Re: DIY - CS Generator - build & parts list

RE: I think that I would rather use 4 9v batteries if I was doing it this way .
I think there are many advantages in having more voltage, though I'd prefer a voltage controller as this could be used to overcome the ramp-up stages in processing so as to keep the cell at optimum potential.


RE: Batteries can be hooked together... people could get away with using just two 9v battery clips.
Having used multiple 9v batteries for majority of my first year, I found it to be a bit tedious in terms of charging, connecting etc, and so I moved to a fixed power source as well. That said, I can't fault the use of batteries in the beginning stages personally, as this proved quite helpful in getting the job done and in gaining familiarity with the process.

I  agree that using a voltage converter/controller is the better option and not having batteries going flat part the way through the process. I dug out some older rechargeables at first and charged them but never used them in the end.

I have one of these:

The daughter board plugs into the two black 8 pin terminals which is how it is supplied. However the LED display is below the top of some of the other taller components which would prevent it from fitting in a case. I have the connectors to extend that daughter board so that I can connect it in a case.

A voltage converter which seems to do what is necessary. Maximum 38 Volt output from a 12 Volt regulated power supply with a simple DC split cable to power that and the magnetic stirrer. It can control the current too which I intend to test before making a firm decision on whether to stick with it or add a CLD. My calculations show a 2.8 to 3.8mA maximum current is needed for the Silver surface area that I will be using. Couple that with a 38V starting voltage should do what is necessary. The limits on the device are 1mA/1mA steps so 2mA, possibly 3mA max would be the closest choice unless I add a diode. I will have to see how tightly it can control the current. Initial testing suggest that the CV diode lights showing constant voltage but when the set current level is reached the CC diode lights and the voltage is reduced to compensate. Starting at 38V should provide plenty of potential to play with and prevent it reducing to too low a value.

RE: What are your thoughts on the EMI from the magnetic stirrer? Have you ever tested it? Using something like a portable AM radio and putting the earphone leads next to the stirrer and adjusting the frequency and listening for any noises.
I ran tests several years ago in my own attempt to determine whether there were advantages to using a magnetic stirrer over a mechanical one. And so I setup several super concentrate colloidal silver solutions along powerful magnets in hopes of observing the changes this would have over those stored in a none magnetic area. To which I'd add, the results showed no discernible differences between both samples. And so I didn't pursue the matter further.

In addition to this, I also tried running tests during full moons(super periods) to monitor what effects this might have on readings. But also found no discernible differences in processing between a full moon, new moon or quarter phases. And so I did not pursue this particular matters further as well. - ps. the process readings were +/- .05v between electrodes and times were in seconds

I do not think that it is possible to work out the quality directly from the voltage/current, only expensive testing could really do that. Limiting the current helps prevent large particle formation but whether an electric field could promote agglomeration or other negative effect is a bit of an unknown. It seems more a case of doing everything to promote high quality CS and hoping for the best outcome. Doing things such as stirring but it can never be known for certain how small the particles are or how many have agglomerated. My reading suggests that Silver is diamagnetic and tends to be repelled by magnetism which should be a helpful property. I did see how Silver can be levitated by magnetism. I must point out that it was not the magnetism that I was concerned about for the reasons that I stated as the magnestism should be beneficial. It was the electric fields that concerned me from the electronics. I also wondered how well commercial magnetic stirrers were shielded as very effective shielding adds costs. I did look into shielding and it seemed quite a complex situation with so many variables ie different fields, frequencies and different shielding materials. Unfortunately I do not know what I would be shielding against as I do not know what frequencies are present and no equipment to test for it. I did do some very basic testing using an AM radio but those kinds of frequencies are only a very small range. The PWM controller does state a PWM frequency of 25kHz but that does not give the electric fields and harmonics that the electronics will emit. This is all so crucial because it is so close to the CS which is why I am so concerned about it. It is not to say that a commercial magnetic stirrer would be better than the one I want to make, it could be much worse as most of it is Chinese. The PWM unit is inside a thin aluminium case with regulators which are bolted to the sides of the case to dissipate heat. The case is overlapped where the case halves meet which is nice but the end plates are only screwed to the body with a thin piece of rubber for neatness which could allow some leakage. Overall I am fairly pleased with it's construction but it is obviously leaking some EMI but I do not know how much. Attaching a ground to the securing screw of the aluminium case might help a bit but it does all need to go inside a thicker outer case to help with shielding. It's finding something of an ideal size, there are hammond aluminium cases of 250x250x100e mm however that is a bit bigger than I would like, 180 would be more ideal as the 2 litre erlenmeyer flask base is about 160mm in diameter. Many of the smaller cases of a closer size do not have enough height to house the PWM unit and the fan and space for the neodymium magnets.

The PWM controller is like this one:

http://www.ebay.co.uk/itm/DC-SoftStart-Reversible-Motor-Speed-Control-PWM-Controller-PWM-/401219500958

RE: I prefer the idea of a magnetic stirrer to a bubble mixer as I am not convinced about introducing air into the process or dust for that matter.
I discovered numerous advantages in the use of a magnetic stirrer in that it can greatly improve purity by isolation. Though it was in the mainstream observations that I discovered the greatest benefits by dispersing ions away from the anode, which in turn, discouraged the formation of oxides while promoting the reduction at the cathode. - keeping in mind that this may only be significant under the heat reduction method, rather than with room temperature processing.

