The diodes only work when wired correctly. Meaning... you won't get any current limiting if they're connected backward. Which you can easily observe by wiring a multimeter into your circuit and measuring the load(I like using a small light-bulb). - which I'd highly recommend btw. That said, ideally, you'd want two(2) multimeters in your setup. (1) to watch your voltage drop AND (2) to watch and monitor your current load. As this will provide an wealth of information insofar as monitoring and improving your craft. Not to mention, gaining a familiarity with the dynamics of colloidal silver processing.
Here's a simple diagram showing how you'd wire a single current limiting diode vs. multiples into your circuit
PS. I like diodes for their simplicity. ie, I make CS using voltages ranging from 85v down to 30v. Of which, I simply pick the appropriate diode for the job(44mAh in my case) and be done with it.
Hope this helps
The current rating is proportionate to your electrode size. More specifically your Anode(positive electrode). And the rule of thumb on this is typically 1mAh per/sq. inch of wetted electrode. - This has proven to be a good rule to follow in most cases.
I am using 12 awg silver wire with 3" immersed in the water. How do I calculate the surface area?
As for the cathode, it's usually best to try and keep an inferior Cathode to Anode ratio(1:2 or better). Which is a very good way to establish and maintain a safe current draw on your Anode. Though there is no rule of thumb here as the parameters will change according to electrode size, temperature and initial solution volume.
You mean, if the cathode is 4" then the anode must be 8"?
Is it alright to use silver wire for the anode and copper wire for the cathode?
That said, You are right on the relationship between current(mAh) and particle size. Though I'd also point out that there are physical limits to the minimum potential size a Colloidal Silver nano-particles can possess which I believe is important to recognize prior to committing to a given process.
ie, lower current means longer run-times. Longer run-times means more oxide formation on your electrodes and in solution. And so the trick with such things, is to balance the parameters of the process so as to produce the best possible solution for your needs.
By "oxide" do you mean the black crud that forms on the electrodes?
Sometimes I forget to check the cooking and when I come back I see lots of black crud already. I stop the cooking and just filter out the black crud using two layers of coffee filter paper. Is it alright to do that or is the CS unusable once black crud is formed? I have never been able to make CS without black crud being formed.
Surface area of a cylinder: A = 2 π r h + 2 π r 2
Stock = 3" @ 12 AWG
12 AWG = 0.08080" dia.
Solution: A≈0.77 sq in.
Conclusion: .75 to 1mAh is acceptable
On the topic of anode /cathode ratio's, a visual differentiation is most often all that's needed. One common method of doing this is to gang several wires on a silicon stopper and use a smaller dia. cathode.
As for using other materials for the cathode, I used to use food grade stainless wire until I discovered that it affected the taste of my solution. And so I stopped doing this in favor of silver electrodes all around. However, I'd add that my own method of making CS involves processing at 105c, and so this may have contributed to the results. - your mileage may vary.
Correct. In my opinion, any cross contaminants such as the formation of oxides will come at the cost of the particle size/quality. That said, the formation of oxidation on the cathode is consequential to the electrolytic process. However, there are ways in which you can eliminate this either by, heating your solution to the point of reducing the ions into elemental silver and/or with the use of additives, as well as a few other not so popular methods.
PS. I'd also recommend(if you haven't) the use and admission of a multimeter to monitor electrical parameters during processing. ie, one multimeter is helpful whereas two is ideal as this will allow the monitoring of voltage and current as things move along.