Thermite is a mixture of a metal powder and a metal oxide that produces an extremely hot burning exothermic reaction when heated to ignition temperature. This article will instruct you on how to make several different forms of thermite, as well as how to bind the mixtures into more useful solid or semi-solid consistencies.
First, a bit of safety info. Large quantities of thermite can be extremely dangerous, as the compound burns at thousands of degrees Celsius and is liable to throw bits of molten metal all over the place. No more than half a kilo of thermite should be necessary for completing almost any objectives you may have for it, as this amount is enough to melt clean through the engine block of a car.
No matter what, always use safety precautions when handling thermite.
With that said, common formulas for thermite are as follows:
1) Aluminum thermite ideally consists of 7.5 parts iron(III) oxide (otherwise known as rust) and 2.5 parts aluminum powder by weight. Simply mix these two components together and you have thermite. For ease of ignition, ingredients should be ground to a very fine consistency similar to granulated sugar. This mixture burns at over 2500°C.
Obtaining the aluminum for this reaction is as simple as sanding the labels off a six pack and grinding them into dust. If you don’t have a power sander for this then a nail file will work just as well, albeit at a much slower pace. Aluminum powder can also be found inside a common Etch-a-Sketch, or simply bought online in bulk. Amateur fingerprint kits also usually come with a small jar of aluminum powder, although I’m not sure about the purity.
The iron(III) oxide may be a bit trickier. Like aluminum, it can also be purchased in bulk from online retailers, or sometimes in paint shops. But if you don’t have the resources for this and/or you are a cheapass, you can make your own with a 9 volt battery, a copper wire, some steel wool or a nail, and a bucket of salt water. Get creative. Instructions can be found on google.
This mixture is notoriously difficult to ignite, but I’ll get more into that later.
2) Magnesium thermite is very similar to the previous formula, only this time you’re using 7 parts of iron(III) oxide and 3.2 parts magnesium. Magnesium thermite has a much lower ignition temperature than aluminum thermite. In addition, it also burns slightly hotter, more quickly, and with better precision.
One of the main drawbacks for this mixture though is obtaining the magnesium. Again, it can be bought in bulk online or in machine shops for use in welding, but it’s more expensive than aluminum. If you wanna get cheap, you can buy solid sticks of magnesium in the form of fire starter kits and grind them into powder yourself.
3) Gypsum plaster (aka plaster of Paris, or hemihydrate calcium sulfate) and aluminum, though not exactly thermite per se, deserves mention in this article due to it’s unique properties as well as the fact that gypsum plaster is probably one of the easiest ingredients to obtain in this guide. You can buy it at Lowe’s. By weight, the best mixture is approximately 2.7 parts gypsum plaster to 1 part aluminum powder and it will burn even hotter than traditional thermite. It is, however, much harder to ignite.
If left in open air, this mixture will begin drying within 15 minutes and become mostly set within an hour. However, if stored in an air tight container, it won’t dry right away. This means that you can carry it with you and apply it to a surface just like normal plaster. The effectiveness is not as potent as other forms of thermite, but it can make for some very creative applications.
You can also use anhydrous calcium sulfate for this mixture, but the result will be in a simple powder form just like normal thermite.
There are many other forms of thermite using various reactive metals/metal oxides, but most of them are either more difficult to create, less effective, or used only in more specialized situations, so I won’t bother getting into them.
Ignition:
Igniting a thermite reaction can be challenging. The most common method used by amateurs is sticking a simple child’s sparkler into the mixture and lighting it. The magnesium in the sparkler can burn hot enough to ignite the thermite, but given environmental or other factors, this may not always work. A magnesium ribbon or professional grade hot burning fuse will usually do the trick, but this is not a guarantee either.
In order to lower the required ignition temperature, you might want to mix in small quantities of other components, such as sulfur and/or nitrate salts such as potassium nitrate or barium nitrate. Potassium nitrate can be found in 100% purity in many brands of stump remover (such as Spectracide brand stump remover). Barium nitrate is more effective, but harder to obtain. I’ve never used it personally. It’s found in some insecticides.
Mixtures that contain these extra materials are generally known as thermate. Thermate burns hotter than thermite and is more focused and precise. It also creates more flames and releases more gas. Military grade thermate uses a mixture containing 68.7% thermite, 29.0% barium nitrate, 2.0% sulfur and 0.3% of a binder material. Like I said though, I’ve never used barium nitrate, but I have tried mixtures of 80% thermite, 17% potassium nitrate, and 3% sulfur. I don’t know if these are the exact, most ideal stoichiometric measurements, but they seem to have a good enough effectiveness. You can experiment and research a bit on your own to find more effective ratios, but be very careful as higher concentrations of these extra components can be explosive.
Binding thermite:
Thermite or thermate can be bound into other materials to give it a more uniform consistency to increase it’s range of application. For example, a mixture of about 4 parts thermite to 1 part Plasticine can create a moldable block of thermite that can be shaped and carried around in a semi-solid form rather than as a powder that can be spilled or scattered. Plasticine is more effective as a binder than regular ceramic clay because it won’t air dry, and is flammable.
However, if you actually want a mixture that will dry out in open air to create a solid substance, Air-Dry Clay from Crayola will dry faster than normal clay, but is also flammable.
And that’s thermite for you. Have fun.
By Anonymous
