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Author: Subject: Peroxide Watergel
Axt
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[*] posted on 10-1-2005 at 14:15
Peroxide Watergel


The science of commercial watergel explosives is an art unto itself, where a balance of fuels (eg. Aluminum/oils), oxidisers (typically AN), binders and crosslinking agents are combined within just the right ratio's, combined with gas producing components to give the microscopic gas bubbles necessary for sensitisation. One component that can be used for this is hydrogen peroxide.

Heres an experiment to see if the H2O2 is capable of the role of oxidiser as well as sensitiser. Theoretically the H2O2 will slowly decompose in contact with aluminium providing the vital gas voids by enveloping the Al grains in an oxygen bubble. The Aluminium providing the source of fuel, and combined with a binder to hold it together.

Watergel's are workable, at least partly due to aluminium's ability to draw its oxygen from water: 2 Al + 3 H2O -> Al2O3 + 3 H2 + 226 kcal/mol Al2O3

So the formulation with 50% H2O2 was calculated to be 50:50 peroxide to Aluminium by weight (this ratio is the same for 30% etc. as well!), this is balanced to H2 and Al2O3 products. The final formulation used was 50% of 50% peroxide, 48% 200 mesh aluminium and 2% guar gum to bind the explosive into a soft mouldable putty. The explosive is a stable putty for about 6 hours, although it expands somewhat. After this time it turns to liquid. So it is a "mix on site" explosive.

H2O2 was hydroponic nutrient, aluminium was resin filler and guar gum was bought as a food ingredient (for what I dont know!).

The components were mixed, left for two hours, then fired with 0.5g PETN, six consecutive frames from this blast are shown below.

<center><img src="http://www.sciencemadness.org/scipics/axt/peroxygel.jpg">
<a href="http://geocities.com/roguemovies8/">MOVIE</a></center>

The 100g charge detonated with a gutsy BOOM, bright flash and considerable air movement. Its a nice "spectator explosive" :cool:

Further experiments could be done to deterimine the concentration of peroxide it will work over, the mesh size and its time window where it is usable after mixing. The blast shown is the only time I have tried it, but it seems to be an easy, expedient explosive that most will have access to.

Magnesium can't be used, it decomposes H2O2 too fast, acting more like an expanding foam, which could be dangerous due to the heat release.

[Edited on 9-12-2005 by Axt]
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chemoleo
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[*] posted on 10-1-2005 at 15:15


Axt and his nice exotic EM's - what would we do without him/them? :o:cool:

Anyway - you say explosive - what was the effect on the surrounding material?
Presumably it's a low-order explosive... ?


Oh, and by the way, I am sure you heard of the ability of agarose forming gels.
A 1% gel is quite solid, and a 2 % hard to press between your fingers.
There are several kinds, the one used in molecular biology is mostly the kind that melts at 70 deg C, but there are some that have a MP of 28-40 deg C.
Maybe you could use that as a binder/gelfactant?




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[*] posted on 10-1-2005 at 16:27


Yeh, OK. I know it <i>looks</i> like I burnt a handfull of blackpowder, but this is definately a HE! The second frame is the flash on detonation blinding the camera, where the rest are the excess H2 released burning up. It was confined in a thin flexible plastic container, with a "pop on" lid, so confinement wasn't siginificant. Download the movie and it will all be clear :)

There was nothing in its vacinity to get a good idea on "power", but the ground was turned up, and grass flattened.

Nope, I'd never heard of agarose forming gels. I look into it once I get some sleep. Gelatine may be a more readily available binder, though im not sure what crosslinker will hold it together without decomposing H2O2.

[Edited on 11-1-2005 by Axt]
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[*] posted on 10-1-2005 at 16:55


Hmm, but the brightness of a flash is not a measure of its ability to detonate? Can't download the movies, because of 'data transfer rate exceeded'.
The reason why I am asking/wondering is because it reminds me much of other Al-based low explosives. They all give a bright explosion, and a loud report. But these aren't high VoD explosives right.

Gelatine is another option, but its gels arent as solid as those of agarose, and again it needs high temp for dissolution. I haven't tried it, but maybe its not such a good idea to dissolve gelatine in boiling 30% H2O2? But then, if there is no problem with it, why not :) In taht case, you could use high melt agarose, its gels are stable for several days, they just dry. Another option are polyacrylamide gels - which is probably the best one. But with H2O2 - I imagine polymerisation is about instantaneous.




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[*] posted on 10-1-2005 at 17:23


I'm not claiming a high VOD explosive, just that its a true detonation. I expect that you could safely chuck this stuff into an incinerator without explosion.

