Sciencemadness Discussion Board - Thermite using 'blender grade' Al powder, is it possible ?

Thermite using 'blender grade' Al powder, is it possible ?

Pyro_cat - 5-5-2018 at 12:49

I was thinking maybe if real fine Al powder was used at the ignition starting point once the reaction got going it would continue even with more course Al powder in the mix under it. I would think the aluminum would be vaporizing after initial ignition so particle size would be less important.

JJay - 5-5-2018 at 13:05

I made a thermite-like composition with aluminum powder I made in a coffee grinder and copper (ii) chloride; it sustained a highly exothermic reaction. It was necessary to grind the aluminum to a fine powder; during my successful attempt, I burned out the coffee grinder grinding the aluminum. Larger particles of aluminum (the size of a period on a newspaper) did not react unless heat was continuously applied. If I try making my own aluminum powder again, I'm going to try running it through screens to get a better idea of the particle size.

PirateDocBrown - 6-5-2018 at 11:18

My experience so far is that powder that can pass a 200 screen is fine enough.

I am currently developing a ball mill to make aluminum fine enough for thermite, or for use as a reductant. I hate using wads of foil.

Bert - 6-5-2018 at 19:57

It is possible to blend various sizes of Al fuel particles in such mixtures to achieve a desired reaction rate- A little bit of German blackhead Al or even some nano particle Al may be reactive enough to bring coarser grades up to temperature.

Also, depending on your purpose for using a goldschmidt reaction, you may choose to use more than one metal oxide for the oxidizer. Or adjuncts such as Sulfur.

JJay - 7-5-2018 at 11:21

First, buy your own blender, don't try to use your wife/mother/girlfriend's or you will be sorry.

Quote:

I am pretty sure it is possible to create thermite with aluminum powder made in a blender

Use a blender jar about 2/3 full of light mineral oil or a similarly viscous and non reactive fluid. Put your shredded Aluminum foil you want to powder in, run blender. Add more foil until you have something still pourable, but like a pancake batter. Keep running the blender, you may need to let it rest and cool for a while then return and run it some more.

The blades are keeping the oil turbulent. The oil is tearing apart the foil, also preventing the Aluminum from aglomerating into little foil balls.

When a sample removed and solvent washed is fine enough, filter what oil you can out of the slurry, then do a couple of solvent washes to remove the oil.

[Edited on 5-8-2018 by Bert]

(Crap! Sorry JJay)

[Edited on 5-8-2018 by Bert]

Pyro_cat - 8-5-2018 at 13:02

Aluminum powder. How about enclosing an angle grinder in a closed environment of inert gas, helium easy to find, and rig an aluminum rod to press against the grinding wheel.

Edit: The grinder could be rigged so the sparking and cooling part is outside the enclosure, glue tape caulk it into a hole in the side of the enclosure.

[Edited on 8-5-2018 by Pyro_cat]

Pyro_cat - 21-7-2018 at 21:25

I wonder if crazy glue is strong enough that I could use it to attach razor blades to the blender blades and maybe not get the aglomerating into little balls like mentioned above. That seems to happen from the blades not being sharp enough and just beating them instead of cutting them. I know a sharpened blade makes a huge difference on a mulching mower. Next step try the Dremmel to sharpen the blender blades and finally make some of the infamous thermite.

And to make rust a little quicker bleach and vinegar right ?

Abromination - 21-7-2018 at 21:51

Don't mix bleach and vinegar!

Abromination - 21-7-2018 at 22:03

Don't mix bleach and vinegar!

JJay - 21-7-2018 at 22:55

Quote: Originally posted by JJay

First, buy your own blender, don't try to use your wife/mother/girlfriend's or you will be sorry.

Quote:

I am pretty sure it is possible to create thermite with aluminum powder made in a blender

Wow, that is a super-cool post.

unionised - 22-7-2018 at 05:47

When the process was discovered in 1893 it is unlikely that they had access to anything much better than a coffee grinder to make Al powder.

