The eight electrolyzer plates are about 0.8mm thick 160mm x 200 mm stainless steel (304 grade). A 10mm gas vent hole is drilled in each plate. The electrolyte level is always about 25mm below the gas vent hole. There are 3mm diameter liquid level equalization holes drilled in the bottom corner of each plate (not shown) in such a way that adjacent plates have holes in opposite corners. Staggering and using small holes minimizes any efficiency loss due to current leakage between cells, but makes electrolyte refilling and level equalization significantly easier. The two end plates have a small SS piece welded for electrical contact. After taking the picture the plates were sanded with an orbital sander to expose clear metal and then cross-hatch pattern was “engraved” on the plates with a rough file attached to a wooden block. This is to increase the active surface area of the plates and seems necessary for ultra high efficiency. Other methods to increase plate area exist as well.
Nine spacers were cut out of 3mm thick soft and transparent PVC sheet with a knife. The wall thickness is 12mm. The PVC sheet is originally designed for door material for large room-size refrigerators. The small square PVC blocks were meant to keep proper distance between SS plate centers, but they turned out to be unnecessary and were not used.
The end plates were cut out of 12mm thick PVC plate. The size of the plates was 200mm x 240mm. Eight 8mm holes were drilled for M8 size stainless steel through-bolts. A ¼” pipe thread was tapped in a 11.8mm gas vent hole. A valve and gas hose connector was epoxy glued to the ¼” tapped hole in both plates. Other thread sealants may not be compatible with the electrolyte so it’s best to use epoxy or teflon tape. The valve was lined up with gas vent hole in SS plates. NOTE: When the electrolyzer stack is tightened up the PVC end plates tend to bend and bulge. Some form of metallic bracing should be used to prevent bending or the end plates made out of thick stainless steel plate.