a couple of questions regarding silver production

[Art]

With the SilverTron Elite, if you are not using a stirring device, what is the maximum milliamp setting you can use with a silver rod and what is the maximum setting if you are using a silver bar as available from the SilverTron store? Does the gauge of the rod matter?

I started using my SilverTron Elite with a hot plate stirrer and I can't remember ever making a batch without the stirrer on, so these are two things I was wondering about .

Art

[kephra]

That depends on temperature and the amount of submerged anode area.  In general, without a stirrer, you can increase the current until you detect 'smoke' coming off of the anode.  Start at 3 ma and go up from there.  With a stirrer you can go the full 15ma even with just a wire anode.

Without a stirrer of some sort, you will get plating on the bottom of the flask underneath the anode.  This should be removed with peroxide before it becomes an opaque mirror. 

[Art]

Looks like I will have to do a little experimenting. What size silver rod comes with the Elite now?

Art

[kephra]

The wire electrodes are 12 gauge (0.08, 2mm)

[Art]

Thank You.

[Art]

Kephra,

I am currently experimenting with production without stirring and I need you to describe what you mean by the term "smoking".

I am using a moderately used  12 gauge rod for my anode to make 20 ppm in a liter of water. The rod is maximally submerged. I am using a copper cathode. At 9 ma I see a constant and growing tail coming off of the bottom of the anode. At 8 ma I see the same thing to a slightly lesser degree. At 7 ma I see what I would describe as a tail coming off of the bottom of the anode. At 6ma I see a shorter tail that does not appear to be growing and seems to stay fairly short. All of these tails seem to be trailing down toward the bottom of the beaker. My water temperature is 69.1 degrees F. I have the voltage set at the 19~20 range.
At 5 ma, it looks like no visible tail coming off of the bottom of the anode, but the previous test at higher ma showed a visible pile of particles building up below the anode. On further inspection it looks like there is a very faint tale that appears to be moving straight to the bottom of the beaker. So far it looks like 3 or 4 ma is going to be the limit at this water temperature.

Can you give me your input. What I am trying to establish is a general starting point for someone who has just opened their SilverTron and plans on running it without a stirrer/hotplate and will be using either a 12 gauge rod or a silver bar for their anode.
Thank you.

Art

[kephra]

Art,

Start at 3 mA,  if processing at room temp with no stirrer.  If made hotter, like using a hot water bath or a hot plate, you can increase the current.  Convection currents from the heat will keep the solution more uniform, but that should be done in pyrex (borosilicate) glassware, or using a water bath around a mason jar.

Even at 3mA with no stirring, you will get silver oxides falling from the electrode.  This can't be helped.  The concentration of silver ions in the diffusion layer simply reaches the solubility limit.

Going below 3mA is ok as long as you can keep the voltage up but that becomes increasingly hard.

Gently swirling the jar every few minutes also helps keep the mixture more uniform.

Here is a photo of a batch colloidal silver made at 3mA at room temperature with no stirring.

[Art]

Thank you, Kephra.

[Art]

Having always used a stirrer since my very first batch of ionic silver, I never realized how much more efficient it seems to be with a stirrer and definitely faster since you can increase the ma level right on up there.

Experimenting the last few days has shown me two things. One, I don't like using rods unless I have a stirrer. Two, if I don't use a stirrer, I would definitely only use a silver bullion bar to make colloidal silver. The bar just seems much more efficient and is definitely my preference over using a rod.

Kephra, do you sell larger bullion bars than what I have or is a larger bar just overkill?

Art

[kephra]

Kephra, do you sell larger bullion bars than what I have or is a larger bar just overkill

?
I do not have any larger bars. 

You could double up and use two bars side by side for the anode, but I believe it will be overkill using a stirrer, and perhaps marginally better without one.

[Art]

Okay, one bar it is. Thank you!

Art

[WayneInPHX]

Kephra,
...So far it looks like 3 or 4 ma is going to be the limit at this water temperature.

You are close to Min limits for both current AND temp.  75F/24C Min,  (I) would go no lower than 4 or 5 mA.   My 2 cents.

[RickinWI]

Kephra,
...So far it looks like 3 or 4 ma is going to be the limit at this water temperature.

You are close to Min limits for both current AND temp.  75F/24C Min,  (I) would go no lower than 4 or 5 mA.   My 2 cents.

Hi Wayne,  Just curious why you said you wouldn't go LOWER than 4 or 5 mA?

[WayneInPHX]

You are close to Min limits for both current AND temp.  75F/24C Min,  (I) would go no lower than 4 or 5 mA.   My 2 cents.

Hi Wayne,  Just curious why you said you wouldn't go LOWER than 4 or 5 mA?
[/quote]

"Practicality.  Very low currents require lower cell voltage. There is no concrete lower limit providing you adjust all the other parameters to fit."  - KEP
It takes a LONG time to generate.