Pyro_cat - 22-7-2018 at 18:05

Quote: Originally posted by Abromination

Don't mix bleach and vinegar!

I learned that from the chemistry section of the 1977 World Book encyclopedias and tried it as a kid and I survived. It did rust stuff real quick. It also said stuff about ants and junipers and formic acid. Back before the internet if you wanted to know about energetic materials the trick was to read the even older encyclopedias.

Pyro_cat - 22-7-2018 at 18:46

Quote: Originally posted by JJay

Use a blender jar about 2/3 full of light mineral oil or a similarly viscous and non reactive fluid. Put your shredded Aluminum foil you want to powder in, run blender.

I just tried it with water not caring if I oxidized it and did not get a better result. I was hoping for gray water.

OneEyedPyro - 22-7-2018 at 19:48

I know you're asking about a blender but if you can afford a blender, you can also afford a cheap rock tumbler to use as a ball mill.

Also, foil is often hard to mill down due to its tendency to form into little balls.
I use a block of Al and use a drill bit to make shavings, they mill down much faster and make a higher quality powder with less oxide in my experience.

JJay - 22-7-2018 at 21:26

Quote: Originally posted by Pyro_cat

Quote: Originally posted by JJay

Use a blender jar about 2/3 full of light mineral oil or a similarly viscous and non reactive fluid. Put your shredded Aluminum foil you want to powder in, run blender.

I just tried it with water not caring if I oxidized it and did not get a better result. I was hoping for gray water.

That was actually Bert's post, but water has low viscosity. I'm not sure why he specified a viscous fluid.

Ball Milling Theory and Practice for the Amateur Pyrotechnician

CouchHatter - 23-7-2018 at 19:05

Bert, your method does sound impressive in its resourcefulness. Those hours and hours I've used a cheap blender...

For a larger scope of application, however, I recommend a real ball mill. I don't make money from the sales of this book, I just think it's really valuable information. I'm not interested in fireworks or thermite (yet!), but I have plenty of other uses for grinding things into powder. A ball mill is a semi-luxurious thing, and this book tells you how to make a very efficient, customizable one. Also some great background on why they work and how they work best. It's been worth every penny to me.

Pyro_cat - 19-7-2019 at 19:41

Been a year but I am finally doing this project. So many videos I want to see this in real life. The lava in Hawaii, that in real life was scary. Video does it no justice.

Lots of screening and sharpening the blades on the blender really helps, I think I am good to go with the aluminum. So focused on that didn't realize a quantity of rust is not the easiest thing to make if you are to cheap to buy bags and bags of steel wool. Just waiting on those finishing nails under water in the casserole dish.

I am going to go with a strobe cup to try and initiate it. The brightness of those things tells me that is the hottest thing I am going to find.

Microtek - 21-7-2019 at 04:33

For the iron oxide, consider going to a paint store and buying it. It is often used as a red (Fe2O3) or black (Fe3O4) pigment, and usually sold pure.

Pyro_cat - 21-7-2019 at 22:14

Quote: Originally posted by Microtek

For the iron oxide, consider going to a paint store and buying it. It is often used as a red (Fe2O3) or black (Fe3O4) pigment, and usually sold pure.

Thanks. Did a search of that and learned they also have Red Concrete Color Iron Oxide Pigment Powder for making those fake brick driveways.

https://www.bestmaterials.com/PDF_MSDS/solomon-concrete-colo...

https://www.smithpaints.com/tech_docs/drypigmentpacks_msds.p...

[Edited on 22-7-2019 by Pyro_cat]

Herr Haber - 22-7-2019 at 03:03

Quote: Originally posted by Microtek

For the iron oxide, consider going to a paint store and buying it. It is often used as a red (Fe2O3) or black (Fe3O4) pigment, and usually sold pure.

Red: Hematite
Black: Magnetite

A friend of mine came 10 days ago to learn how to make thermite.
"But where am I going to get all that from?"

She paints well enough to make a living out of it so I pointed her to her arts supply store !

Pyro_cat - 23-7-2019 at 19:57

Quote: Originally posted by Felis Corax

but electrolysis can be fun in it's own right.

