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ChemTechLabs

Sat Feb 11 2006, 05:06AM

Registered Member #98 Joined: Thu Feb 09 2006, 05:53PM
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Posts: 14

If anyone has ever whipped up a batch of Thermite that has succesfully worked, please help me!

. I've tried different ratios of the Iron Oxide to the Aluminum Powder but it hasn't worked for me yet. Does anyone know a ratio that would work well? And what about methods of ignition? i've tried Magnesium strips and that doesn't seem to be very effective either. it could be that its too small of an amount that it wont light, other than that i'm stumped.

...

Sat Feb 11 2006, 05:31AM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

how did I know the first thread in chemistry would be about thermite

If you wanted to do the math you would take the reaction 2Al + Fe2O3 => 2Fe + Al2O3, and then use the molar masses of Al and Fe2O3 (27g/mol and 160g/mol respectively) to get a ratio of 3 parts Fe to 1 part Al (by weight) for a stoichiometric reaction.

As far as the real life reaction, you must be sure that the aluminum and rust you are using are very finely ground (otherwise the reaction will not proceed as quickly as you would like), and that they are thoroughly mixed (so you have the right mixture throughout the burn, not a to much aluminum then too much rust).

One way to insure an even mix is to mix the two in solution of some volatile substance (like methanol or acetone) and let it dry. This insures that you get a good even mix of aluminum and rust.

Good luck and be safe!

Mike

Sat Feb 11 2006, 07:32AM

Registered Member #58 Joined: Thu Feb 09 2006, 05:40AM
Location: Tri-Cities, Washington, US
Posts: 317

Well, I would suggest buying higher grade Aluminum , pyro aluminum

, sells very high grade stuff.
Also on your synthesis, the rust should be approximately 2.888 the mass of the aluminium. If you don't want to buy from pyro aluminum, you can get powder from paint shops and auto shops since it is used in paints. Iron Oxide is also used as a cement color, so it may be found at a hardware store / industrial.

Have fun!

Edit: And on the point of starting it:
For Magnesium Strip. Place the strip alongside the thermite. A potentially safer method if materials are available is to place ground potassium permanganate in a small crater in the thermite and pour glycerine on top.

It is also possible to use certain types of sparkler fireworks and probably magnesium road flares. The magnesium fire starters used for camping will ignite thermite. A small (1cm3) crater should be dug in the mixture and filled with the filings scraped away from the magnesium block.

An alternative method of igniting thermite is to use the head of an ordinary match. The simplist way to do this is to place the head of the match into the thermite, and then light the other end of the match. When it burns down to the bottom (the head), the chemical ignitor of the match will light and get hot enough, if only for a second, to ignite the thermite reaction.

I would suggest the match method first, since it is the easiest, how ever it may just be a myth. More Info at Wiki Synthesis:

craigsarea

Sat Feb 11 2006, 10:34AM

Registered Member #130 Joined: Fri Feb 10 2006, 08:12PM
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Posts: 15

wrote ...
how did I know the first thread in chemistry would be about thermite

It's not chemistry without thermite

.

I've got some thermite reactions on my website:

I used 250/D grade aluminium powder. For the iron oxide I tried both homemade and LR grade. The homemade iron oxide was made by electrolysis and gave quite good results.

The best results I got though were when I used LR grade iron oxide. I used 300g of iron oxide and 100g of aluminium powder. The thermite was mixed well and packed tightly into a food can. Once the reaction started it was very fast and very big (loads of heat). At the end there was blobs of molten iron on the floor. The food can had melted almost instantly. The reaction was so fast and fierce I didn't manage to start the video in time to capture it

.

I use a high voltage arc from a 4-MOT stack to ignite my thermite. Although having to setup the 4-MOT stack is real pain so I would recommend the magnesium instead.

If you're making the iron oxide yourself then its colour should be red. Are you making the iron oxide yourself?

