Greetings listers,
On April 28 John McLean posted about making 5 gallons of EIS in 8 hrs. using
a modification of my book's layout on pages 29-30, by using a large flat
cathode instead of the rod. He obtained a reading of 25 uS/cm with a TDS meter.
What is missing is the TDS reading after 15- 20 hours as the conductive always
drops.
This work inspired me to verify his protocol, so I made a brew using a flat
cathode of the same size as the anode and spaced at 3". Then I repeated the
experiment by making a run using the book protocol of 1/4" rod cathode. I used
45 volts to shorten the time.
EXPERIMENTAL DATA:
Flat cathode:
Initial DW conductance = 1.1 uS/CM; Cfinal = 20.2 uS; C18 hrs = 18.0 uS/cm
Initial current = 9.8 mA; final current = 61.2 mA.
Silver Ag+ = 11.66 ppm as measured with my spectrophotometer.
Energy input in watt-hrs = 3.798
1/4" rod cathode:
Initial DW conductance - 1.1 uS/cm; Cfinal = 20.1 uS; C17 hrs. = 17.0 uS/cm
Initial current =3.6 mA; final current = 36.2 mA.
Silver Ag+ = 13.2 PPM (Spect.)
Energy input in watt-hrs = 2.796
Based on these two brews the flat cathode is unacceptable.
The problem with using a TDS is the loss of sensitivity at the zero end. I
replaced my TDS with a PWT.
"Ole Bob"
