I can't believe that this riddle has not yet been solved.
I am no genius, but from the clues given I reckon that Alaskastar is using boron and reacting it with water to create hydrogen by introducing heat via a microwave magnetron.
The reverse process is similar, but using electricity to recharge the boron oxide, strip the oxygen from it and the byproduct is heat.
Read about it on wikipedia
The clues (i can remember) are:
He is using a powdered metal and a dissimilar form of the same - boron is readily available in different isotopes
2 way process (base metal to oxide and back) - Boron does this
Add water and heat under controlled circumstances - boron
The reaction is a bell curve of volatility but controlled by how much water is added - boron.... yawn
Boron is cheap and readily available by the tonne.
Boron in soil grows great tomatos if you don't use too much.
I even printed out this entire thread and sat down to read it, threw it in a cupboard at around page 20... Hehhee
If i'm wrong, It will be something along those lines in the periodic table, ie.... adjacent and I will gladly bow out of this discussion, but Boron seems to fit all the clues.
Alaskastar, let me know mate!
