I was looking into gelatin usage and found two formulae, or rather
scenarios of usage. Since they looked superficially like a contradiction, I tried to work out how they align. I have a habit of writing down such findings for later reference, and I might as well share them with you. I have given my best to be accurate and concise and I hope what I say is favourably welcomed by our chemistry experts.
In the forum there is reference to
gelatin (assumed sheet variety) in places and explicitly to
powdered gelatin in other places. The last time I have bought gelatin they only had
sheets - this was decades ago. Those probably dissolve less easy, so they powdered them. By the looks of it, the here referenced product “Knox“is of the latter variety. The shops here also have all sorts of
cake jellies which contain other wonderful ingredients unwanted for making Colloidal Silver. Beware of that.
Without further ado, let´s look at the formulae: (Note: the
preparation itself is left aside for the moment. For this exercise we are just interested in the
concentrations needed for an imminent production run). In the following, DW = distilled water, Colloidal Silver = colloidal silver, gelatine = gelatin (different local writing), premix = gelatin/DW solution (a.k.a. stock concentrate, a.k.a. gelatine solution);
This is just for completeness (we need it further down) the
Formula for runtime calculation (Faraday’s Law)Source:
https://www.cgcsforum.org/index.php?topic=47.0Faraday's Law (minutes to run cell to desired PPM)
PPM * <liters> * 15 / <cell current(milliamps)>
Formula #1: calculating the amount of premix source:
https://www.cgcsforum.org/index.php?topic=4965.0Note: all the formulae are gauged for
1 liter of final product. This is the scaling factor for calculating the required amounts.
Preparation: 1 l of DW and 4 g gelatin (it is not explicitly stated, but I see no reason why sheets and powder should not work alike. There is nothing on the package that hints at any difference beyond their physical appearance.)
Application amount: 20-40 ml per liter of Colloidal Silver
This premix is recommended
for low PPM, such as 20-40 PPM.
For high strength like 320 PPM using
4g of gelatin into 1 l of DW is suggested.
Since this is exact same the concentration as the premix solution, we might use premix
directly without adding any more DW.
Note that this formula does not directly take the
target PPM into account, unlike the subsequent formula, so we could rather call it a
postulate.
As different to the above formula, the subsequent (probably later expressed) formula prepares gelatin
freshly for an imminent production run.
Source:
https://www.cgcsforum.org/index.php?topic=47Lacking an „official“name, let´s for the exercise call it
Formula #2: calculating the amount of dry gelatin, PPM correlatedApplication amount:Gelatine (mg):
PPM * x ml (Colloidal Silver) / [160...80 ]
meaning between divide by 160 to divide by 80 (2x as much)
Kephra is a bit more specific here about the span:
https://www.cgcsforum.org/index.php?topic=6493.msg52748#msg52748They are constants calibrated to give you a guesstimate of how much gelatin to use.
The formula means choose a number between 80 and 160. I recommend 80.
A little more does not hurt obviously, as long as we are not into jelly-making.
And further down:
The formula is for dry powdered gelatine.
So up to here there is nothing new.
I plugged both formulae into a spreadsheet and juggled with the numbers a bit.
Formula #1 uses
4g gelatin per liter. Phrased differently, this are
4g / 1000 milliliters, which in reverse translates to
4/1000 g per millilitre or
0.004 g per ml. All the same.
So expressing formula #1 in
grams instead of millilitres we find that if making 1 l of Colloidal Silver we apply 20-40 ml of premix, which corresponds to 0.08 to 0.16 g of gelatin (dry matter) respectively. We´ll need that later.
If we consult formula #2 (using 20 PPM) we get 0.125 and 0.25 g of gelatin (dry). We see, the numbers are close. Obviously formula #2 comes out a bit more generous overall.
It comes to the restless mind to use formula #2, but express the amount of gelatin (solved) in
ml premix @ 4g/l DW rather than grams of dry matter.
Formula #2 originally spits out
mg (gelatin) per ml (DW), which equals
g (gelatin) per l (DW).
So for clarity, let us reformulate above formula as
formula #2a in
grams instead of milligrams:
Gelatin (g):
PPM * x liter (Colloidal Silver) / [160...80 ]
Since 1l of premix contains 4g of gelatin,
1g gelatin is contained in 250ml of premix.
Note that in this context
liter (Colloidal Silver) is assumed to be equal to liter (DW) (see later...)
Replacing
g of gelatin in formula #2 with
ml of premix (containing the very same amount of gelatin) we land at:
Formula #3: calculating the amount of premix, PPM correlated (Note: at this point, do not confuse
premix liquid preparation and
application thereof during electrolysis. The preparation method remains unaltered. I am talking about the latter here.)
Premix (ml) into Colloidal Silver: 250ml/g * PPM * x liter (Colloidal Silver) / [160...80 ]
Let´s put our formula to the touchstone using extreme values (1l Colloidal Silver assumed). Note formula #2 specifies an upper and lower range. Premix contains 4g gelatin per liter.
