I built a wfc, bought a dc gated pulse generator ala dave lawton, added distilled water and got pretty much nothing. I next bought a dimmer switch (poor boy's variac) hooked to a fwbr with floating ground and got bubbles and heat. Burned out 2 dimmer switches and for giggles hooked up 12 volts dc straight to the wfc wired parallel and got not as much bubbles but less heat. Water bath is about 2 degrees F above ambient.
Construction:
7 - 5/16 inch 316L allthread rod cut to length
7 - 1/2 inch od 0.035 wall T304 pipe 100 mm approx 4 inches in length
42 - zip ties superglued 120 degrees as spacers gap approx 1.5 mm
hardware ss nuts, washers and hose clamps for electrical connections
hoseclamps attached approx 0.25 mm from bottom
silver plated copper wire seems to hold up in the water bath wired as per figure 2 in the patent
With tap water it seems no problem producing bubbles and steam at 12 vdc unrectified. Puzzled and surprised...