF) - this stuff is dangerous and Fluorine gas is particularly tough on lungs.

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Cocoa Cola has some phosphoric acid in it to add tangyiness to its taste - so coke may be a source of weak acid for this project.

[beryllium10]

As hydrofluoric acid has been mentioned, this is another cautionary reply to emphasise what Hugh said.  Hydrofluoric acid should be hard to obtain.  Better not to even think about using it.  This acid is used by geochemists to dissolve rocks and minerals, and cannot be stored in glass bottles.  Contact with few square centimeters of skin, untreated, can be fatal.  It shouldn't ever be used outside a fume hood, nor without proper protective clothing or calcium gluconate gel available for treatment in case of skin exposure.  Additional morbid details are here:  http://calgonate.com/files/news1116438029.pdf

[JJChan]

As hydrofluoric acid has been mentioned, this is another cautionary reply to emphasise what Hugh said.  Hydrofluoric acid should be hard to obtain.  Better not to even think about using it.  This acid is used by geochemists to dissolve rocks and minerals, and cannot be stored in glass bottles.  Contact with few square centimeters of skin, untreated, can be fatal.  It shouldn't ever be used outside a fume hood, nor without proper protective clothing or calcium gluconate gel available for treatment in case of skin exposure.  Additional morbid details are here:  http://calgonate.com/files/news1116438029.pdf

+1
I recall nasty death and also evacuation of emergency department of patient who had a major spill whilst trying to clean concrete. Hydrofluoric acid consumes all Calcium - strips from epidermal tissue so instant necrosis, strips Ca from blood - arrhythmias, muscle spasms before painful necrosis etc. V v nasty.

Tokyu Hands had all sorts of amazing equipment and chemicals? I've never seen Dept stores with beakers and glass measuring cylinders. They did have some chemicals of some kind in a section on ?2nd floor Shinjuku
Else Coca-cola may help http://www.starshipmodeler.com/tech/mp_cola.htm

Good luck
JJ

[Erik Lund]

....
Else Coca-cola may help http://www.starshipmodeler.com/tech/mp_cola.htm

Good luck
JJ

Wow, quite impressive I must say!

[Matthew Currie]

A night in phosphoric acid did nothing at all to the chrome except to clean it nicely. I've heard of it as a medium for actual reverse electrolysis, but as a simple chrome-eating acid it's a no-go.