What going on with my mini electrolysis machine?

[GreenElectron]

I built an small electrolysis setup (separate hydrogen and oxygen) using two thick plastic toothpick bottles about 3.5 inches in height and 1.25 in diameter. I connected the the two bottles using a 2 inch length of of 1.25 pvc and epoxied the joints. poured in distilled water with 10% solution of NaOH. sealed in two stainless steel dowel holders as electrodes on the covers. I had fittings on each bottle cover with plastic tubes that collect the hydrogen and oxygen products separately. The oxygen part was just released to the environment. The hydrogen part went through a small bubbler made out of the same tooth pick bottle filled with 50% distilled water. The output of the bubbler went to a 6 inch homemade flame arrestor filled with stainless steel wool and the output of this thing went to a syringe needle like chris's early electrolysis machine. Fired up the setup with a 12 volt battery. Got some good bubbles in all bottles. However I could not build enough pressure for the hydrogen to get to the needle part because after a minute I had to turn off the unit because the water in the oxygen (anode) part was overfilling and pushing the cover off and leaking electrolyte. The hydrogen (cathode) part has the water level pushed down to the anode bottle part (more gaseous space I think). To relieve and equalize the pressure I disconnected the plastic tube to the hydrogen bottle part and water level becomes equal on both bottles. Never seen this problem with I did it with a combined anode and cathode plate in a single container. My question is, if anyone can help, how do I keep the water from rising in the anode part so that it doesnt overflow? Tried temporarily sealing the oxygen output fitting and the water rise will slow down for a moment but eventually overpowers the cover and starts to leak out. There is nothing blocking the movement of hydrogen to to bubbler and the flame arrestor because I can blow air into the tube leading to the bubbler , arrestor and needle (I place the needle in a glass of water). Very little effort is needed is to see bubbles coming out of the needle. Any explanation or help is appreciated.

[Bob Boyce]

[GreenElectron]

Thanks Bob for your thoughts on this. I was pretty much thinking about the back pressure thing too but I also thought there were other factors involved. Anyway I'll work on the oxygen bubbler advice you gave.