Silver cathode or copper cathode?

[Art]

I was looking at this 2010 patent that describes a method of making ionic silver through the use of electrolysis:

http://www.google.com/patents/US20120091009

In the experiments section they used different metals for the cathode while using a silver anode. One of the metals they tested was copper and if I understand the experiment correctly, the use of a copper or aluminum cathode resulted in significantly larger size silver particles, whereas use of a stainless steel, carbon, iron or silver cathode resulted in smaller particle size.

I realize this is a completely different setup that they are using in that the voltage seems to be much higher than we are using and the cathode is located in the center of the solution and is setup to spin counter to the magnetic stirrer.

Does this mean that we are better off using a silver cathode instead of a copper cathode?

Art

[kephra]

I have used copper for cathodes, and there is no difference, nor is there any scientific reason why there should be unless you try to make high ppm ionic silver and have no sodium based electrolyte.  When doing that, the silver plates onto the cathode as crystals which do not adhere well and fall off into the solution making large particles of crystalline silver metal.  Silver will adhere differently depending on the cathode metal.  Use sodium based electrolyte and control ppm correctly and there is no problem.

[John2545]

So using a copper cathode is totally acceptable?

[Gene]

Yup, as is stainless and platinum and silver but copper is so easy to find and so cheap you don't need to consider anything else.

No metal comes off the cathode nor, with the correct amount of electrolyte in solution, does any metal plate onto the cathode.

[John2545]

Are there any free or cheap coppers available, my first thought was can I use a coat hanger? Or maybe I should go to Home Depot and buy copper wire?

[John2545]

Or maybe a penny

[Art]

I use 12 ga. copper wire from any hardware store that I happened to have in my garage. The part of it that stays in the water looks silver from some of the first batches that I made. When I clean it after each use it has very very little gray on it that wipes right off.

Art

[John2545]

Awesome thank you, that's the route I'm gonna take

[RickinWI]

Or maybe a penny

Pennies have not been made of copper for quite some time now. I think they switched in 1982.  A penny wouldn't work well anyway.

If you use a copper wire then you have to make CERTAIN that you hook your cell up so the silver is the Anode & the copper is the cathode.

[Gene]

Rick makes a good point.  IF you get the anode/cathode backwards where the copper cathode is connected to + and not -, you're going to pull copper ions into the water and yup, thats DAMN toxic stuff to not only mammals but also aquatic life.  If the cell runs long enough before you shut it down (perhaps more than a minute or two) you may also plate some copper on the silver anode and now you have even a bigger cleanup issue.

If you've run the cell backwards (wrong polarity) you have to take it down and clean everything meticulously.  There was information posted I believe by Kephra earlier this year in another topic on this forum as to how to clean up such a mess so you can search for it if this issue ever presents itself.

The simple solution is to make sure your connections are correct BEFORE you switch power on and then immediately check the polarity with a multimeter as soon as you do switch on.  This is just plain good practice to get in the habit of doing regardless what you choose to use for your cathode material.

Copper pennies have been copper plated zinc since mid-1982.  Pennies are 97.5% zinc (or there abouts) so you can see how thin the copper plating is.

Swallowing a penny can cause can cause damage to the stomach lining because of the high solubility of the zinc ion in the acidic stomach and in dogs and parrots (go figure - if they swallow one, it most likely will kill them).

[Art]

Gene,
I had to go weigh a penny to get an idea of exactly how much zinc that is. My scale showed 2500mgs so if it's 97.5% zinc, that's 2438 mgs of zinc! I take 50mg of zinc per day so that would be about 48 daily doses at one time........yeah that sounds like it could definitely be fatal for a dog or bird and definitely not good for a human. I had no idea a penny could be so toxic. Thanks for that info, I think the general public is not aware of the current composition of pennies. Good idea to not leave pennies around where an infant might be able to grab and swallow it! Infants will put many things in their mouth that shouldn't be there.

Art

[Gene]

And nickels are made of 75% nickel/25% copper alloy.

Nickel compounds are some of the most toxic compounds on Earth so nickels ain't so great either.

Dimes are solid copper on the inside with a cladding of 75% copper/25% nickel alloy on the two faces.  Quarters are the same.  Of course I'm talking recent vintage - they used to be 90%silver/10%copper (coin silver) way back when.

As kephra says, the difference between a "medicine" and a toxin, in most cases is simply the dose.

They even used to use curare as a muscle paralyzer during surgery because having the patient twitching and moving during sure isn't a good thing when the surgeon has a scalpel in his hand.  Properly administered in the correct dose its a life saver.  These days they have much better drugs for this.

[John2545]

thanks for all the feedback, guys. Could someone explain to me how to check the polarity with a multimeter as Gene was explaining.

[kephra]

Connect the red meter lead to one terminal of the power and the black lead to the other with the meter set on volts.
If the meter shows a positive number, the red lead is connected to positive.  If the meter shows a negative number, the red lead is connected to negative.