It is fun. I haven't put electricity through water since that time I built a salt water variac when I was messing with microwave oven transformers.

I only have a "smart" battery charger for a DC power supply but its easy enough to trick it into turning on by connecting a battery that's not totally discharged.

Thanks, I am going to go with this electrolysis. Haven't had the motivation for a home depo run just to see if they might have any of this pigment powder. This will be fun.

Pyro_cat - 24-7-2019 at 15:40

The electrolysis turned a steel wool pad into a few tables spoons black muck in about an hour. I just coffee filtered it out of the liquid.

Going to make a some more then try to replicate the Aluminum foil thermite here https://youtu.be/H-PubIM6O_4?t=354 but instead of the roller press I will just have to roll it up and put in in the vice then hammer the wad I get out of the vice for the same effect.

Vomaturge - 24-7-2019 at 21:22

Quote: Originally posted by Felis Corax

You could also make red iron oxide via electrolysis with mild steel electrodes (or iron, but mild steel is cheaply available at the hardware store). When I did it I used NaCl as my electrolyte, which of course produces sodium hydroxide and chlorine gas, so that has to be handled. The result is a goopy hydrate which, when heated, gives a relatively small amount of very fine anhydrous red iron oxide.

Interesting. I've never noticed any chlorine when using NaCl and iron anodes. I think you get ferric and ferrous chloride and sodium hydroxide (well, at least you get the ions to form those) but they react to precipitate goop, which I have seen change from green-brown to orange brown as electrolysis progressed, presumably as oxidation states changed.

The first time I electrolysed salt with a graphite anode, I was kinda surprised to smell chlorine after never having it with iron or copper electrodes. The first time I tried graphite and a substantial fraction of an amp, I was surprised not by the presence of chlorine, but the sheer amount. Had to shut off power and open the window some minutes into the process.

Pyro_cat - 26-7-2019 at 11:53

Thanks,

I used only one salt packet in 4oz of water. The clip on the charger was the cathode. Seems to me less salt would limit the chlorine available to create other compounds. The process started really slow and seemed to self accelerate as the water got dirty with from the products of the electrolysis. The amp meter on the charger moved to about 1 at the end. I broke the rule and smelled it too and did not smell anything chlorinated. There was a green-orange look to it at one point.

The next setup going to get some stainless steel threaded rod for the cathode (lots of surface area) and something iron from the junk pile as the anode in a shoe box size plastic bin.

This was very interesting, Sodium Chlorate from Electrolysis https://www.youtube.com/watch?v=rUvCnyz6ESI If am doing electrolysis in a sodium chloride solution I suppose thats going to happen too.

Did I make Sodium Chlorate in the first experiment and did that lower the electrical resistance of the water allowing more current to flow or was it the iron compounds or both ? I am guessing both.

Turning off the current and Olm testing the solution as its going along is going to be part of this experiment.

Quote: Originally posted by Felis Corax

If this advice seems patronizingly obvious I apologize; I don't know your level of experience.[/rquote]

No problem, a beginner here. At that stage in chemistry of hey this actually works if you follow the directions. Similar place as getting the first little sparks from the Tesla coil project. I can do this !

James Ikanov - 26-7-2019 at 13:20

Just a thought here.

If you know of someplace that has a lathe/mill, etc or have access to a machine shop, I'd speculate that aluminum turnings/shavings/schwarf would be more conducive to blender grinding than foil. It doesn't have the tendency to ball up, and in my personal experience, the small pieces tend to be more brittle, and much less flexible than foils. I have a few jars of the stuff from a machinist friend. playing with it by hand I get the idea that the specific chip size is a matter of some importance for milling vs blending, because it seems like some of the longer and thinner needle like shavings wouldn't work nearly as well, while some of the say, longer and more ribbon like bits are easily broken apart between your fingers. YMMV and it may not be practical, just a thought.

Edit: someone else already suggested something similar for aluminum, and here I am feeling foolish reading the rest of the thread... So I'll discuss how I make iron oxide.

