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Thermite

Atomicrox

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Anyone here tried some thermite?

I made about 20g with Fe2O3. Burns bright as hell!

I think it wasn't perfect, though. The resulting "blob" had some parts that looked like pure iron but other parts had a lot of what looked like iron oxed left. I think I got the stoichiometry right (about 3 parts Fe2O3 to 1 part Al, by weight) but the scale only had 1g resolution.

Might also be the electrolysis process I'm using to make the oxide. I'm using a small (~1L) container full of water with about half a spoon of NaCl and a 12V computer PSU. The first one I made was with a nail but now I'm using a leftover construction rebar. The first one looked right but this one is looking too whiteish/greenish.
 

MessiTom

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Cool. I always wanted to, never did. Did you use a flare's "wick" to lite it?
 

Atomicrox

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I tried with magnesium ribbon, didn't work. Then I tried with a sparkler, worked like a charm but started too quickly... Next time I'll add some fuse, it's too dangerous with just the sparkler.
 

Hemlock_Mike

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If you are using steel alloy, you likely have
impurities in the oxide.
The stuff will burn the hair off your arm
if you are too close -- Been there:-(
HMike
 

FlutterPie

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Thermite is what they used in 'breaking bad' to get through that door right?
 

crazyspaz

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I made 8 pounds of the stuff a while back, but i used an 8:3 ratio. 8 parts iron oxide, 3 parts aluminum powder. It worked really well...Although i have heard 50/50 mic works as well, so i may try that soon (I have 8 pounds of iron oxide left).

And yea, using magnesium ribbon doesn't work too well....kinda gotta light it then drop the flaming end in, and run away like your life depends on it. I'm hoping the 50/50 mix will burn hotter. the 8:3 couldn't quite get through steel.
 

Sigurthr

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I used to have a lot of fun with thermite! I never had any issue with magnesium ribbon, but I used to pound the ribbon to be very thin so it was more like a foil, it was consumed faster and easier to light this way.

If you're not using pure iron, and if your process produces some of the other iron oxides, you're likely to get a lot of slag and poor quality melt. I found that the particle size for the aluminium matters too. I got the best results from very fine dust, like from using a fine grit abrasive. Just be careful as it is considered an explosion hazard.
 

The Lightning Stalker

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I almost lost an eye to this stuff once when I was a teenager. That was around the same time as the
penny in nitric acid incident. :tsk: So please be careful.

How are you all making the aluminum powder, or are you buying it?
 
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DashApple

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If you are using Fe2O3 then use 50:50 with Al powder. Try your reaction stochiometry again...;) :beer:
If he is using Fe2O3 , then stoichiometry shows ratio of 2.96:1 (3:1) is correct as its Fe2O3 + 2AL = 2Fe + AL2O3 , so the ratio by weight is 3:1 ;)


I've made both Iron oxide thermite and copper oxide thermite along with tin dioxide thermite that gave me a nice amount of tin metal .
 
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grainde

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If he is using Fe2O3 , then stoichiometry shows ratio of 3:1 is correct not 50:50 , So You try your stoichiometry again ;) :p .

Its Fe2O3 + 2AL = 2Fe + AL2O3 , so the ratio by weight is 3:1 .



I've made both Iron oxide thermite and copper oxide thermite .
Haha correct. I even wrote the balanced formula out on a bit of paper and then wrote 50:50...hmm :thinking:

Edit: Its 1 mole to 2 moles. That would mean for eg 30g Fe2O3:

30 g/159.7 gmol-1 = 0.19 moles of Fe2O3
0.19 moles x 2 x 27 gmol-1 = 10.1 g Al

So by mass yes 3:1

Need my coffee its Sunday morning and early here...;)

BTW also depends on the type of Iron oxide used ie (II), or (III), or mix of both (magnetite), as the equations and stochiometries differ for each one.
 
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Atomicrox

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@Hemlock_Mike: I think they're all steel alloys. Not really sure where to get pure iron these days, but I'm open to suggestions.

@FlutterPie: Yep!

I bought the aluminium powder, got the 425 mesh/35um one. Looks like very, very fine stuff!

The electrolysis process most likely generates a lot of different oxides and hydrated oxides. What I did was filter the stuff with coffee filters and then cook it on the stove until it dehydrated completely and left only the reddish/brown stuff. Wiki says at 200ºC it should all be Fe2O3. Sometimes the topmost layer gets blackish, then I grind it and heat up again until it's all red.

If anyone knows a better way to make the oxide I'm willing to try, unless it needs hard to find chemicals.
 

The Lightning Stalker

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@Hemlock_Mike: I think they're all steel alloys. Not really sure where to get pure iron these days, but I'm open to suggestions.
Plain old mild steel should work about the best. Things like old gas pipes, rebar, rods, and
angle. Uncoated nuts and bolts should also work well, but not as well. I take back what I
said earlier about cast. Some types of cast will contain high concentrations of nickel and
chromium. Stay away from tool steel, spring steel, and just about everything else, especially
stainless. It has A LOT of nickel and chromium. Good luck getting stainless to rust anyway.
Car bodies are iffy. Who knows what is in them. Anything that is structurally welded to
something is probably mild steel. Just avoid the weld areas themselves.

You can convert Fe02 to Fe03 by heating it. Oxygen has to get on it while it's hot. If you can
produce an oxidizing flame, that will work the best. A regular profane torch does not do this.
 
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Seoul_lasers

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Anyone here tried some thermite?

I made about 20g with Fe2O3. Burns bright as hell!

I think it wasn't perfect, though. The resulting "blob" had some parts that looked like pure iron but other parts had a lot of what looked like iron oxed left. I think I got the stoichiometry right (about 3 parts Fe2O3 to 1 part Al, by weight) but the scale only had 1g resolution.

Might also be the electrolysis process I'm using to make the oxide. I'm using a small (~1L) container full of water with about half a spoon of NaCl and a 12V computer PSU. The first one I made was with a nail but now I'm using a leftover construction rebar. The first one looked right but this one is looking too whiteish/greenish.

Indeed... and there many kinds of Thermites out there. I have a video of a class of mine doing a CuO + 800 mesh Mg+Al Thermite experiment in Victoria (west shore area) on our back field of a local high school for a special effects class. The kids were impressed. Yes, several classes where there filming it from ~35m away. The concussion was felt at this distance.

CuO + Al or MgAl instead of making a hot jet of flame like the iron based thermite, can actually detonate when even mildly compressed.

I have to put my larger CuO detonation video up to show you how bizarre this binary is...


 

crazyspaz

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Indeed... and there many kinds of Thermites out there. I have a video of a class of mine doing a CuO + 800 mesh Mg+Al Thermite experiment in Victoria (west shore area) on our back field of a local high school for a special effects class. The kids were impressed. Yes, several classes where there filming it from ~35m away. The concussion was felt at this distance.

CuO + Al or MgAl instead of making a hot jet of flame like the iron based thermite, can actually detonate when even mildly compressed.

I have to put my larger CuO detonation video up to show you how bizarre this binary is...

Oooh, I may have to try this...
 

Seoul_lasers

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Actually coming back to making
Metal oxides, it's really not cost effective
and you'll find that the local pottery supply
store has pure Fe2O3 for sale as a glaze colorant.
Same goes with CuO (black copper oxide).

However...

DO NOT make the copper thermite
unless you are outside and have safety
equipment beside you.
I can't stress how incredibly sensitive
this thermite is in fine mesh form.
Also it does detonate with moderate compression.
NEVER make any amount (same goes for any other pyrotechnic) and attempt to store it.
You'll be risking your life if you attempt to
do so.
 




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