Cast Thermite

Step 4 Mixing

Now, assuming you either ground your own aluminum or bought some off of the internet, it's time to start mixing our materials.

What we are looking for here is a ratio, (by weight, not volume), of 3 parts iron oxide, 2 parts aluminum, and 2 parts plaster of paris.

I just went by what would fit best in my mixing container. 60 grams of iron oxide, followed by 40 grams of both aluminum and plaster of paris. _{(Divide 60 and 40 grams by 20 and you get the original ratio, 3:2:2.)}

Once you have the right amount, mix the three together thoroughly. The metals tend to sink and 'stick' to the bottom, so make sure to mix it as well as you can until it is one uniform color. In most cases it should look solid gray.

Comments

[Victor Lam]

is it possible to use the pre-ground aluminum oxide used for sand blasting?

[needs_more_to_do]

No it is not possible. Aluminum oxide is not aluminum. To answer your question more thoroughly remember that thermite releases heat by striping the oxygen off of the iron and 'burning' the aluminum. If your aluminum is pre-oxidized this reaction cannot occur.

[Grmgunner]

if we dont purchase our aluminum powder online can we just cut up cans and then break them up in a coffee grinder? and then to get the powder finer do what we did to the iron oxide? like with the ball mill? or will the coffee grinder get the job done fine?

[E3PO]

You should be able to find aluminum powder in any paint store.

[urbosssez]

sorry coffee grinders hate aluminum foil trust me ive tried it atleast 10 times (cuz im too stupid to ever learn that it will never work) all it does is ball up the aluminum foil into small metal spitballs and the powder that it does produce usually gets carried up by the air and smells HORRIBLE if u do try this be sure to wear goggles

[sexpistolsrule666]

you should tear off smaller strips of foil. or get a better grinder. or just order some real alluminum powder...

[Zlwilly]

Maybe you have a bad grinder? Or just bad luck? I've used a coffee grinder successfully many times, the trick to getting past the balled up foil is to continue adding more and more foil strips. As the mass of the total foil increases the grinder... well it "grinds" more efficiently, instead of just throwing the material around the sides. Goggles and a dust mask would probably be a good idea though. I never had any problems with breathing, but the smell I DO remember. ;-)

[Zlwilly]

A coffee grinder and some aluminum foil will work fine, just don't run the grinder until it's too hot to touch or you will burn it up. Foil made this way causes a lot more sparks and light, which I prefer in most cases.

[chriskarr]

What I used to grind my aluminum was foil in a blender with water. Drying the result is a bit difficult, though.