I'm not sure if this advice is applicable to you, but when I'm trying to make iron oxide, I go to the local gun store and buy a bunch of really cheap steel case ammo. I shoot it all, collect the casings, put it in a bucket (about 2/3rds full), and mix in a bit of salt water. The cases have a pretty good bit of surface area relative to the amount of metal so they rust pretty quickly. If you let the water evaporate off, then just shake the stuff up, the cartridges will knock each other to pieces and eventually create a very fine, nearly airfloat mix of iron oxide powder. The primers are a brass of some kind so they'll generally not oxidize and just sort of fall out of the mix. It's a bit time consuming to do by hand but I think it could very viably be adpated up to a ball mill with more or less self consuming media.
The few times I've done it my yields have generally been more in the pound/kilogram range than grams/ounces.

But the advice is useless if you are not in a locale allowing firearms, or if you don't shoot or own them. Although, depending, perhaps you could go to a local gun range and ask if you can have their spent steel casings, even in a less permissive region. I'd bet places really wouldn't care too much. I'm sure the process would really work with any sort of scrap steel or iron, but the advantages of the method go away pretty quickly without something of a similar shape/surface area. I experimented with ball bearings and didn't have much luck. Perhaps cut up sections of a thin piece of pipe, or something along those lines. Something about the size of refrigerator tubing? I hope I'm not cluttering up your thread with something unhelpful.

[Edited on 26-7-2019 by James Ikanov]

Pyro_cat - 26-7-2019 at 19:40

Quote: Originally posted by James Ikanov

steel case ammo

You got me thinking, steal case ammo made me think of "tin" cans and that took me to go big and fill a trash can with water and load it up with empty food cans from a restaurant or recycle day. Might have to hit them with the torch or some sand paper to get past any coatings that may be applied to speed things up. Find enough may have to crush them a bit too.

How did farmers make all that rust to paint barns red back in the day ?

What about a fish tank pump to oxygenate the water ? I believe its the oxygen dissolved in the water not the 2 Os stuck to the H that does the oxidation.

[Edited on 27-7-2019 by Pyro_cat]

Felis Corax - 27-7-2019 at 06:30

The antiquated forum software here on sciencemadness ate my account, along with all my posts. Apparently this happens sometimes.

In any case, rather than re-typing my post on chlorates I'll give you a reference. It's a bit of a recipe, but it discusses electrode materials: Preparing chlorates - PyroGuide

Long story short, no, you didn't make sodium chlorate, you were using the wrong anode type. In the video you referenced you'll note he was using a titanium cathode and a MMO (mixed metal oxide) anode. While the cathode isn't as important, production of chlorates requires an anode that selects for chlorates over oxygen. I don't fully understand the details, electrolysis reaction mechanisms tend toward the byzantine, but that's what the literature says. Selectivity between Oxygen and Chlorine Evolution in the Chlor-Alkali and Chlorate Processes

Pyro_cat - 17-11-2019 at 20:15

I couldn't light blender grade Al + my rust and lost interest in the project for a wile but I just got some containers of iron oxide pigment powder a masonry contractor was throwing out.

All these different colors, very interesting stuff https://en.wikipedia.org/wiki/Iron_oxide

Trying to learn whats unique that makes each color, there is even green, I thought maybe it was a copper compound but its https://en.wikipedia.org/wiki/Green_rust

The tan has a black layer on top that I guess was from what ever it started as further oxidizing.

So I got to grab some balls and start milling some Al. One container is the classic rust color so I will try that first with some milled Al and if that works and no reason it shouldn't, use some of that to see if it will get a mixture using blender grade Al going.

Finally going to see the legendary thermite reaction in real life.