Self Defenestrate

Sat Feb 11 2006, 01:35PM

Registered Member #87 Joined: Thu Feb 09 2006, 01:36PM
Location: San Jose
Posts: 191

I've gotten a few good thermite reactions, I used a well dipped into the mix filled with shreds of Mg. Turned out my Fe2O3 was bad the first time around, so I bought some red brick pigment from a local hardware store. The Al came from an old Etch-A-Sketch. Fun stuff, but I ran out of aluminum in about two days

Hazmatt_(The Underdog)

Sun Feb 12 2006, 02:55AM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

I experimented a lot with Thermite before I had access to chemiclas, credit cards, or a car, and I can say, it really forces a person to be creative.

The absolute hardest part was getting the Al to burn. Why? Well because the only Al I had access to was 6061. It's alloyed to such an extent that even with my cutting torch, tested recently, It does not catch!

So what can you do?

Well, its pretty simple actually. Like everyone else is saying, you can get the Mg firestarters, that helps a lot. But here's where it gets a bit tricky.

Say you don't have good consistantly ground up Al, like my case. After you sand it with a sander, hopefully wearing a lot of protection and that it doesn't ignite in the air, you get the dust of all sizes, mix that with your home made rust, and you've got Thermite, but doesn't ignite. That was my case.

Well, after getting a scale from a pawn shop, and improving my rust process, neutralizing Ferric Chloride, I still had problems. So much of my time was spend very carefully grinding Mg bars down on the drill press with a drum sander. The Mg blows away really easy, so I made a dust box and it worked really well.

Next problem was the fact, MgO extinguishes Thermite!

So you make a 'booster'. Mg and Fe2O3 just like Thermite. This is pretty nasty stuff and really helps to 'boost' the Thermite reaction.

I would have used chlorates, but how does a 16yr old get chlorates without the parents knowing, this is difficult.

So have fun, but be very careful with the dust! Wear gloves because Mg gets under the skin and causes blisters that don't go away until the Mg is removed!
Also protect yourself from the dust getting in your eyes, lungs, hair. And grind very slowly so the heat doesn't build up.

muciek man

Mon Feb 13 2006, 11:52PM

Registered Member #163 Joined: Mon Feb 13 2006, 01:55PM
Location: caledonia ohio
Posts: 22

watch that heat build up mg has been known to explode durning machining due to heat buildup same as with mag wheels they would catch a curb,spark instant car fire you probably should use a file instead of a sanding drum eaiser to colect shavings and safer too

better safe then sorry

Hazmatt_(The Underdog)

Tue Feb 14 2006, 06:14AM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

filing is very difficult! If you've ever done it you know that your losses are high because the slightest movement of air blows the filings around.

Like I said, if your careful, and I was, and use a dust box protection and are aware of any heat, its not a problem. I don't remember my Mg bar ever getting hot during sanding either. I was using the slowest spindle speed as well.

A note for you guys if you want to use a dust collection box. Don't think under any circumstances that using a shop vac will improve your collection yield! This is an ABSOLUTE mistake! The vacuum is cooled by passing the exhausted air through the motor. If you try to collect Mg with a vacuum you will EXPLODE!.

Be safe okay!

ChemTechLabs

Wed Feb 15 2006, 01:27AM

Registered Member #98 Joined: Thu Feb 09 2006, 05:53PM
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Posts: 14

Thanks very much guys, i'll use your tips and hopefully this weekend be succesful!

IamSmooth

Sat Feb 18 2006, 07:21PM

Registered Member #190 Joined: Fri Feb 17 2006, 12:00AM
Location:
Posts: 1567

My first reply on the new board is about Thermite?

I did this when I was in high school. I started it as already stated above some of the others: I used a magnesium strip to set it off. I also used a crude smoke powder made from potassium nitrate and sugar with a waterproof fuse. You just need something very hot.

While having correct stoch ratios are good, they are not necessary to have a successful reaction. The only purpose to having correct ratios here would be to have a complete reaction, using up all of the reactants. If the ratios are not correct you will end up with either unused Al or rust.

Make sure that you do this outside as I melted a large hole in my street and some neighbors called the firedepartment. I was long gone. Ah, highschool.

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