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1
Colloidal Silver Production / Re: 320ppm precipitation
« Last post by FromTheDen on Yesterday at 01:22:35 PM »
Both good thoughts, thanks!
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Colloidal Silver Production / Re: The Power Supply Unit
« Last post by aquataur on Yesterday at 07:32:35 AM »
Those units tend to create the impression that you throw them at any voltage and they do their thing. Wrong.
As mentioned earlier, any CC circuit has to digest the power it dumps. You easily cook them.

And there is nothing "constant". The datasheet even tells you the current spread.
This "constant" refers to driving LEDs and such, where the term is relatively correct.

Nothing comes without penalty.
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Colloidal Silver Production / Re: The Power Supply Unit
« Last post by Gene on March 26, 2024, 08:33:29 PM »
The problem with regulator diodes is that they drift as they warm up. They're NOT diodes. They're a JFET with a resistor connected appropriately. There is no high accuracy, temperature stable reference element in them.

If you want that with using a 2 transistor limiter, replace the feedback transistor with a TL431 shunt voltage regulator. Its a 3 pin, TO92 package.  It will require setting the sense resistor to a value where you develop 2.5V across it at the desired current.

The TL431 acts sort of like a voltage comparator comparing the sense input to an internal 2.5V bandgap reference (rock solid stable, temperature compensated).

Resistor between power and the "cathode" side of the thing. The cathode goes to the base of the main transistor. The anode side goes to ground.  The emitter side of the sense resistor goes to the 3rd terminal (shown as a terminal that comes off the body of the diode in the symbol that represents it).

In this configuration it acts like a voltage comparator. IF the voltage on the sense resistor exceeds 2.5V, current flows from the TL431 anode to ground dropping the voltage being presented to the base of the pass transistor, thereby reducing current to compensate. Conversely, too low a voltage causes less current to flow through it which raises the voltage on the base of the pass transistor and increases current flow.

Yeah, for all of a couple pennies a piece from Aliexpress.

If you download a datasheet for the TL431A (Ti.com, others), there should be an application circuit for a precision constant current sink later in the datasheet. Thats what you want.

Just be warned that the pinout of this thing is NOT the same as the transistor you'd be replacing it with!!!  Believe the TL431A datasheet (wink).
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Colloidal Silver Production / Re: The Power Supply Unit
« Last post by RickRac1 on March 26, 2024, 07:54:52 PM »
A simple solution is a "current regulator". You can get 10 or 15 mA ones for a dollar from Mouser.com plus shipping. Its a simple solution.  Search for S-103T. I used the low current ones to makes DC brain learning devices. At 1-2 mA, they were great. They are directional so do check them with a meter.

Do not trust a cheap power supply to put out 0.015 Amps accurately. I have several of them. Also its serious overkill when a $2 12volt power supply from a thrift store and a current limiter will do the same.
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Colloidal Silver Production / Re: Gelatin substitute -- sodium caseinate
« Last post by kephra on March 25, 2024, 05:59:42 PM »
I made an attempt to make high ppm colloidal gold using casein.  It failed as I did not have enough sodium carbonate in the solution to balance the acidity of the gold chloride.  This resulted in a lot of 'mozzerella cheese' with the gold. After filtering out the cheese, the product looked very good though.

On my second attempt, I used 1 ml of sodium carbonate solution for each ml of gold chloride. 
For the run, I started with 200ml of water, 3ml of Karo, 1/2 tsp of casein, 15ml of  sodium carbonate and 15ml of gold chloride. No cheese, but the gold did not reduce, as now the pH was too high.  So I added more gold chloride, until suddenly the gold all reduced. 
This took 5 more ml of gold chloride.  The result was no cheese, but great looking colloidal gold at about 800ppm.
When I attempt this again, I will try to determine the optimum ratio of sodium carbonate to gold chloride.

Theoretically, the molar ratio of gold chloride to sodium carbonate should be 2 to 1.
2HAuCl4 +Na2CO3 --> H2O + 2NaCl + CO2 + 2AuCl3  A little more will be needed to activate the reducing agent.
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Colloidal Silver Production / Re: The Power Supply Unit
« Last post by kephra on March 25, 2024, 04:17:13 PM »
...
A slightly more complex version of a current limiter is the Constant-Current-Two-Pole. It is made out of ubiquitous components.
https://www.elektronik-kompendium.de/public/schaerer/curr2pol.htm
This is the method I used for the Silvertron Junior and the Silvertron Mini generators I used to sell.
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Colloidal Silver Production / Re: The Power Supply Unit
« Last post by aquataur on March 25, 2024, 04:00:07 PM »
I see this subject comes up frequently.
I deviated from the LM317 because of the issues mentioned here already.

* both the TO-220 and the TO-92 version have a limit as to the minimum current they can be throttled down to.
* both cannot take more than 40V (not needed here)

A slightly more complex version of a current limiter is the Constant-Current-Two-Pole. It is made out of ubiquitous components.
https://www.elektronik-kompendium.de/public/schaerer/curr2pol.htm
You would probably need to employ a translator program.

It can be used as a current source or sink - hence the term "two-pole".
You can set any small current you like with unbeaten stability and use it with voltages up to several hundred volts if you like.
Use BD139/140 or similar for up to 80 Volts.
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Regarding gelatin premix, add it first and then top off for the correct amount of water.

That's the short version of my epos. It could not be any more condensed.

Regarding the formulas for gelatin:  They are all completely wrong.

Hahaha, the whole nightmare powderized ;D

Great that I had fun writing it at least. I guess in dense nebula any indicator for the right direction is welcome.
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Regarding gelatin premix, add it first and then top off for the correct amount of water.

Regarding the formulas for gelatin:  They are all completely wrong.  You cannot accurately base it on ppm or weight of silver because not all of the silver atoms need the gelatin.  Only the atoms on the surface of the nanoparticles need and indeed can even have gelatin attached.  Its like painting your house where you buy your paint according to the area you want to paint, and not the volume of the room.  Also unknown is how many layers of gelatin bond to the nanoparticle.  Is it 1 or 2, or 1/2 etc. Who knows? So whatever number you get with one of these formulas is at best a guesstimate.  Also. gelatin is not a standardized product, and varies as to molecular weight and size depending on who made it and what it was made from.  Therefore I have always discouraged weighing it, as its a waste of time.  Its the difference between a bullet and a hand grenade.  A bullet needs to be aimed perfectly, while a hand grenade only has to be close enough (20 meters). Faraday's law is a bullet precisely aimed at a target while gelatin is a hand grenade. 




10
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=47.0

Quote
Faraday'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=4965.0

Note: 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=47

Lacking an „official“name, let´s for the exercise call it
Formula #2: calculating the amount of dry gelatin, PPM correlated
Application amount:
Quote
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#msg52748

Quote
They 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:
Quote
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:
Quote
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.)

Quote
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.)

Quote
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
Quote
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.
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