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[*] posted on 5-4-2010 at 03:53
Thermite for melting steel


Suppose I have a 15mm steel-rod and want to melt through it (just for sports, or because maybe it's too hard for any tool, and acid would take too much time ...)

==> Probably the choice would be thermite ...

So far I did one try, with 50 g of the stuff from sparking-candles:
==> It was placed around the rod, gave lot's of intense light, burned down within 5 seconds ...
==> but the rod didn't even glow ...

==========

==> What sort of thermite would work best ?
==> How much addition of Ba(NO3)2 for extra-oxygen makes any sense ?
==> Does it have to be some sort of "thermite lance" or could it suffice to place the material loosely around the rod ?

etc. etc.

How could the 15 mm steel-rod be completely melted through ?

[Edited on 5-4-2010 by chief]
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[*] posted on 5-4-2010 at 04:05


One of my ideas might be to use some plaster-based thermite ...
==> Would that work even when the plaster would be cast, therefore containing water ?
==> As a mixture of eg. MnO2-based thermite with plaster-based thermite, maybe cured at 200 Cels which would remove a lot of the water but not completely destroy the mechanical stability ... ?
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[*] posted on 5-4-2010 at 04:35


Thermite? There has been found evidence that built-in thermite bombs were used to demolish the WTO Towers and Building 7 in New York on 9/11/2001, by melting through the steel support columns in them. Pools of molten and then solidified steel found in the basements could not have resulted from ordinary fires fueled by the kerosene jet fuel of the planes, which could not have burned hot enough to melt structural mild or low-alloy steel, and certainly not in the only hour or two before the buildings collapsed, - and collapsed so neatly on their own footprints, with visual and audible evidence of explosions on each successive level downwards.
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[*] posted on 5-4-2010 at 04:41


The obvious choice would be an oxyacetylene flame!
The material from sparklers contains little Al but a pile of Al/perchlorate mix might do the job.
Ordinary thermite would melt your steel but it would also produce its own molten iron.
BTW, John, you don't really believe that 'theory', do you?

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[*] posted on 5-4-2010 at 08:12


Quote: Originally posted by JohnWW  
Thermite? There has been found evidence that built-in thermite bombs were used to demolish the WTO Towers and Building 7 in New York on 9/11/2001, by melting through the steel support columns in them. Pools of molten and then solidified steel found in the basements could not have resulted from ordinary fires fueled by the kerosene jet fuel of the planes, which could not have burned hot enough to melt structural mild or low-alloy steel, and certainly not in the only hour or two before the buildings collapsed, - and collapsed so neatly on their own footprints, with visual and audible evidence of explosions on each successive level downwards.

Absolutely incredible!:(
Im sure the mysterious paint on "nano thermite" would do the
trick.Of course the unseen floor by floor enginered charges that caused the pancake collapse were essentil as well.No it was not the natural air compression of collapsing floors causing the "faux paux explosions".Simply diabolical!:D
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[*] posted on 5-4-2010 at 08:19


Ok lets put aside science for the moment. Your experts claim that a well organized group of say 50 people working 24-hours a day in an occupied office building, (of course no one saw them as they had bought cloaks of invisibility on eBay.) Broke down hundreds of walls to expose the buildings columns. After breaking down all those walls they then used sledge hammers to break away the cement block walls around each column. Then after braking
down walls and cement blocks - they scraped off the asbestos insulation sprayed on the steel as fireproofing. (WTC 1 and Part of WTC 2, as the use of asbestos for such uses was banned during the construction of WTC 2. I don't know what it was replaced with.)
Now that all the walls were breach, cement blocks cracked, asbestos scraped. Without anyone noticing, they then brought ton and tons of thermite into the building. Followed by the attachment
to the steel column "some sort" of magic container allowing termite to cut vertical column horizontality.

The work being completed with no one complaining that their offices are now a complete shambles, some method is employed to ignite the termite soon after the planes impact the building. And with terrific planning, the thermite is placed on the same floors that are impacted.

Well if you believe this, there is a bridge not far from the WTC site that I am willing to sell you really cheap.

