Ok I started playing with NaOH, since I have the time to do it now . .
1st experiment, I've put about 1 pound of Al in a NaOH/Water Solution ..
Put HV discharge electrodes to the top of the bubbler ..
I tried the powder NaOH, but found that it takes a while to react, so I've mix the Drain cleaner and Powder, and the reaction took place immediately ..
I don't know about the amount I used, but not much of the two, maybe there was about 30-40 % of NaOH and the rest was water ...
At first, there was mild bubbling from the bubbler, about 1 big bubble each second (- yeah that's not very scientific -) ..
But the reaction rapidly became violent .. It was bubbling in the bubbler like if I was boiling water ..
I decided to try firing it (- At a distance -) ..
It made explosions without me having to accumulate the gas, water was to about 7 cms from the top of a 2 liters Coke bottle (- the bubbler -) and I saw about 1 meter reddish flames of expanding gas up the bubbler ..
But the bubbler took on fire at every shot, so I had to estinguish it ..
(- Because of the amount of H2, a sustaining invisible flame was burning the bubbler -)
The bubbler didn't last long, maybe 4-5 fires, it was bent because of the heat ..
And the bubbling became heavy, it made a continuous stream of gas, it was no more bubbles ...
So I stopped the experiment there, because the bubbler no longer functionned as intended ..
The Aluminum in the solution wasn't all consumed, in fact, a good amount of it is left ..
I'm thinking about a more sophisticated Bubbler and I will try to sustain a Lawnmower engine with it ..
All in all, I played with this for about 1 hour and didn't have to put more water or Al .
And, pardon me for the lack of Data I will try to take more data on my next attempt with a better setup ..