Microtek - 17-11-2019 at 23:22

If you want to use coarse grades of Al for thermite, you just need to get the reactants molten by way of a "booster" made from finer materials. Coarse thermite is actually better in several regards, since a slower reaction means less scattering of the molten products, and more time for the heat to be transferred to whatever you want to heat (and also more opportunity for the molten iron to settle to bottom of the slag).

hodges - 18-11-2019 at 17:07

You might be able to use a low-grade pyrotechnic mixture to get the thermite to ignite. I remember using black powder (KNO3, C, and S mixture) to ignite my thermite test mixes. Just ignite the pyrotechnic mixture with a torch, and it should ignite the thermite. You could also potentially use a a potassium chlorate and sugar mixture and a drop of concentrated sulfuric acid as the ignition source.

Microtek - 18-11-2019 at 22:58

During WWII, some thermite based charges were ignited using a small charge of KMnO4 and iron powder placed in the main charge.

Pyro_cat - 19-11-2019 at 21:51

Maybe I should try the powder inside the little red firecrackers, it burns very bright and left that green stain in my vision when I lit a little pile worse then I expected but bright makes me think its very hot. Or maybe a road flare. Now after thinking that I have to search road flares and see what makes them work, always learning !

We will see. I have KNO3 to mess with too but no KMnO4, can I get that OTC ?

Milling sure takes a wile using small marbles, but the blender bits are now flakes. Started with heavy duty foil, ooops.

[Edited on 20-11-2019 by Pyro_cat]

Bert - 21-11-2019 at 12:34

One might try adding a bit of Sulfur to the top increment. Or using a bit of mixed (finely powdered) Al:S.

https://youtu.be/XfwpYH_qd2I

Pyro_cat - 11-12-2019 at 21:20

That was very interesting, white hot burn followed by a puddle of molten iron left behind just like in the videos. The videos don't really show that white hot burn.

First small batch total of 16 grams the usual ratio using 'airfloat' Al powder lit right up with a sparkler.

2nd batch same amount but using courser Al powder that I added carbon to wile milling wouldn't light.

Then I mixed up another 16g using the fine Al powder without any carbon put it on top of the batch that wouldn't light but only the top batch completely burned.

Is it possible to light blender grade Al thermite ? Don't know yet.

And I just learned thermite can be made with sand https://www.amazingrust.com/Experiments/how_to/Thermite.html

Microtek - 11-12-2019 at 23:42

It absolutely is possible, I have done it myself many times. It does require a certain minimal amount though. The starter mix should be enough to melt a significant amount of the main charge, and I would place it inside the main charge rather than on top of it.

Sedit - 11-12-2019 at 23:51

Just reading through this thread real quick and I figured I would mention aluminum foil is specifically created to be flexible, It might be worth it for you guys to heat then quench the foil before attempting to blend it to make it more brittle, hell I know after hitting it with a blow torch you can turn it into powder pretty much in your fingers. It will likely prevent the balling issue you all seem to be having.

wg48temp9 - 12-12-2019 at 05:45

Quote: Originally posted by Sedit

Just reading through this thread real quick and I figured I would mention aluminum foil is specifically created to be flexible, It might be worth it for you guys to heat then quench the foil before attempting to blend it to make it more brittle, hell I know after hitting it with a blow torch you can turn it into powder pretty much in your fingers. It will likely prevent the balling issue you all seem to be having.

I thought that the reason aluminium foil became brittle after heating to redness was due to it being oxidised, meaning it is so thin that after heating, it is mostly the oxide. It can even become translucent. Though that may be due to lots of small pin holes.

Pyro_cat - 12-12-2019 at 21:14

Quote: Originally posted by wg48temp9

My next search is "tempered aluminum"

Last time I tempered metal was around Halloween a few years ago carving pumpkins with that little blade that comes the kit.
We are all cutting with the little cutters but it kept bending so I stopped and I heated it red hot and quenched it in a cup of water.

People giving me a hard time what are you doing... Bla bla bla

It worked hardened the metal and it didn't bend see easy anymore and worked much better, now they want to borrow my lighter.

Story time over, lets search temper aluminum ... Leads to heat treatment of aluminum alloys

"HEAT TREATING
7075 may be solution annealed at 900°F for 2 hours at temperature, followed by a water quench.... Also, a maximum in strength was found to correlate with a minimum in fracture toughness.