There is one point not discussed about which I am willing to say that I was wrong. I watched them build the WTC from the digging of the "bathtub", installation of the slurry wall, to the erecting of the steel above ground level. I remember looking the steel supports at basement level and said to myself .... GAD! I have watched a lot of NYC buildings go, but I have never seen such thick steel beam. This building will last forever........ Sad.
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[*] posted on 5-4-2010 at 08:23


The Mythbusters tried to cut a car in half using thermite.
It did not work very well. Its difficult to keep the hot
zone close to where you want it. Demolishing a building
by melting its supports with thermite is rediculous.

Metal cutting tools "burn" the metal as much as melt it.
So you would want an oxidizer that can oxidize iron and
use an excess of the oxidizer. MnO2 seems like a good
choice. You could also try KN03, but the nitrogen generated
may tend to blow the reactants away from the steel rod.

Plasma cutters are a the best way to cut metals. Or
look up a "thermal lance". All these tools use a steam
of oxygen to burn the metal.
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[*] posted on 5-4-2010 at 08:36


In the late 1960's there was a product sold in welding supply stores that was a thermite "bag" for fixing cracks in backhoe blades, etc in the field. This was (as I remember it) bags of 4.4, 8.8 lbs and larger with a special little tube type igniter. They took on a weldment of about 2.5" (for the SMALL one). I have seen themite used commercially and there is NO WAY that thermite could be used to crash a building: it would require hundreds of lbs for a single "I"-beam laying flat.
The supports in a commercial demolition need to be pre-cut (BIG torch cuts) and topple charges need to be positioned over the course of weeks as the formula for dropping a building changes as measurements are taken. NO ONE is going to drag torches into a large populated commercial building in a clandestine fashion. What's more those cut angles and charge positions CHANGE prior to the event.
But the use of thermite is actually a "no starter" for any type of cutting. It does not work in that way. It does NOT burn through an engine block & all sorts of rubbish that popular fiction sets it out to do. It burns and WILL fuse a crack but you need a shit-load! There IS a military thermite "grenade" but it is meant to ruin a computer and things of that nature. It could melt a automobile hood easily & it would RUIN the hoses, distributor cap and other important items in such a scenario.....but I KNOW for a fact it does NOT melt through the car toward China. Thermite levels to even get INTO the engine block would need to be easily 10 lbs or more.
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[*] posted on 5-4-2010 at 08:36


I would use my Plasma torch.

Thermit(e) [Thermite is a registered trade mark] Is not
very good at cutting, it is however, commonly used in welding.
On the Science (?) channel the episode on building the St Lou.
baseball stadium they show it being used to weld railroad track.

For more info I recommend —

Welding Handbook Sixth Edition Section Three Part B Welding, Cutting And Related Processes
American Welding Society Latest edition.

Oxy-Acetylene Welding and Cutting: Electric, Forge and Thermit Welding Together with Related Methods and Materials Used in Metal Working And The Oxygen Process for Removal of Carbon
HAROLD P. MANLY
Chief Engineer The American Bureau of Engineering Chicago
Frederick J. Drake Co. Publishers 1916

Calcium sulphate (plaster of paris) would certainly generate enough heat, it can be cast into whatever shape you desire. It is
important it be oven dried to remove moisture so it doesn't explode from steam pressure. It is hard to ignite, an acetylene/air torch works. Or use one of the standard thermit igniter comps.

"During World War I, binders such as sodium silicate and sulphur or celluloid were added in order to reduce segregation of the termite[®] after loading ; however,these techniques were only partially successful. Thermite® has not been used since World War I for incendiary applications. While the heat released by a
thermite mixture is sufficient to heat the products of the reaction to around 3000oC, the incendiary action is confined to a relatively small area. In order to improve the incendiary effectiveness, several other incendiary composition including several modified thermite[®] compositions, have been tried without success. The composition of some of the incendiary mixtures tried are given in Table 5-9."

"Therm-8" added 0.90 % sulphur and 0.30% castor oil with a large % of barium nitrate.

"Therm 64-c" Added 2% sulphur and an even larger % of barium nitrate.

"Calcium Sulfate Thermite® Consisted of Aluminum and calcium sulphate w/1.0% sulphur and 0.3% castor oil.