Guar gum is the best anyway, pre-mixed with Al powder, once your at the blast site, just pour the required H2O2 over it and knead it in with gloved hands, simple!
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[*] posted on 11-1-2005 at 12:22
Just curious...


I was talking with a friend of mine who runs a local blasting company, and he was saying his "Amex" (AN) would VoD between 8,000 and 12,000...in 4" holes and the gel type he uses will go up to 15,000 VoD. However he said the AN has better breaking power and he prefers it (cheaper price to obviously), even though the other has a higher VoD...so my question is, why would the AN have better breaking power with a lower VoD? I don't get it...and secondly have you any idea what the general VoD would be for your gel mix? I'm enterested in other uses for H2O2...seems such a versitile chemical...sheesh. Although limited in some respects...
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[*] posted on 12-1-2005 at 02:31


Dunno, depends on the definition of "breaking power" and how well it's been interpreted into here. Emulsions typically have considerably greater bulk strength then that of ANFO.

I've been searching PATR for info on the explosive interaction of water/Aluminium, heres one entry that most closely resembles the topic of this thread.

<center><img src="http://www.sciencemadness.org/scipics/axt/al-water.jpg"></center>

I expect the peroxide containing explosive to be equal or greater in explosive effect to these. Someone may like to try detonating Mg/water, Mg/MeOH or Al/water alone. But I expect you would need very fine mesh sized metal, and a decent booster.

More relevant quotes relating to Al or water or peroxide containing explosives:

Quote:

H202/H2O/EtOH detonation rates could be as high as 6700m/s.

A 90.7% (H2O2/water) soln detonates at 5500 to 6000 m/sec even at 0.5 inch ID and 25.

A further advantage of the addition of Al lies in the fact that Al2O3 formed during the reaction does not remain as a solid but vaporizes, thus increasing the overall volume of gases and the pressure. These increases are due to the fact that the bp of A1203 is only 2980° while the temp developed on expln of HE’s is usually above 4500°.

They were also found very effective in Aerial bombs (because their radius of blast damage was greater than with nonaluminized expls). The large amts of heat liberated by these reactions maintain a high pressure of expln for a longer period of time than would be obtained without Al.

They found that Al powder mixed with a stoichiometc amount of liq oxygen to form Al203 is a very powerful expl, giving 3.85 times the arnt energy of an equal wt of TNT.

Water content influences Slurry strength. Dupont Trade Literature claims that each % of w removed increases strength by about as much as the addition of 1% of Al. Cook (Ref 9, p 215) also shows that increase in w content reduces strength. However, according to Cook, this effect disappears in highly aluminized Slurries.

According to an investigation by Medard (Ref 3), mixts of Mg + H20, Mg + MeOH or 2Al + 3H20 are comparable in their power to guncotton but they are not able to propagate the deton unless a small quantity of a sensitizer (such as 7%+ of PETN) is incorporated.

A mixture was prepd by treating cellulose with 83.4% H202 to form a gelatinous mass. This mixt is more powerful than TNT or Tetranitroaniline.


[Edited on 9-12-2005 by Axt]
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[*] posted on 12-1-2005 at 07:11


Doubling the amount of guar gum to 4% results in a more plastic mix, and holds together for longer. Can't confirm that it will detonate presume that it will. 48:48:4 ratio is seen in the pics below.

<center><img src="http://www.sciencemadness.org/scipics/axt/pergel1.jpg">
Moulded around a 4mm rod, it let go after 45min.</center>


<center><img src="http://www.sciencemadness.org/scipics/axt/pergel2.jpg">
After 6 hours it still holds its shape, though it does "droop" if left stand.</center>

[Edited on 9-12-2005 by Axt]
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[*] posted on 12-1-2005 at 09:59
Resin Filler


for your source of Aluminium?

Wow - I bought some resin filler Al and found it to be remarkably unreactive. It was very grey in colour and of a mesh similar to icing sugar - maybe a <i>tiny</i> bit coarser. But when mixed with KClO<sub>3</sub> or NaNO<sub>3</sub> in the correct proprtions I got little more than the odd spark. So I figured it was either that the particle size was too big or that it was coated with something. Do you treat yours in anyway before using it? Or maybe it just needs a good kick (blasting cap) or siginificant confinement and heat to get it going. Or maybe I simply didn't mix it well enough...
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[*] posted on 12-1-2005 at 10:25


No, a KNO3 'fuse' (paper soaked in KNO3) was also not enough in my case to set off NaClO3/Al - 200 mesh, also for resin filler. You need more heat to start it off. A small amount of NaClO3/sugar sufficed, it then burns with a supremely white flash.

Anyway, BACK to topic please!
Axt, I expect you will be trying this with H2O2/MeOH/Al?
The more I think about it, the more I like it - as the H2 produced also burns in the air, so it is somewhat an FAE!.




