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Author Topic: Swapped Electrodes at Copper Plating  (Read 1443 times)

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Anolym

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Swapped Electrodes at Copper Plating
« on: June 27, 2018, 07:25:21 AM »

Hello,
I'm new to this board so pleas be gentle to me ^^

About a week ago I tried to copper plate a wrech which I had found in my toolbox. I used a Coppersulfate Solution, a copper wire as *Anode* and a 6V / 1,5 A DS Power Supply. I was so confused this day that I swapped the electrodes and havent realised that this Wrench was Chrom plated. So I ended up having my Wrench as an anode. After a few seconds something has formed which looked like a dark green liquid. I stopped this whole process and tooked the wrench out. I looked at the wrench and saw a yellowish drop of this solution. The first thing I googled was "Green Chromium Compound". But the drop at the wrench confused me. I could have been wrong because I was quit in panic. So I ended up tossing the solution all over me, my desk, clothes and floor. Could it easily be Chromate which formed? I read about "chrome stripping" online where people used a NaOh solution which is said to produce hexavalent chromium. In another post I found someon who said "HCL = Trivalent, NaOh = Hexavalent". So the oxidation state affected by the pH level?
And finally: Should I worry or would it be ok to take a shower and clean everything with windex? It realy wasnt a lot. I can post a picture of the wrench an the affected area. Im just a little bit paranoid. Wont like to get greeted with cancer due to a silly mistake.

I am happy if someone could help me. Tried in different german forums but nobody had a clue.
Sorry for my bad writing. Im from germany so english is just my second language ^^

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Borek

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Re: Swapped Electrodes at Copper Plating
« Reply #1 on: June 27, 2018, 08:45:01 AM »

I wouldn't worry too much about a single exposure, especially if you washed your skin.
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Anolym

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Re: Swapped Electrodes at Copper Plating
« Reply #2 on: June 27, 2018, 09:25:30 AM »

Yeah I did. Just worried about the left over hex chromium (if anything was created). I Just cleaned everything up with windex and a bucket of soapy water. Today I bought 5 Liters of Ethanol at a local Hardware Store, mixed with a little bit of Water and sprayed the surfaces. Ethanol gets Oxidized to Ethanal and Acetic acid. Ethanal is quiet nasty but I'm not worried about it because (a My windows are 24/7 open ^^ an (b not much is created. I calculated a worst case Chromium amount of about 700 mg. Just calculated the volume of chromium which could have been stripped and multiplied it by the density of Cr. I dont know how much CrO3 you can get out of 700 mg Cr but I bet it isnt much more. So yeah. The Median lethal dose of hexavalent Chromium is 50 - 100 mg / kG. Lets say it is 100 mg/kg you will need to eat 7 grams of chromate (70kg body weight) to have a 50:50 chance to die, right? Thanks for your reply. I appreciate that!
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Enthalpy

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Re: Swapped Electrodes at Copper Plating
« Reply #3 on: June 27, 2018, 09:58:31 PM »

Hexavalent chromium was used by thousands of people for decades before health administrations noticed its toxicity, so it's not very toxic.

And if you stopped the <1.5A current after few seconds, you are extremely far from having etched 700mg.
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Anolym

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Re: Swapped Electrodes at Copper Plating
« Reply #4 on: June 29, 2018, 04:20:14 AM »

Thank you Enthalpy for your reply.

Yeah it doesn't have a acute toxicity but it can damadge the DNA of the Body and can cause mutations. Just reading in the Internet about Chromate makes you paranoid ^^

I calculated the strippable Chromium by this calculation: 15mm (width) * 40mm (height) * 0.01 mm (estimated thickness of the Chromium Layer. Less than Tin Foil which was stripped) This will give me a total volume of 6 mm³ - which is 0,006 cm³.

0,006 cm³ * 7.19 g (density of Chromium) will give me 0,04314 g - 43,14 mg.

To get the total amount of Cr6+: 43,14 mg * 2.66 (factor between Chrome and CrO3) = 114,75 mg

So with my estimated calculation I could have ended up with 115 mg of CrO3. Only if the layer were stripped to 10 µm.

Does anyone know if my calculation could be halfway adequate?

At the Attachment you can find a picture of the stripped area. It isn't that much and it seemed that it were just stripped in this area. The other side and the bottom looked completely normal.
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pcm81

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Re: Swapped Electrodes at Copper Plating
« Reply #5 on: June 29, 2018, 01:40:17 PM »

I have done some chrome electo plating in my garage. The thing about chrome and its advertised toxicity is that chrome plating was the first heavily regulated by EPA industry. There were plenty of choming shops, lots of people using very bad personal protection equipment and many of them developed cancer after many years of exposure.

Usually a chrome plating solution has 33 ounces if chromic acid flake per gallon. Bottom line is: the quantity of chrome you had in that bath is so little that you do not need to worry about it.
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chenbeier

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Re: Swapped Electrodes at Copper Plating
« Reply #6 on: July 01, 2018, 12:47:10 AM »

@ Anolym: You aked this question already in the third forum. I think you got enough answers already In total the answers result is the same. No worry about it.
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Enthalpy

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Re: Swapped Electrodes at Copper Plating
« Reply #7 on: July 02, 2018, 03:09:54 AM »

With 1.5A a few seconds, you can't dissolve 10µm of metal. The current is the limit.

"Just reading in the Internet about Chromate makes you paranoid": one has to interpret safety warnings. You might start by reading the Safety Data Sheet for sodium chloride, or for ethanol. It helps relativize the other compounds.
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pcm81

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Re: Swapped Electrodes at Copper Plating
« Reply #8 on: July 13, 2018, 11:08:05 AM »

You might start by reading the Safety Data Sheet for sodium chloride, or for ethanol. It helps relativize the other compounds.
LOL, that is actually a pretty clever advice: http://www.sciencelab.com/msds.php?msdsId=9927593
LOL at bold

Section 7: Handling and Storage
Precautions:
Keep locked up.. Do not ingest. Do not breathe dust. Avoid contact with eyes. Wear suitable protective clothing. If ingested,
seek medical advice immediately and show the container or the label. Keep away from incompatibles such as oxidizing
agents, acids
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Anolym

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Re: Swapped Electrodes at Copper Plating
« Reply #9 on: July 21, 2018, 09:35:59 AM »

Thanks to everyone for your *delete me*
Im a Chicken in those Things. If something goes wrong, I expect the worst. I am a bit hypochondriacal in such matters. Im still cleaning surfaces and Things in my room to this day. Probably I Just have to cool down and Take IT easy  ;D

Probably I would even be still living If I swallowed the solution because the produced Cr6 would bei in the area of 10 - 30 mg. This isn't enough to kill anyone I think  ;)
People who are working in chrome plating shops will probably exposed to more Cr6 in one day.

Thanks for all your *delete me*

Anolym
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