Jade asked whether we could standardise a recipe. I suspect that there are any number of effective procedures for making our CS, but the problem is knowing which variables are important and how they effect the product.
A series of experiments are in order, *some* of which would be fairly simple for anyone with a little time to spare. I'd appreciate anyone's comments and criticisms, or referrals to people who've already done the work!! 1) Current flow rate (in milliamperes) vs. electrode spacing: -----a) in pure water -----b) with 1 through 10 drops of a 3x weaker saline solution. This would give us an idea on how sensitive the process is for spacing, and how the shape of that curve varies with different electrolyte concentrations. 2) Current flow rate vs. wire gauge or surface area. -----a) for a couple of different gauges of wire -----b) with more or less of the wire submerged -----c) with wire flattened to increase surface to volume ratio -----d) in pure water and with some saline concentration This will give us some clues as to what effect surface area has on production rate, and whether geometric concerns that would effect electric field densities at the electrode surface are important. 3) Measured silver concentrations (in ppm) vs. total current flow (in milliampere hours) -----a) in pure water and with saline -----b) with as many different electrode geometries as seem important after doing experiment #2. -----c) with 2 or 3 different electrode spacings This would tell us if concentration is a direct, or at least somewhat predictable function of current and time. We might find that production rate is not linear with current, for example, or that a certain minimum current is required to produce anything at all. 4) Finally, particle size vs. all of the above. -----a) particularly the effect of using salt vs. pure water, and... -----b) the effect of deposition rate on particle size Experiments 1-3 require a simple current meter, and the ability to measure wire size and spacing and calulate electrode surface area. The last two, concentration and particle size, would require some analytical resources: I understand there are labs that will measure the ppm of silver in your samples for a fee. Or, I hope, there is a simple chemical assay, like a titration, that you could do on your own bench. As for particle size, you could allways use an electron microscope! Er... Well we had one where I *used* to work! Other than that, I don't know whether you could use an optical microscope or if there are optical techniques (scattering, absorption?) that could yield a measure of particle size. Anyway... I would hope that after doing some of the initial measurements, a picture would begin to emerge of which variables have the strongest influence on production rate. You would then not have to test as many variables later on. I think measuring concentration will be necessary no matter what. I just hope I can find an inexpensive way to do it. I suspect that we can be satisfied if we test only a few samples at the end to see what particle size is produced under conditions that seem to be optimal. If there is a huge variation, say, between saline vs. no saline, then a little more work might be in order. Anybody got a research grant!! <grin> I've made some CS and have been taking it for a week or so. Too soon to tell how much it is helping... Mike [Mike Devour, Citizen, Patriot, Libertarian] [[email protected] ] [Speaking only for himself... ]