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[*] posted on 12-1-2005 at 13:24


I'm not sure if adding methanol will be useful, since to add MeOH, you decrease the concentration of peroxide which I now know to be vital, as I just tried to detonate 25% peroxide in the 48:48:4 ratio, but it failed. I've also previously tried to fuel 50% peroxide with ethanol but to no effect. I like the idea of using plain ol' peroxide/Aluminium to create an HE. I dont have methanol, but im sure others will be able to try this.

Anyway, the bit of gel in the photo above, near the matchbox was just fired 12hrs after being mixed. Full detonation, confinement was only a couple layers of cling wrap (film you wrap food with) which I used to keep peroxide off my hands. Gelled 50% H2O2 under your fingernail is incredibly painfull :mad:

The charge was placed on 2mm steel, which was used previously for the ANNM and MEKP charges. The steel was leaned up against a stump, a branched leaned up against it, and the charge placed onto the branch so it sat up against the plate. The plan was to try and see the blast move through the grass as I wasn't expecting much effect on the plate ... I was wrong. It ripped the corner off the plate.

<center><img src="http://www.sciencemadness.org/scipics/axt/peroxide-watergel1.jpg"></center>

It's explosive effect was much more then the other explosives tested on it. The charge size was 85g, which occupied about the same volume as the MEKP charges. See the MEKP thread for description of those charges, how they were setup and their effect.

Someone with 600 mesh aluminum might want to try using it with the more common 30% peroxide to see if they can get a detonation. It may also be advantageous to add a tiny amount of copper powder to the 30% peroxide mix to help catalyse its breakdown, providing the sensitising bubbles.<br><br>

[Edited on 9-12-2005 by Axt]
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[*] posted on 12-1-2005 at 15:49
H2O2 percentage


AXT,
are you saying that 35% H2O2 can not be used for the slurry or does it just require tweaking.
Well done on the tests though 50% H2O2 is probably quite difficult to aquire by most of us.
Damn impressive test though and were are you getting the gum from?




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[*] posted on 13-1-2005 at 01:00


Quote:
Originally posted by chemistr1
are you saying that 35% H2O2 can not be used for the slurry or does it just require tweaking.


I'm saying 25% peroxide wont work in that ratio, when fired under no confinement with 0.5g PETN. Its also old 50% peroxide that im using, so it could be down around 40% and 20% peroxide that I tried. I don't have finer Al then 200 mesh, finer would be prefered.

The guar gum is some sort of thickener used for food. It's probably not available in supermarkets. But a google search should provide many sources since it is quite common, health food supply etc. <a href="http://www.iherb.com/guargum1.html">here</a> for example.

You could try other thickeners such as starch or gelatine, which would create more of a slop then a plastic. Effectively you just need something to hold the Al in suspension, and preserve the oxygen bubbles created.
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[*] posted on 13-1-2005 at 15:45


I have obtained guar gum from ceramics suppliers...
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[*] posted on 13-1-2005 at 17:00


Guar Gum is used for dieting. Mix it with water and it fills you up. No longer hungry. Get in health food shops and online.
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[*] posted on 14-1-2005 at 07:55


I've been passed a patent # via U2U relating to H2O2 "sprengel" explosives in general, but of the examples given is Al/H2O2 While it only relates to concentrated peroxide (90%) some info may be gleamed from it. See attachment.

There is a couple things I dont like about it, example, the formulation was calculated off a standard OB formula, not taking into account Al/H2O reactions. Also no binder is used for a formulation very heavy on the liquid portion, I cant see holding any sort of consistacy throughout the mix. An idea that it presents however, and I have now confirmed true is that 1.5% added ethanol will help blend paint grade Al into the peroxide, due to its oil coating. The picture below shows the lustrous paint grade of Al powder in the mixture. The patent refers to this grade Al as being superiour to 200 mesh, and it does look cool :cool:

<center><img src="http://www.sciencemadness.org/scipics/axt/paint-al.jpg"></center>

[Edited on 9-12-2005 by Axt]

Attachment: peroxide-explosives-patent.pdf (260kB)
This file has been downloaded 1785 times

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[*] posted on 16-1-2005 at 04:26


Hello all I bring greetings from Tasmania.

Axt I am most joyus with this explosive as all the chemicals are readily availiable ( assuming I can get guar gum) I WAS going to use the 50% H2O2 thats on its way for MEKP,HMTD and AP but I like this better, I will utalise the -325 mesh aluminium (spherical) I am getting for this.

Has anyone been able to set off the 48:48:4 mix with pressed AP or is ENT/PETN totally nessicary?
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[*] posted on 16-1-2005 at 04:58
What type of aluminum?