Test scenario A: 20 PPM.Formula #1: premix postulated as 20 ml to 40 ml
Formula #3: premix calculated as 31.25 ml to 62.5 ml
The amount of additonal H2O introduced by adding premix is negligible as we will see later.
Test scenario B: 320 PPM.Formula #1: postulates
4g gelatin into 1 liter of DW(freshly prepared) or
1 l of premix straight (and no extra DW)
Formula #3: premix calculated 500 ml to 1000 ml (Note: the greater value is the recommended one)
neat, huh?
Both formulae converge nicely, however the amount of additonal H2O introduced by adding premix is no longer negligible. If no counteractive measures are taken, the targeted PPM values will be lower than planned by a significant amount.
This formula will work for
all PPM target values, but you have to either
reduce the amount of DW according to the amount present in premix or
adjust the Colloidal Silver volume values (= total H20 values) in the runtime calculation (to 2 liters in the 320 PPM case). The volume of
gelatin powder itself in the premix, compared to H2O’s volume, minute and thus negligible.
Knowing that, formula #3 could be further altered so that it takes the added H2O content into account and displays the difference (i.e. additional DW to be added) by simply subtracting the two volumes.
(Note: all the previous formulae assumed that, for all practical means, the only H2O introduced comes from the DW added. In other words, 1 l Colloidal Silver = 1 l DW).
The final, water corrected, universal formula would thus be:
Formula #4; calculating the amount of premix, PPM correlated and H2O corrected:
(Again: do not confuse
premix liquid preparation and
application during electrolysis. The preparation method remains unaltered. I am talking about the latter here.)
Premix (ml) into Colloidal Silver: 250ml/g * PPM * x liter (Colloidal Silver) / [160...80 ]
DW needed = x liter (Colloidal Silver) – premix (ml) / 1000 (since it is expressed in ml)
The volume of the gelatin powder is minute and can be neglected. Test scenario A: 20 PPM. additional DW = 0.96 l resp. 0.93 l
(for all practical means: 1 l as expected)
Test scenario B: 320 PPM. additional DW = 0.5 l resp. 0 l (zero). As expected.
And just for the crack an in-between value:
Test scenario C: 100 PPM. additional DW = 0.84 l resp. 0.68 l.
Example:Let’s make ¼ l of Colloidal Silver at 200 PPM, using premix
formula #3 gives us 78 ml and 156 ml of premix to have the required amounts of gelatin.
If we, as usual, put ¼ l of DW into our beaker, this gives us a total water content of 250+78=328 ml resp. 406 ml.
If we don´t consider the added water, we get from Faraday:
150 minutes (current chosen 5 mA) and think we now have 200PPM.
Fact is, we have 328 ml resp. 406 ml of water and should run the process 196 resp. 242 minutes.
Aside: Faraday’s Law rehashed
Faraday's Law (PPM to minutes to run cell)
PPM = <cell current(milliamps)> * < run time (minutes) / (<liters>*15)
Conversely, after 150 minutes (rearranging Faraday’s law) we only have PPM numbers of 150 PPM resp. 123 PPM.
While we still made high strength Colloidal Silver, it will nowhere near have the PPMs we expected. (This all under the precondition that all PPM numbers are reached under optimum conditions anyway, which we cannot control or verify)
Verdict: For low PPM values it is impractical to weigh out milligrams of gelatin powder. The premix solution is a nice solution (pun intended) for this problem, because it makes the handling of the small amounts needed more reliable and repeatable. The extra H2O introduced by the DW contained in the premix is negligible due to the small overall figures.
This way of going about is also very convenient in that it eliminates the need for the time consuming rigmarole
gelatin preparation involves every time and also the need for a
precision balance that can handle milligram amounts reliably. In comparison, obtaining a few syringes or a measuring beaker for measuring millilitres is way cheaper.
With growing PPM values however, the extra H2O content introduced by adding so many millilitres of premix (or actually: the DW
contained in premix) starts to skew the PPM values, where on the upper end of the scale (say, 320 PPM) they will be lower than expected by a factor approaching 2. This demands either a
reduction of the amount of DW you add (in the extreme case
zero), since the formula does not know about the additional water, or a correction of the
electrolysis run time (
https://www.cgcsforum.org/index.php?topic=4965.0, post #13), plugging the total H2O value into the formula.
[I don´t recall seeing this time period being called so anywhere in the forum, so I took the liberty to invent a name. This name describes the time period, during which current is active and it does not include any time needed for alleged ongoing curing processes.]
In the extreme case (320 PPM),
electrolysis run time would thus come out as approaching
double in order to achieve the desired PPM value. Both methods are easy and don´t involve much math.
Considering those peculiarities, the premix route can be taken for all PPMs.