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Inducktion

Mon Apr 04 2011, 08:54PM

Registered Member #3637 Joined: Fri Jan 21 2011, 11:07PM
Location: Buffalo, NY
Posts: 1068

Hey all.

Recently, I tried the DIY etchant solution that consists of vinegar, Hydrogen Peroxide, and salt.

Well, it worked, too well. It dissolved the copper traces off completely, but also dissolved off the sharpie marker!

Poop.

So, I was left with a bottle of blue stuff.

Annddd.... I thought about it for a minute, and decided to see what would happen under electrolysis!

Some odd stuff happened.

They are the same exact type of metals on each end. (aluminum)

The negative electrode started to fizzle, A LOT. And, some weird dark brown reddish stuff formed on it, easily scraped off with a pair of pliars.

The positive electrode, on the other hand, didn't do much, but the electrode was plated with copper! Pure, brassy copper. Interesting!

So, the blackish brown stuff? If intensely electrolysis-ised, (meaning putting a dot of the blue solution on it and putting the positive right on it) some black stuff formed. And, using a flyback (yes, I know, this is all really dangerous but nothing bad happened, and I WAS wearing safety glasses at the time) the arc glowed an intense, pleasant orange color from the black gunk.

What's going on here? Electroplating copper was pretty neat.

Bored Chemist

Mon Apr 04 2011, 08:59PM

Registered Member #193 Joined: Fri Feb 17 2006, 07:04AM
Location: sheffield
Posts: 1022

It's complicated, but I think you probably got copper on both electrodes. ( the brown gunk is probably copper too.)
A bit of information about the voltage/ current etc would help.

Inducktion

Mon Apr 04 2011, 09:04PM

Registered Member #3637 Joined: Fri Jan 21 2011, 11:07PM
Location: Buffalo, NY
Posts: 1068

Bored Chemist wrote ...

It's complicated, but I think you probably got copper on both electrodes. ( the brown gunk is probably copper too.)
A bit of information about the voltage/ current etc would help.

24 volts, drew around 3-6 amps. Just lead acid batteries. Also, I forgot to mention, that the blue stuff has turned cloudy, and is now a sort of almost greenish color.

James

Tue Apr 05 2011, 10:41PM

Registered Member #3610 Joined: Thu Jan 13 2011, 03:29AM
Location: Seattle, WA
Posts: 506

Well if nothing else you have an easy way of recovering copper from the spent etchant. I've been tempted to try that with my copper chloride mixture.

Inducktion

Tue Apr 05 2011, 11:35PM

Registered Member #3637 Joined: Fri Jan 21 2011, 11:07PM
Location: Buffalo, NY
Posts: 1068

James wrote ...

Well if nothing else you have an easy way of recovering copper from the spent etchant. I've been tempted to try that with my copper chloride mixture.

The orange stuff, now that I go back to it, almost looks like rust, but that can't be! The clip leads are aluminum, and there was no steel of any sort introduced into the solution.

I think it's dirty copper, but yeah, this is still kind of cool to find out.

pauleddy

Thu Apr 07 2011, 01:14PM

Registered Member #2909 Joined: Wed Jun 09 2010, 12:31AM
Location: fort belvoir, Va USA ( south of DC)
Posts: 145

The green solution is copper acetate, I have made tones of this salt, it make nice crystals, but is not vary water soluble It took me weeks to grow a small quanty, it great for electroplating. And if you want you can decompose it and get vary fine copper powder, and distill the acetic acid out and gett near glacier acidic acid fun stuff

James

Thu Apr 07 2011, 06:48PM

Registered Member #3610 Joined: Thu Jan 13 2011, 03:29AM
Location: Seattle, WA
Posts: 506

The orange stuff is probably some sort of copper compound, not pure copper. At one point I coulda told you what it was, but it's pushing up on 15 years since I've had a chemistry class so some of it has escaped me.

Inducktion

Thu Apr 07 2011, 07:48PM

Registered Member #3637 Joined: Fri Jan 21 2011, 11:07PM
Location: Buffalo, NY
Posts: 1068

pauleddy wrote ...

The green solution is copper acetate, I have made tones of this salt, it make nice crystals, but is not vary water soluble It took me weeks to grow a small quanty, it great for electroplating. And if you want you can decompose it and get vary fine copper powder, and distill the acetic acid out and gett near glacier acidic acid fun stuff

What is copper acetate good for? o_o

And, how would I go about decomposing it to get the fine copper powder?

pauleddy

Thu Apr 07 2011, 09:37PM

Registered Member #2909 Joined: Wed Jun 09 2010, 12:31AM
Location: fort belvoir, Va USA ( south of DC)
Posts: 145

it can be used for electroplating, what I did, fill on of those little co2 canister with powdered copper acetate then heat with a propane touch in till no more steam come out, a warning the steam is hot acetic acid vapors and fine copper powder that will combust and smell like strong vinegar and burns your nose. Donâ€™t get it too hot or you will start melting the copper. After you let the canister cool, and them pour out the copper powder in to a container. I did this to make strong acetic acid, itâ€™s a poor over completed way to do it but it works. And a fun you get to dissolve copper, crystallize, grind decompose and distill.

Ash Small

Thu Apr 07 2011, 09:41PM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

Inducktion wrote ...

.And, how would I go about decomposing it to get the fine copper powder?

I'd guess he means heat it up, Inducktion, and drive off the glacial acetic acid, which can be condensed. (but don't take my word for it)

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