I found this website and before I email and ask to many possibly pointed questions, can anyone suggest what type of aluminum I would want to order that has the most usefulness or that looks familier to them? I have no clue from the list what would be best...Thankyou!
http://www.sheffieldbronze.com/products/aluminum/#Powders
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[*] posted on 25-1-2005 at 04:59
Poonus hydro shop


DAMN THEM
No 50% H2O2 :(
They are getting it in tho yay, Also i found out that one of the larges Al powder manufactures in the world have a depot in Tasmania (Im in Tasmania :D).

So i may be abloe to work with 600 mesh Al :D:D
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[*] posted on 2-2-2005 at 16:31


Intrigued by Axt's experiments I've been reading the USPTO database results for search : " water gel explosive ".
What I don't understand is how the density reduction by incorporation of gas bubbles, organic microspheres or glass microspheres increases sensitivity.
Anybody care to offer some insight?
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[*] posted on 2-2-2005 at 18:23


I just had a go a this experiment. I used 50% peroxide - my aluminium had no mesh numbers writen on the label just
Al Mol. Wt = 26.98 - I could not get guar gum locally so I used Xanthan gum. This gum should be availible everywhere it is sold by the Coeliac Society $4.00 for 100 grams, every state would be bound to have one. I believe the Xanthan gum is used in cooking for people who have allergies to glutten. The mix was more of a slop than a plastic, but it looks good and is very uniform with no lumps. Next time I will add more gum.I will just leave it be for now and see how long it takes go back to liquid. I used 50 grams peroxide 48 grams Al powder and 2 grams Xanthan gum.
Just a question about paint grade Al. I have been trying to locate it and am having some difficulties. Is paint grade Al a additive to paint or already in the paint? I cant find any additive and the salespeople say they have never seen it. I have a can of paint labeled Brillant Aluminium . I can spoon a heap of aluminium goop from the bottom of the can buts it very oily and even after three days it not dry. Definitely not a powder. Any pointers in the right direction? Thanks for sharing this composition Mr Axt.
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[*] posted on 2-2-2005 at 22:34


I've attached the Urbanski explanation of gas voids = sensitivity.

It's interesting that xanthan gum cooperates with guar gum, creating a stiffer gel then either alone. So a mixture of guar/xanthan would be ideal.

Paint grade Al is an additive, coated in a light coat of oil to maintain its luster. Its very light "flowy" stuff that floats around everywhere and is very messy. Better bought as a resin filler to give the resin a metallic look. I guess you could clean the paint with xylene to retrieve the powder, likely not worth the trouble.

[Edited on 3-2-2005 by Axt]

gasbubbles.jpg - 74kB
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[*] posted on 3-2-2005 at 09:40


Quote:

Better bought as a resin filler to give the resin a metallic look. I guess you could clean the paint with xylene to retrieve the powder, likely not worth the trouble


Don't ask for it at a paint store, they have no interest in helping you make your own paint! Instead, investigate ART SUPPLY companies, especialy those selling casting resins and fillers. I have found several useful powdered metals this way...
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[*] posted on 3-2-2005 at 13:55


Just a update on my experiment. Had a look at the putty this morning - still putty has not leaked the liquid out after 18 hours. One thing I did notice is when the powergel was weighed this morning it was 76 grams so I lost 24% over 18 hours. I made the stuff in a pyrex glass bowl and it was not covered, so maybe this stuff has to be kept in a air tight container. Went to blast it using 4 grams HMTD. Think I had a misfire but not sure. Saw some white smoke like in the video and some blast damage but it was very quiet compared to other detonations I have heard. I placed the charge at the base of a tree, it dug the dirt up around the tree and stripped the bark off the base of the tree. I found some of the sandwich bag it was contained in. So the plan for today is to make some more, keep it air tight and use a bigger cap.
Made another batch this time with 4 grams of xanthan gun. Much better consinstency. Wrapped the putty in cling film straight away and tested it. I ended up 97 grams as some stuck to the bowl. Used a 28 gram cap this time. No problem full detonation. :D I love this stuff! Takes around 5 minutes to make and for me around $32.00 per kilo.
After cleaning up after myself I now realize my report of 24% loss of product is not right. I probably lost 3 grams left in the bowl and a couple more left on the sandwich bag I used to knead the mixture.




[Edited on 4-2-2005 by fatkangaroo]

[Edited on 4-2-2005 by fatkangaroo]
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[*] posted on 7-2-2005 at 21:36
W00T!!


Go me! I found 600 (close to) Al In Aus so I can use it for peroxide watergel, now to find a hydro shoppe that carries 50% H2O2. Hmmm...
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