AMCP 706-185
Engineering Design Handbook
Military Pyrotechnic Series
Part One
Theory and Application
April 1967

The CaSO4/Al thermit w/ 3 pts "iron oxide" is off the wall. As camouflage, ferric oxide is sometimes added. Details are in one of the low albedo books.


--------
The WiZard's Welding Service —
WE STAND BEHIND OUR WORK.
But never under it.


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[*] posted on 5-4-2010 at 16:00


The American Welding Society's "Welding Handbook" 7th ed Volume 3 says:

Themit(e) welding a 24 x 36" section with a 2 5/8" gap requires .... 3 125 pounds of themit!!

------
Chemical demo goes out of control

An explosion occurred during a chemical demonstration at the University of Illinois,
Urbana-Champaign, earlier this month. The widely used demonstration of the thermite
reaction-which involves the reaction of iron oxide and powdered aluminum to form iron
and aluminum oxide-was part of the university's annual Engineering Open House for
local high school and grade school students. There were 200 to 300 people in the
chemistry lecture hall at the time of the explosion. Four teachers and 23 students were
taken to the hospital, where they were treated and released. The injured suffered first-
and second-degree burns and minor cuts. Chemistry professor Steven S. Zumdahl,
who was conducting the demonstration, says it had just been run successfully using
sand as a receptacle for the molten iron. But when the sand was replaced with water,
something went wrong. Jiri Jonas, head of the department of chemical sciences, says a
committee, including university and local safety experts, has been appointed not only to
determine what went wrong with the thermite demonstration, but also to review all
safety issues surrounding the open house.

March 12, 1990 C&EN23

-------
Föredrag vid PYROTEKNIKDAGEN [Pyrotechnic Day] 1971
Stockholm den 10 maj 1971
Aluminium Powders For Explosives And Pyrotechnics
Gustaf Windqvist

Aluminium powder in explosives
As can be seen from the name of the article, I have tried to deal only with
aluminum powder for explosives.

Mainly I have tried to do this because I do not have any first-hand experience of
explosives and in the audience there is a number of chemists from the explosives
industry, who could contribute to the discussion of the use of metal powders in
explosives and pyrotechnics

As a final vignette I might be permitted to show a rather funny picture of an
explosion in water, which I had the improbable luck to take with a common camera
more than 20 years ago.

At the company we were playing with certain thermite charges, who were
supposed to have a certain effect in undercooked water streams. One of these charges
contained atomized Aluminium powder A 80 and copper oxide in an equivalent mixture.
If such a charge was lighted by a generator-gas match in air, it burned quickly and if it
was lighted by No 8 detonator it detonated and you got a beautiful copper-cloud in the
air. We thought that if it was used under water, with a generator-gas match, it would
burn quickly, but to our surprise, if not a pure detonation, we got a very fast deflagration
I succeeded in taking this photograph of the water-bubble, which emerged just before it
burst You can see a tendency of bursting on the top, and the white dots are
white-glowing charge. See figure 3.


[Two possibilities come to mind.
The temperature of the reaction may have been sufficient to dissociate water into
hydrogen and oxygen, which then explosively recombined. Or this may be a classic if poorly understood “liquid metal water explosion.” ]

Aluminium and water can be detonated.
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[*] posted on 5-4-2010 at 16:11
Dr. Goldschmidt describes his invention - themite


Da FAQ's sez i can post an attachment. So here be it.

Remember this was scanned by me and you know what that means!

The master speaks :—

ALUMINIUM AS A HEATING AND REDUCING AGENT.
BY DR. HANS GOLDSCHMIDT AND CLAUDE VAUTIN.
The Journal of the Society of Chemical Industry (6)17:543-545
June 30, 1898

Attachment: Thermit Journal.txt (39kB)
This file has been downloaded 1220 times

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[*] posted on 6-4-2010 at 07:07


