Step 6: Casting

This is it! The final step!

Take that nice gooey thermite that you worked so hard on and carefully slop it into whatever you are using as a mold. This ice cube tray worked very well as I wanted something small and reusable. Since the shape of the ice cube tray is larger at the 'bottom' I didn't have any trouble removing the cubes.

Keep in mind how the thermite will harden inside an object when you are deciding what you want to use as a mold. Something like a bottleneck vase for flowers would never work unless you planned on breaking the vase off of the cast thermite once it had dried.

Once it has solidified, (it should only take about a half hour to 45 minutes to), pour off the water and remove it from the mold. According to the anarchist cookbook, these will have to dry in the sun for a week, more or less depending on the size of the cast. Alternately you can place them in a oven or dehydrator to dry them much faster, probably in a matter of a few hours, which is the method I use.

Whatever you do, dont put them in your microwave. I doubt they would ignite, but as they are basically chunks of metal, I don't think your microwave would appreciate it. Once again, I'm not liable! Be smart!

As for ignition, thermite requires extremely high temperatures. If it was normal powdered thermite that we were talking about a magnesium sparkler would do the trick, but not for cast thermite. This requires something like the heat from a propane torch, (don't try it, you would have to be far too close to ignite it.) I use something called First Fire Mix. Google it or check back in the near future, as my next instructable will be on making a basic igniter for thermite.

That's it, you're done! If you need any help, check back or comment/pm me, I would be more than happy to help. This is my first instructable, so let me know how I did!

*Edit* For those of you who still need help lighting thermite and other difficult to ignite materials, check this out.

