Interesting post John. I have been wondering about HVAC processes. Yours sounds like a beauty. I'm going to make one. I want to compare the CS made from AC vs DC both LV and HV, and to this end have been reading at the university science library. Perhaps I can answer some of your queries in part, but I must say that this area in science seems quite vague and most study of metalic sols took place before 1950 and can be contradictory, at least to my limited capacities. It should be recognised that AC and DC voltages produce different forms of silver, AC ; elemental metal particles with no charge, DC ; ionic metal particles generally Ag+ but may also be Ag++ or even Ag+++ and probably some elemental silver as well. The biological activities differ between the two products. First, an oscillating electric arc at low current will produce small particles, of which 19 - 52% will be silver oxide, I suspect this will be your milky cloud. According to one of my notes, a certain amount of silver oxide will aid colloidal stability. Interestingly Svedberg stated that, silver and perhaps also mercury may produce metal sols by boiling or irradiation by uv light under water. The irradiation leads to the production of hydrogen peroxide in the water which oxidises the metal into solution, silver oxide then separates as the concentration increases, having low solubility in the colloid form, which then, in turn, is reduced to metal by the same uv radiation. (perhaps Ionic silver colloid could be stableised by the addition of a small amount of hydrogen peroxide, boy what combination!) Silver sols were obtained early this century, first by DC arc (30 -110 V 5 -10 A) then by HFAC 10,000 - 10,000,000 Hz arc with little of the decomposition of the dispersion medium that plagued DC arc. I have no idea of the bioactivity of silver oxide. As to the particle size and colour of CS, Otswald formulated the rule, that the variation in colour of metal sols is due to a shifting of the absorption maximum (of visible light) towards the regions of longer wavelength with decreasing degree of dispersion and Mie found that the colour displayed may be used to characterise the particle size. Although these rules as well as those of Rayleigh depend on particle shape it seems they may be applied generally to colloidal silver. Thus: as the wavelength of absobed light increases from 400nm to 730nm violet - inidgo blue - blue - blue green - green - yellow green - yellow - orange - red - purple light is absorbed, leaving the corresponding transmitted light : yellow green - yellow - orange - red - purple - violet - indigo blue - blue - blue green - green, to be observed. Clear suspensions absorb near uv and uv light and therefore transmit all visible light, more or less, and are of a correspondingly smaller size.
I have not experienced yellowing myself, but if that means a shift from a lighter to a deeper shade then i suspect an aggregation of particles, as is flocculation and dropping out. This most likely will proceed until an equilibrian has been reached, and then should be relatively stable. There is more that I would like to discuss on this topic and some questions I would ask of those more familiar with these matters, but for now, my regards. Ivan > >A High voltage AC maker can be made using a used Neon sign transformer. >Let me give you an idea of the way that I generate CS. For years I used the >9v battery method. I have now found that a used neon sign ballast (9000v) or >(12,000v) that you should be able to pick up from a sign shop for about 20 >dollars, and a couple of pure silver wires, and a couple of alligator clips >is really all you need to make high quality, high voltage AC Silver Colloid. >It can all be done for under $40.00. If you insist on a new ballast, it can >cost you over $100.00. >Just submerge one silver wire in the water, and suspend the tip of the other >electrode about 1/8 inch above the surface of distilled water. When you >turn on the ballast,you will get a momentary blue arc, and then a "cone" of >water will be drawn up the tip of the electrode about 3/8-1/2 inch. Leave >this for about an 1/2 hour in 1/2 gallon of distilled water. If it >starts to arc before the 1/2 hour, and you let it arc for a while, then the >colloid starts to get a cloudy, milky appearance. Even though this "milky" >product still appears to be stable, (no dropout,or yellowing) I am not sure >of what particle size is being made during the arcing process, so I do not >let it arc, Maybe someone else on this list will know what size that type >of particle is. I don't. I also don't know the concentration that it makes, >nor how to test at home for concentration. I do think it is somewhere in >the neighborhood of about 5-10ppm. I do know that by not letting it >arc, I am making a perfectly acceptable product to me, which seems to be >vastly superior to the old 9v battery process. It also seems to utilize the >silver electrode much more efficiently. It is obviously much more stable and >exhibits a strong Tyndal effect, and does not seem to "drop out" or get more >and more yellow upon sitting. ( I think yellowing and dropout are a sign of >larger particles) >If you are interested in making your own CS, you may find that this simple >arrangement can make a yellowish product that compares much more favorably >to the product produced by the high quality 10,000v AC machines you may have >heard about on the internet selling for over $700, than does the product >produced by the 30volt >DC (9v battery process) > >John -- The silver-list is a moderated forum for discussion of colloidal silver. To join or quit silver-list or silver-digest send an e-mail message to: [email protected] -or- [email protected] with the word subscribe or unsubscribe in the SUBJECT line. To post, address your message to: [email protected] List maintainer: Mike Devour <[email protected]>
