How To: Make the World's Hottest Burning Man-Made Substance: Thermite

Make the World's Hottest Burning Man-Made Substance: Thermite

I feel like doing a bit of chemistry today, how about you? To my knowledge, thermite is the hottest burning man-made substance. Thermite is a pyrotechnic composition of a metal powder and a metal oxide that produces an exothermic oxidation-reduction reaction known as a thermitereaction.

Fe2O3 + 2 Al -> 2 Fe + Al2O3

Basically, a high temperature burning metal like iron oxide (rust) mixed with an easier to ignite, oxidizing metal will produce incredibly high amounts of heat in a small area for a short amount of time. Thermite is so hot and powerful, that it can even burn straight through asphalt. This is fun for some homemade fireworks, but beware, it's against the law to make incendiary mixtures like this and ignite them.


  • A 9v battery -OR- iron oxide powder bought at a paint supply store
  • Some wire
  • NaCl (table salt)
  • Aluminum foil or powder
  • A jar
  • A metal file
  • Magnesium strips to ignite the thermite. You can also use sparklers, as most of them contain magnesium

Step 1: Collect Some Rust

To collect some rust, we can either go to the paint supply store to get it ourselves, or make it at home. Buying it is far easier and more convenient. Paint stores often sell iron oxide power as a color additive for paint. But if that isn't an option, here's how to make it:

  1. Fill a jar with water.
  2. Add a tablespoon of salt to the water.
  3. Wrap separate wires around the positive and negative ends of the 9v battery.
  4. Stick both wires in the water and see which one makes more bubbles.
  5. Take the wire that makes more bubbles and wrap the exposed part to something metal, preferably iron, like a nail, and sink it in the water while removing the other wire.
  6. Wait a few days for rust to build up, and scrape it off into a bowl with a metal file. Repeat to your heart's desire.

Step 2: Aluminum

Using aluminum in thermite is great because it has a low ignition point, but burns at a high temperature. This allows for very hot thermite. To get aluminum, you can also buy this from a paint or hardware store, but you might not want to buy them at the same time, in fear of the employees suspecting what you are up to.

You can actually grind or cut up plain old aluminum foil if you can't get any power. Try to get the chunks as small as you can.

Step 3: Mix It Up & Burn

You should have a visual 50-50 mixture of rust and aluminum. Meaning they look like the same amount, but do not weigh the same.

Using a very long strand of magnesium ribbon, put it in a pile of thermite, ignite it, and run away. You can use a sparkler, too.


  • Be *very* careful! You could kill yourself if the thermite ignites with you too close.

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[by Mass] 2.96 parts of Iron(III) oxide to 1 part Aluminium (3:1 by mass is good enough)
[by Volume] 1.52 parts Iron(III)Oxide to 1 part Aluminium

I'd use the mass ratio as the fineness of the powder will affect it's density.

Fe2O3 + 2Al > 2Fe + Al2O3
Al - 26.98 grams/mol
Iron(III) oxide - 159.69 grams/mol
159.69 grams of Iron(III) oxide reacts with 53.96 grams of Aluminium
[by Mass] 2.96 parts of Iron(III) oxide to 1 part Aluminium (3:1 by mass is good enough)
Aluminium Density is 2.7 g/cm3
Iron(III) oxide Density is 5.242 g/cm3
7.992g/5.242 = 1.52461cm^3
2.7g/2.7 = 1cm^3
[by Volume] 1.52 parts Iron(III)Oxide to 1 part Aluminium

Yeah.. What he said.

Also, I cannot stress enough the fact that safety with this substance should be of the utmost priority. That sh*t melts through iron like it's butter. Temp high is 2.5k degrees. Needless to say if your list of possible applications start and stop with burning through someone's car hood or melting the neighbour's cat, you should not be using this compound.

heh, its sooo dangerous. i lit some in a thick metal container with explosives underneath (wayyy out in a field). it exploded in a volcano like way, totally amazing.


@Christopher That sounds epic. I would love to try this but I feel like I'm breaking the law just looking at this page. Did you get any footage?

so i mixed my thermite 1 tsp powdered aluminum to 2 tsp iron oxide and mixed. i took about a quarter of a teaspoon on a log and built small logs and sticks all on top of it, threaded a strip of magnesium in and wow do i know my new favorite firestarter. not entirely sure how safe this was inside my house but hey it worked and its super easy

Okay some misinformation here, let's try to hit them all shall we? 1) Thermite is not illegal to mix or ignite as long as you aren't doing anything unlawful with it. 2)Thermite should NEVER explode. The only time it has explosive potential is when you substitute Iron oxide for cupric oxide, and at that point it becomes more dangerous than flash powder. 3) you don't mix thermite by volume. That's not to say you can't it's just what I was told when I got into pyro stuff, I'm just passing it along. 4) Thermite does not burn at 2.5k degrees F , It burns at ~2300 degrees Celsius or ~4000 degrees Fahrenheit , Those sparks you see are an exothermic reaction burning the aluminum and the oxide and THROWING HOT IRON, While it almost definitely won't kill you it absolutely will hurt. Experience.

Remember Thermite itself is not illegal, just don't be an idiot with it.

Dicyanoacetylene is the hottest burning substance

Thermite burns at a miniscule 4,000 deg F.
Magnesium burns at 5,610 deg F.
DiCyanoAcetelyne burns at 9,010 deg F and is the hottest reaction achievable with current chemicals.

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