Quote: Originally posted by JohnWW  
Thermite? There has been found evidence that built-in thermite bombs were used to demolish the WTO Towers and Building 7 in New York on 9/11/2001, by melting through the steel support columns in them. Pools of molten and then solidified steel found in the basements could not have resulted from ordinary fires fueled by the kerosene jet fuel of the planes, which could not have burned hot enough to melt structural mild or low-alloy steel, and certainly not in the only hour or two before the buildings collapsed, - and collapsed so neatly on their own footprints, with visual and audible evidence of explosions on each successive level downwards.
I take it this is a reference to the Steven Jones paper. I read it when it first came out, and it is without a doubt the single worst scientific paper I've ever read. Just awful, really. It's no wonder he was suspended and eventually lost his academic job. I don't have the patience to get into this topic in any deep way, but a couple of comments are in order. The molten material seen in the rubble was far more likely some form of slag, requiring a much lower temperature to remain liquid. As for the explosive sounds, it's instructive to look up the speed of sound in steel, as the main columns make quite a good sound conductor, and there would be a point of constructive interference near the bottom of these columns as the front end of an impact wave, broadened by dispersion, interferes with the back end. Finally, I've read a plausible, albeit untested, mechanism for initiating aluminum combustion in the fuselage by SO2 released from gypsum drywall.
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[*] posted on 6-4-2010 at 19:03


Hello, Im going to bust out my favorite thing and say you could use electrolysis to cut the bar. Make it an anode soak it with an electrolyte (posibly heled in a sponge)

The mythbusters did this successfully in a myth called "Salsa Escape" using salsa and the transformer from a small radio.

It would have the advantage of being silent not altering the tempering of the steel bar (if that mattered)
and being much much faster than passive acid etching (allthough it whould probobly still take longer than other methods
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[*] posted on 7-4-2010 at 04:11


Quote: Originally posted by bquirky  
Hello, Im going to bust out my favorite thing and say you could use electrolysis to cut the bar. Make it an anode soak it with an electrolyte (posibly heled in a sponge)

The mythbusters did this successfully in a myth called "Salsa Escape" using salsa and the transformer from a small radio.

It would have the advantage of being silent not altering the tempering of the steel bar (if that mattered)
and being much much faster than passive acid etching (allthough it whould probobly still take longer than other methods


Yes, electrolysis is my second favorite idea ... ; I once opened a lock with it ... (for which there was no key anymore), it took 1/2 hour to go through the 5 mm ...

I also experimented upon electrolytically cutting more massive steel ...
==> but the NaCl-elecyrolyte I used became poor in Cl, therby alcalic and passivated the metal ...

================

Also the goal would be to accomplish the destruction of the bar within maybe 20 or 30 seconds, not minutes ...

[Edited on 7-4-2010 by chief]
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[*] posted on 7-4-2010 at 05:03


Quote:
How could the 15 mm steel-rod be completely melted through ?

Only a cutting torch would go through it in 20-30 seconds. . .

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[*] posted on 7-4-2010 at 07:43


Someone would sneak standard cutting torchs & associated bottles into a secure building....ohh so easy. There are mostly 2 feet long and the bottles are about 5 feet (for the O needed). Total: about 270lbs. Oh...& the need would be about 30 of those units.
Realistically, this could not be done in a clandestine fashion. The level of sparks, slag, and associated heat & smoke would be similar to a Bong-party in a sheriff's office. :P



The large ship-yard torches are much larger than most suspect and use up quite a bit of fuel. Any electrical operated cutting tools would not be portable and run on 480Vac. The weight of an "I" bean is quite astounding for even a small section. The more any of the "conspiracy" issues are actually looked into w/ an open mind, the more they are a serious "NO-GO"....



911-issues.jpg - 158kB

[Edited on 7-4-2010 by quicksilver]
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[*] posted on 7-4-2010 at 08:02


Quote: Originally posted by hissingnoise  
Quote:
How could the 15 mm steel-rod be completely melted through ?

Only a cutting torch would go through it in 20-30 seconds. . .



----------
It would go through a lot quicker that that! 2 seconds or less.

The good old days.

The Oxy-Acetylene Handbook
Union Carbide 3rd ed. 1976


Some Early Exploits
Although oxygen cutting was actually demonstrated at the Seattle World's Fair, shortly after the century opened, commercially-useful torches were not available for several years. In 1907, Eugene Bournonville, one of the outstanding figures in the development of the oxy-acetylene processes in the U.S., showed the U.S. Navy Yard in Brooklyn that 14-inch portholes in armor plate 2-3 in. thick could be cut in 12 minutes.