Interesting, do you use a magnetic stirrer with a heat plate then? I have some big doubts about the cheaper magnetic stirrers as I have stated. I think I would rather overdo it and ensure that EMI is kept as low as possible. I have thought about constructing a small faraday cage with some wire mesh around the electronics and grounding that to reduce any emitted fields. Without the equipment to test for EMI it is so much uncertain guesswork which I do not like.

RE: What is the reason for the wide separation of the electrodes? Is it to avoid the possibility of the doubled/bent electrodes from coming into contact with one another? From what I have seen, the recommended separation is only meant to be around 20 to 25mm or approx 1". However when using a bend in the electrodes it makes it harder to avoid them touching one another and shorting.
There are misconceptions with regard to electrode spacing in that people are often under the impression that a common distance should exist between them. When in reality, the electrode spacing is completely proportionate to the efficiency of the electrolytic cell. ie, when the process(of colloidal silver) begins, the conductivity of the cell is quite low(near zero). And thus the electron flow(or current) does not carry over from the cathode to the anode very effectively. And so there are a few things we can do to mitigate this:

1. We can raise the voltage
2. We can move the electrodes closer together
3. We can raise the temperature of the solution.
4. We can alter the conductivity(seed) of the solution.

    That said, on the first option(1), I'd be careful, as DC voltages in excess of 60v could potentially harm someone.
    The second option is quite safe, and I've been making us of this in conjunction with no. 1 for the past few years.
    The third is also quite viable, in that it can also help control the addition of chemical reduction during processing as well as raise the initial conductivity. Though above this, heating ones solution can do much more, in that it can not only raise the overall solubility and saturation levels, but also brings with it the addition of thermal chemical processing(changes) which can be used to further alter the size and shape of the particulate.
    The fourth and final option(to my knowledge), is quite common, though I don't use it personally, as my preference is toward the ionic side, which has proven to be best, made fresh.

Therefore and with that being said, the interesting part about voltage in electrolysis is that the voltage is merely a carrier from which the current can do its work. And so the extent(within limits) in which the voltage will most often affect Colloidal Silver processing is that of the ramp up stages. As the remainder of the process will be subject to a voltage drop(between electrodes) due to the effect of current regulation.

In relation to this, you can experiment with the effects of voltage and electrode positioning by monitoring the current and voltage(between electrodes) during the ramp-up stage. Which will in most cases, provide great visual feedback on the dynamics of the electrodes within the cell.

I am keeping the voltage reasonably high at the beginning, comparable to or higher than most commercial CS generators from what I have seen. I think it should be adequate for the quantities that I require. The silver wire that I purchased is 2mm diameter and long enough to provide a loop in the flask to maximize the surface area. That is where the risk of the electrodes touching comes into it and what I wanted to avoid. I have calculated  2544mm^2 or approx 3.9 square inches.  I did not want to mess around with seeding at the beginning.

RE: I thought about using a terminal block to retain the electrodes and prevent them from swinging into one another. That would allow the electrodes to be locked with a screw. I have some already and one size I have seems to fit quite nicely. I am using a 2 litre wide mouthed (70mm) erlenmeyer flask so separation distance is a bit limited
I personally think such topics will depend heavily on how far down the rabbit hole one is willing to go, in terms of equipment and processing methods. Though my preference has been to use custom made PTFE lids with Versilic stoppers to suspend my electrodes with. This in turn, allows for quick cathode changeouts and the ability to turn the cathodes on an offset so as to alter its distance from the anode accordingly.

I did look at silicon stoppers myself but the price was jaw dropping so I dismissed the idea. I like silicon but not at the price they were charging.

The terminal blocks should sit nicely above the rubber plug, the rubber plug should hold the electrodes fairly securely in a horizonal direction.  I got those at an unbelievable price 4x for less than the cost of 1 anywhere else, £2.79 for 2+del so I purchased 4. Nice and deep as well to hold the electrodes but not strong enough to prevent rotation. The Terminal block should hold them and prevent rotation and any danger of them twisting and touching. That would short the dc power converter which might damage it. The terminal block screws can be released easily to remove the electrodes. It should just pull off when the screws are released.

http://www.ebay.co.uk/itm/322286319994

ATM it's the stirrer which is holding it all up. It's not functional until I have a working stirring system. The case is the main problem. I think I will have to go with a Hammond aluminium case of 250mm to fit the parts in. It's quite a bit bigger than I want or need. Then there is whether to go with unpainted or black powder coated. Knowing aluminium and how ugly it looks I might have to go with the black powder coated case. I am not a fan of black cases which is why I am hesitant. I also need a case for the DC Buck/Boost Converter. Fitting the display, buttons and LED's is proving difficult not being able to see the stuff that I have to choose from. I would like some form of cover for the LED 4 digit display but I do not know the name of the part that I am looking for. [EDIT] LED/LCD Bezel but I cannot find one of the correct size because they are all too large. The buttons also need extending and mounting and the LED's need some form of extension to the case [EDIT] they are called light pipes. You can see from the picture that I have the connectors needed to extend that display/control module but it is how I am going to mount that neatly with the other buttons etc.

Thanks for your helpful feedback again.