Thermite consists of aluminum powder together with a metal oxide, usually iron oxide. These reactants usually are mixed with a binder to keep them from separating, though you can mix the materials right before ignition without using a binder. Thermite is stable until it is heated to its ignition temperature, but avoid grinding the ingredients together. You will need:
- 50 g of finely powdered Fe2O3
- 15 g of aluminum powder
If you can't find aluminum powder, you can recover it from the inside of an Etch-a-Sketch. Otherwise, you can blend aluminum foil in a blender or spice mill. Be careful!
Aluminum is toxic. Wear a mask and gloves to avoid inhaling the powder or getting it on your skin. Wash your clothes and any instruments that may have been exposed to the aluminum. Aluminum powder is much more reactive than the solid metal you encounter every day.
Iron oxide as either rust or magnetite will work. If you live near a beach, you can get magnetite by running through the sand with a magnet. Another source of iron oxide is rust (e.g., from an iron skillet).
Once you have the mixture, all you need is a suitable source of heat to ignite it...