Before that demonstration, the portholes were being chipped out, after huge kerosene torches had preheated the steel. It had taken two torch operators and five chippers 10 days to cut one porthole. Later that year, American-made cutting torches were used on the demolition of the old Grand Central Station in N.Y. City, at one-twentieth the cost that older methods would have entailed. The next year, three men with cutting torches cut out the four 70-ton structural steel shields which had been used in construction of the H & M railroad tunnels under the Hudson River, a job which would otherwise have required 20 workmen.

In 1910, a 9000-ft. pipeline built to bring water down to hydroelectric generators from a natural reservoir
in Colorado began to leak so badly, only months after it had been placed in service, that some kind of repair was essential. Pipe diameter was about four feet, with walls more than an inch thick at the lower end, where the internal pressure was 825 psi. Butt joints in the pipe had been held together by heavy steel straps riveted to the pipe on both the inside and outside. A half-million dollar investment was in jeopardy. Working through the dead of winter, welders repaired 200 joints successfully, using acetylene generated on the spot from 18 tons of calcium carbide and fed to torches through lines as long as 500 feet, and oxygen made from 23 tons of potassium perchlorate in two stationary plants then compressed into cylinders.

&c., &c.
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[*] posted on 7-4-2010 at 08:38


Quote: Originally posted by chief  
Suppose I have a 15mm steel-rod and want to melt through it (just for sports, or because maybe it's too hard for any tool, and acid would take too much time ...)

==> Probably the choice would be thermite ...


---------
Eugene Song and Gene V Tracy
Enhanced Incendiary Grenade
Proceedings of the Twenty-seventh International Pyrotechnics Seminar. July 2000
Pp. 393-411

"The most basic thermate grenade [see ref for composition] is that of the AN-M14 TH3 ... first produced in 1952." The AN weighs 2 pounds. "It is both heavy and bulky for the solider to carry."

"FM 23-30, Grenades and Pyrotechnic Signals, states that an AN-M14 is capable of penetrating 1/2-inch thick stel plate. However, recent testing.... has shown that the current AN-M14 TH3 grenade is only capable of penetrating 1/8-inch thick steel plate."

"A device with greater penetration capabilities is the "Thermite Penetrator Device, U.S. Pat. No. 4,216,721.....

"While the Frankfort Arsenal device has merit, and a 1.5 pound charge the thermite could penetrate 1-inch steel plate..."

The new 25% lighter EIG [composition in ref.] will penetrate 1-inch of steel plate and will function (with less penetration) when vertical.

The advanced functioning of the EIG is the results of mechanical changes, the chemistry has not changed.

By the - "Stand off" distance is still critical for optimum performance.
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[*] posted on 7-4-2010 at 14:09


Is it terribly far fetched the 'explosions', witnessed by a majority of civilians
who couldnt distinguish an explosion from high air pressure release As the WTCs 100s of acre sized stories pancaked causing explosive air compression/tremendous noise as the millions of pounds of concrete and steel impacted the floor beneath it?Of course they thought the impacting floors were exploding.Nothing mysterious or complex about that.Difficult to believe this is even being discussed seriously on this forum.
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[*] posted on 8-4-2010 at 00:14


An acre-sized surface needs more than a million pounds to compress air enough for explosive sound: Lets calculate:
==> 1 acre =~ 4 000 m^2
==> 1 Pascal is defined as 1 N/m^2 == 100 g /m^2
==> Say one Bar would be needed for explosive sound, then there would have to be a mass of 10 ton/m^2 (!) or 40000 tons per acre ...

.... maybe youre halfway right ... ; but: As explosion it only sounds if it's quick enough ... , else its just wind ... ; also a 1 Bar Air on each floor would have considerably pneumatically taken away the violence, like some damping-system ; the collapse would have to have been slower ...

I would estimate the pressure-rise to at most 100 millibar ...
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[*] posted on 8-4-2010 at 02:28


Grndpndr is 100% right chief - you're forgetting the sound of concrete sheet impacting concrete sheet. . .