Enjoy your new cast thermite!
<p>How did you grind the aluminum, or can you use aluminum oxide like the kind used for polishing stone?</p>
Very thorough explanation. I'm curious to see with what type of ignition sources you come up with.
i forget the name of it but there's a type of radiator repair stuff that contains powdered aluminum and you can also obtain it from an etch-a-sketch
<p>You got that from breaking bad. lol.</p>
<p>The radiator repair stuff is called &quot;Stop Leak&quot;'</p>
make a castle out of molded tupperware brics, pt army men on it, and light it on fire
That- Is- Brilliant. I always thought it would be a great idea to make thermite legos. Think about the possibilities!
news media: BREAKING NEWS!<br>-Man makes Legos fun for grown men....<br>-New fire hazards in toy stores.
<p>this is cool. I have never made thermite before but I want to try this. </p>
Would it be possible to simply just stick a 10 cm or so length of magnesium ribbon in each cube while they're setting?
thats what I have always done when I have ever used thermite
built in fuse: I like it!
<p>How did this appear in my email feed? I know I'm a fan of thermite, but this is 6-ish years old... and doesn't appear that active currently. So, why feature it in an email blast? </p><p>Unless doing thermite demos is a good halloween treat (umm, really? really?) then this seems a bit inappropriate to me.</p>
I wonder if a mixture of potassium permanganate and glycerine would ignite it, if you could figure out how to mix them from a distance on the thermite that is. <br>
<p>That's how I light my thermite. The reaction is delayed by several seconds, so you have time to move to safety.</p>
<p>Hi guys i have a question about this iron oxide i understand its rust but all the videos i've watched about making iron oxide its a liquid with a battry charger and old nail etc. Im sure youve seen them but if i were to scrape rust off let's say an old bike then used a ball mill,mortar pestal,etc would that still be iron oxide or something else? thanks</p>
<p>Use old prescription, film canisters filled 2/3 then you could thread fuse thru the cap and into the mix before dry... Just a thought.</p>
<p>Hi Zlwilly &amp; The Instructables Community,</p><p>Just a thought on possibly problamatic ignition.</p><p>I have heard of people using sparklers to ignite the powdered mixture, but obviously this cannot work here. </p><p>So I got thinking, why be constrained by this?</p><p>I thought that while the mixture is setting why no put a short cut length of drinking straw into the top of the mixture (possibly plugged to stop water equalisation). Once set you then have a convienent hole to place either a short length or a full sparkler for a timed fuse.</p><p>Just a thought as I said, but I would love to hear if someone gave it a go!</p><p>Regards, </p><p>The Apple Sauce Man</p>
is it possible to use the pre-ground aluminum oxide used for sand blasting?
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.
Aluminum metal (Even in alloy) forms an oxide layer almost instantly after having the existing oxide layer removed and then being exposed to oxygen. I don't remember the exact time, but its on the order of nanoseconds.
shouldn't the iron oxide be reddish brown?
Fe(III) Oxide is usually a brighter &quot;brick&quot; red
Hey not sure if anyone else has mentioned this but you'll have an easier time mixing if you add the powder to the water. It will also give you a few extra minutes of play time before it starts to set. Once it's mixed add a pinch of table salt and it will halve the setting time. This only works with plaster of Paris, with harder plasters like dental ones it slows the reaction. Don't ask me why I don't know. Not sure if the salt would affect the burn though.
would a rock tumbler work as well?
I think I have an experiment to do using arrows =D
a better way to get iron oxide is by the electrolosis of a salt water solution with some iron rods. Not graphite. Then filter the muck and let it dry. Grind it up in a pestle and mortar and there powdered iron oxide.
That is a 'better' way to get iron oxide, if you're looking for efficiency from cost/time/end-product mass Vs. beginning mass. There is one thing that you did not consider, though, and that is the fact that when you make iron oxide via electrolysis you do not have an end product of Fe2O3 which is the best iron oxide to use for thermite mixtures.
Whats wrong with Fe3O4? it has more oxygen, shouldn't that let the thermite burn better?
I dont believe you can make Fe3O4
i&nbsp; didnt think that you could make h2o2 but i was worng...
Can someone help me out here? <br> <br>http://www.instructables.com/answers/How-to-i-turn-a-computer-power-supply-into-a-iron-/ <br> <br>
I did through <a rel="nofollow" href="http://antique-engines.com/electrol-details.asp">water electrolysis</a>. When you get to the drying part, evaporate it as heating it(in a propane grill) turns most of it back into Fe2O3.<br/><br/>(pic: red is the grilled, black is evaporated)<br/>
oh kk nvm<br />
nice icon
It would be awesome if you could freeze an ignitor into it, like a press button that when you throw it...it burns.
Can someone help me out here? <br> <br>http://www.instructables.com/answers/How-to-i-turn-a-computer-power-supply-into-a-iron-/ <br> <br>
Thanks for the Instructable. I'm going to second another commenter and recommend 2% Dextrin as the binder instead of plaster (bake cornstarch a.k.a. cornflour in the oven for 2 hours at 200C, mixing every 30 mins). Lighting it with KMnO4 and glycerol is generally much safer than a propane torch or flash powder mix too (at least gives some delay). As a word of caution, making thermite is probably classed an manufacturing pyrotechnics and illegal in most places. Unless you have experience with pyrotechnics, safety practices, solid chemistry knowledge, etc. don't mess with it. Also if you add chlorate (as one poster suggested), make sure you don't use First Fire Mix as it contains sulfur which can degrade to trace amounts of sulfuric acid and cause spontaneous combustion.
Forgot to add that when the block is x'ed out with 1/4&quot; deep grooves just sand it flush and go again. Also check your alloy, just because it's Al doesn't mean it's pure.
I like to place my iron oxide in a small coffee can with some old BB's and ball bearings and give it a good shake for a few minutes. As for the aluminum I have a 6x6 block from a local hardware store that I cut grooves into with a hacksaw. Light pressure will get close to a fine powder.
Where in the anarchist's cookbook does it talk about thermite?
The part that also says that that isn't something that should be involved with this site.
The best way I found to do this is using a metal pipe about 4 or 5 in. wide and how ever long you want I'd keep it around 3 feet long. Stuffing the pipe with steel wool, lighting it (duh), and having a fan blow through the pipe from one end. it works great. ;)
You can also light the steel wool with a 9V battery.
i need to grind up aluminum is there another way besides a coffee grinder
Small rock tumbler with BB's works great for pieces of Aluminum Foil.
aluminum seems to be a problem for a lot of people i have found that the best quality of aluminum powder can be found inside of an Etch-a-Sketch. the grey powder in side of it is as fine a powder as it comes you can even use the beads to give a good combination of coolness and functionality!
...again, a rock tumbler with BB and pieces of Aluminum Foil WORKS AWESOME. In my opinion buying or even salvaging an etch-a-sketch for the aluminum powder is:<br><br>a) More work than it's worth.<br>b) Waste of an etch-a-sketch (they're not hard to fix)
I just took a file and scraped some pop tabs across it.

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Bio: What's to say? I have a deep passion for all things electrical and mechanical, and the more of it I can get my hands ... More »
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