Just wiki 'thermite'
Stoichiometry is simply matching the ratio of one reagent to another,by molecular/atomic weights.
In the case of red iron oxide (there are 16 different oxides of iron, and a couple of different hydroxides), its simply rust. Fe2O3. 196g/mol. Aluminium has an atomic weight of 26g/mol, 26.9, to the nearest one digit. So you want 2 moles of aluminium powder per mole of Fe2O3, to abstract all of the iron, forming aluminium oxide and iron, once ignited.
Its hard to ignite, very, very hard. Blowtorching it for quite some time will do it, but the best way is to stick a strip of magnesium ribbon into the thermite, and light the Mg with a blowtorch. Mg burns hot enough to ignite thermite. Alternatively, one could make a variant of thermite that ignites easier, thermate, made by adding a little sulfur (obtainable from many pet stores, for some reason its sold for adding to the drinking water of various animals)
http://en.wikipedia.org/wiki/Thermate Thermate has a lower ignition temperature than thermite, and burns even hotter. Shit will cut through the armor of a tank.
Thermite equation-2Al+Fe2O3 (ignition)=2Al2O3+2Fe.
The stoich is pretty damn simple for thermite. Be aware though, that iron (III) oxide STAINS like a complete fucking bugger. Line your scales with a sheet of tinfoil, or it will work its way into any minute cracks, and never, ever come out. For thermite, one wants a fine mesh powder for the aluminium. The two components should be mixed intimately. Its very stable, won't explode and can be stored longterm.