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[*] posted on 8-4-2010 at 03:37


Whatever, back to the 15mm steel-rod: Say the idea would be to use a plaster-based thermite, to mechanically contain reaction for optimum-heat-transfer: Can plaster be made the usual way, just with aluminum-content, poured into shape and then be ignited ?
==> Or will it be too moist ? Do plaster-thermites function only with unhydrated CaSO4, or is hydrated stuff usable ?

Going to find out this weekend, but some previous inspiration would be fine ... :D

================

And while we were talking about some specific demolition: I read somewhere that
==> the inner core-columns were made to support 3 times the weight of the entire building
==> and the outer walls together could hold again 3 times the weight ...

With one destructed wall and a completely demolished inner core that would still make a capability to carry 3/4*3 == 9/4 of the total weight of the building ... right ?


[Edited on 8-4-2010 by chief]
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[*] posted on 8-4-2010 at 10:06


Quote: Originally posted by chief  
Whatever, back to the 15mm steel-rod: Say the idea would be to use a plaster-based thermite, to mechanically contain reaction for optimum-heat-transfer: Can plaster be made the usual way, just with aluminum-content, poured into shape and then be ignited ?
==> Or will it be too moist ? Do plaster-thermites function only with unhydrated CaSO4, or is hydrated stuff usable ?




Plaster can be cast the usual way. It will need to be dried in an oven at 90C for a while to dry it out.




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[*] posted on 8-4-2010 at 11:33


Quote: Originally posted by chief  
Whatever, back to the 15mm steel-rod: Say the idea would be to use a plaster-based thermite, to mechanically contain reaction for optimum-heat-transfer: Can plaster be made the usual way, just with aluminum-content, poured into shape and then be ignited ?
==> Or will it be too moist ? Do plaster-thermites function only with unhydrated CaSO4, or is hydrated stuff usable ?

Going to find out this weekend, but some previous inspiration would be fine ... :D


Because aluminium when milled is lubricated wetting it is...!
Spherical (atomized) is the easiest to use. As you are only
going to burn it ... use the lest expensive Al pwdr you have.

Drying to "constant weight" is recommended to prevent entrapped
water causing a steam burst. Any temperature will do your oven
does not get close it its ignition temperature.

The low albedo book sez. aluminium/sulphur will ignite it. I would
use one of the standard igniters

I don't remember, but I seem to remember you need K chlorate
sugar to ignite the Al/S. Do NOT use confectionery sugar.

Aluminium atomized (fine) 40%
Black iron oxide 29
Barium peroxide 31

Magnesium powder 9%
Barium peroxide 91

Silicon 40%
KNO3 54
Charcoal 6

Will ignite just 'bout any thing. The silicon results is a nice
hot dross/scoria of Si dioxide.

AMCP 706-185 Engineering Design Handbook
Military Pyrotechnics Series Part One
Theory and Application April 1967
[You can DL a copy of this and the other volumes in the Pyro series from the obvious US Gov web site.]

Sez —

Calcium Sulphate Thermite

Aluminium 40.9%
Sulphur 1.0
Castor oil 0.3
Calcium sulphate 57.8

I have never added sulphur or castor oil.

Checking my DB if find this comp was patented 1947.
US Patent 2 424 937, which see for details.

US Patent 5 490 888 and 4 381 207 are a variation.

I would mention in passing you can make firecrackers from
P of P and aluminium powder.

Byda you can read my article on the use of sulphates of oxidizers
in the Pyrotechnist Guild International bulletin.
The Few, The Proud, The Sulfates Bulletin No. 46





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[*] posted on 8-4-2010 at 13:25


I saw a video once (on roguesci) where thermite with an added gas generating component (possibly blackpowder) was contained in a ceramic "bottle". The device was pointed at a rebar and ignited from the open end, which resulted in a short but extremely hot jet of material from the opening of the bottle. This cut the rebar in less than a second.

IIRC, this wasn't an amateur experiment, but rather a video demonstration by some company.

I did a small scale feasibility test using "fireproof" clay as the container, and smokeless powder as the gas generant. It looked much like the demonstration in the video, but I didn't aim it at a target, so I don't know how effective it was.
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