So I guess heating the foil does brittle it but it seems thinner after you heat foil, does some evaporate ?

I was recently making thermite and now I don't have any foil to heat some with a torch to investigate this.

[Edited on 13-12-2019 by Pyro_cat]

Microtek - 12-12-2019 at 23:16

Heating aluminum in air will oxidize the surface layer. With foil that means most of it, which is indeed why it becomes brittle. Heating it in an inert gas will anneal it (make it softer and more ductile). The hardening happens when you quench the hot metal by dunking it in a suitable liquid. Another way that is more applicable to aluminum is to work harden the metal by deforming it while cold. You can do this by hammering it, but it will likely also happen during any grinding process such as in a blender or ball mill.

At any rate, the question is if you can use coarse aluminum in a thermite blend, and my claim is that you indeed can. However, you need a hot starter mix that is large enough to melt some of the main charge. This starter mix should be embedded in the main charge (I prefer a little packet of Al-foil with starter mix). I have done this with foil, and also very large Al particles from milling operations. These are at least 3 times thicker than Al foil, and work just fine.

Fulmen - 12-12-2019 at 23:32

You cannot harden aluminum by quenching. It can only be work hardened or (depending on the alloy) precipitation hardened by "aging" at slightly elevated temperatures (2-300°C).

Microtek - 14-12-2019 at 02:38

Hmm, according to this paper, the alloy series 2xxx, 6xxx and 7xxx are "quench hardenable wrought alloys". I'm not a metalurgist though so I don't have any first hand knowledge. Whether it is true or false, I think it is also academic; I believe we agree that work hardening is the way to go with Al, but even that is really beside the point.

Fulmen - 14-12-2019 at 03:59

The page you're linking to gives a good description of the process, but there's no references to any quench hardening. Besides, those alloys are the ones that are precipitation hardenable. So I expect it to be a misunderstanding of sorts, after all the precipitation process starts with a solution treatment that does involve a quench.

Precipitation hardening utilizes the reduced solubility of allying elements at low temperature. The first step is to heat the alloy to around 500°C, increasing both the solubility and the mobility of the alloying elements. The quench "freeze" the alloy into a supersaturated state. Subsequent aging causes the alloying elements to precipitate out, causing strain in the crystal structure that increases strength.

Quench hardening is pretty specific to carbon steel.

wg48temp9 - 15-12-2019 at 15:05

I was using Al foil in the kitchen today. So I got my butane torch fired up.

By carefully holding the edges of the foil was was able to heat an area to about its melting point as judge by a flat area forming. As the foil is so thin it cools very quickly even from red heat in less than a second

It was difficult to determine if there was any differences in stiffness between heated area and unheated area by bending it or folding it. It was cheap thin foil and very flexible.

With care it is also possible to heat an areas of the foil to a bright redness for tens of seconds. The foil heated to bright redness does not melt if heated again. It retains some ductility as it bends with out cracking and if anything is slightly stiffer than new foil but its difficult to tell by bending it by hand As it does not crack or crumble I assume it is not completely oxide. It also allows some light thru. When examined with a magnifying glass the light appears to get though lots of small holes that are small compared to the separation between the holes. The area between the small holes looks no different in colour than unheated foil and appears to be total opaque just like unheated foil.

My conclusion is that the foil heated to bright redness for about 10 to 20 seconds is probably still aluminium but with a thicker coating of oxide. I do not know what causes the small pinholes. The diameter of the holes are about the thickness of the foil.

Previously I had only examined the remains of foil from trash fires that had been heated for much longer periods.

[Edited on 12/15/2019 by wg48temp9]

Pyro_cat - 20-12-2019 at 22:08

I just got some cheap foil at a discount store, real thin like the inside wrapper on a fancy chocolate candy. Doesn't say on the box how thin.

Tried it too with a little torch and was thinking maybe when the foil melts the surface tension of the liquid Al attempts to pull it into spheres and creates those holes, looked that way but then when I touch it it just flakes away. I need a little microscope, be interesting to use it look at powdered stuff and crystals too.