holmes1880
dushbag
Posts: 194
Registered: 13-12-2010
Location: http://highexplosivesforum.forumotion.com/
Member Is Offline
Mood: Egregious
|
|
Igniting Thermite in Confined Space
Has anyone had consistent success igniting thermite in a confined space? Now, I'm talking iron oxide/al thermite, but for the heck of it throw in a
more energetic LE CuO/al thermite. I have failed to light Fe2O3 with magnesium filings (!!!) and copper oxide just behaves like it pleases. Tricky
thing is that to even use Mg you have to have the whole mix in an open air, as Mg doesn't burn without it. And if you use KMnO4/glycerol, then it's
still an absolute pain to combine when confined in an airtight container.
Have you found/heard/tested any plausible ignition means of Fe2O3/Al or Fe2O3/Mg......both performed horribly. No ignition even in open air. When
airtight, it's futile. My hope was to test it out underground or underwater with ammonal to see if it can detonate it via thermal shock. Long shot,
but it is interesting. Would ya'll agree?
[Edited on 17-12-2010 by holmes1880]
|
|
|
The WiZard is In
International Hazard
Posts: 1617
Registered: 3-4-2010
Member Is Offline
Mood: No Mood
|
|
Quote: Originally posted by holmes1880  | | Has anyone had consistent success igniting thermite in a confined space? Now, I'm talking iron oxide/al thermite, but for the heck of it throw in a
more energetic LE CuO/al thermite. |
I have never had trbl igniting Cu oxide - Aluminium thermit,
however, I don't remember which oxide I used. The standard
igniter for thermite dobe two —
Aluminium atomized (fine) 40%
Black iron oxide 29
Barium peroxide 31
Magnesium powder 9%
Barium peroxide 91
Try a little aluminium/sulphur atop magnesium.
[A few years back someone sold 10-lbs of BaO2 on eBay.
Don't know who bought it maybe the same person who bought
the 12-lbs of white arsenic and the paris green. Who knows?]
[Edited on 17-12-2010 by The WiZard is In]
|
|
|
The WiZard is In
International Hazard
Posts: 1617
Registered: 3-4-2010
Member Is Offline
Mood: No Mood
|
|
| Quote: Originally posted by holmes1880 | | Has anyone had consistent success igniting thermite in a confined space? Now, I'm talking iron oxide/al thermite, but for the heck of it throw in a
more energetic LE CuO/al thermite. ] |
Just be remembering ... some years back seeing a
common firework sparkler used to ignite Cadweld
{Cu oxide - aluminium) thermite used to weld ground
(Earth[ed] for you on the other side of the pond) wires.
Have not I (yet) tried it w/ one any of the three
iron oxide thermite compositions.
|
|
|
mabuse_
Hazard to Self
Posts: 56
Registered: 3-6-2010
Member Is Offline
Mood: No Mood
|
|
I recently tried CuO Firecrackers with both "Black 000" Pyro Aluminium (5µm) and 63µm Magnesium.
I used 2mm green visco, no problem.
Aluminium was nice, but Mg seemed even stronger. A real Flashpowder substitute 
Fe2O3 Thermite is troublesome.
Last time i used cheap 350 mesh atomized aluminium with 2 step priming.
First comes a lump of dextrinated blackpowder with visco fuse casted in, inserted in a spraycan cap filled with Fe2O3 and 50/50 Al and Mg. Then comes
the main charge, surrounding the cap.
I could watch the blackpowder burning for some time, until the cap literally exploded and ignited the rest. The blackpowder was barely hot enough. For
next time I'm going to add some magnalium.
|
|
|
holmes1880
dushbag
Posts: 194
Registered: 13-12-2010
Location: http://highexplosivesforum.forumotion.com/
Member Is Offline
Mood: Egregious
|
|
Well, I ignited CuO/Al, Al being 650mesh, with a fuse too, but after a while it stopped igniting(maybe Al got too oxidized, or maybe the overall
humidity). Regardless, it was still not a sure way to ignite CuO/Al. I'm looking for the method to ignite slower thermite compositions like Fe2O3 and
other similar mixes as manganese dioxide and chromium oxide.
Even though Richard Nakka's test show it can be done easily, I've had far inferior results with much finer Al than he used. I need an oxygen
sufficient mix.....like BP only 10 times hotter.
http://www.nakka-rocketry.net/thermites.html
[Edited on 18-12-2010 by holmes1880]
|
|
|
plastics
Hazard to Others
Posts: 141
Registered: 6-11-2009
Member Is Offline
Mood: No Mood
|
|
Potassium permanganate and glycerin hasn't failed to ignite a thermite for me yet. Also provides a sufficient time delay to retire to a safe distance
Ignore that just read the whole of your first post!
[Edited on 18-12-2010 by plastics]
|
|
|
holmes1880
dushbag
Posts: 194
Registered: 13-12-2010
Location: http://highexplosivesforum.forumotion.com/
Member Is Offline
Mood: Egregious
|
|
I genuinely dislike thermite for this specific property of being so problematic to ignite. I have a 1lb of CuO and another lb of Fe2O3 sitting on my
shelf never to be used again. Such a pity and a waste of $20.
|
|
|
quicksilver
International Hazard
Posts: 1820
Registered: 7-9-2005
Location: Inches from the keyboard....
Member Is Offline
Mood: ~-=SWINGS=-~
|
|
A long time back thermite was used industrially for the field repair of backhoe blades (cracks) and had a whole kit (which is no longer available).
But some of the advertisements indicate that a separate ignition unit was supplied. It is VERY dangerous to use as the fire danger was staggering. But
it did repair cracks, etc.
The item was sold under the trade name of thermate (I don't remember the mfg) but it was effective for mild steel. The use today of hardened stick
electrodes provided the attachment and hardened weldment; which is what is used now. Too many problems were involved and the "cone" was never designed
to be under the level of control that a SMAW could be.
A great deal of information could be found under that trade name.
Today the hardened electrode is used to seal the crack and make (usually) and "X" pattern on the blade thus exposing the hardened pattern to the
contact surface.
Underwater welding is a whole science / art and demands high levels of skill and metallurgy knowledge.
There is also a military unit used for the destruction of cryptographic equipment that is also very rare or no longer mfg. but it was designed to burn
into light steel. Patent available via a hunt for "cryptographic equipment destruction", etc. I don't think it is a realistic thing to produce on
anything but a plant-level basis.
[Edited on 20-12-2010 by quicksilver]
|
|
|
SB15
Harmless
Posts: 45
Registered: 23-12-2010
Member Is Offline
|
|
A slow burning mixture of KNO3, S, and coarse flake Al has always worked reliably for me. It is fuse sensitive and will ignite confined
Fe<sub>2</sub>O<sub>3</sub>/Al thermite.
|
|
|
holmes1880
dushbag
Posts: 194
Registered: 13-12-2010
Location: http://highexplosivesforum.forumotion.com/
Member Is Offline
Mood: Egregious
|
|
| Quote: Originally posted by SB15 | | A slow burning mixture of KNO3, S, and coarse flake Al has always worked reliably for me. It is fuse sensitive and will ignite confined
Fe<sub>2</sub>O<sub>3</sub>/Al thermite. |
This is interesting! Some key questions, though:
1. What were the raitos?
2. This looks like nitrate flash powder composition, so did you add boric acid?
3. How long does it take for the ignition to take place once the kn03 mix is lit?
If this actually ignites thermite being airtight, sky is the limit.
[Edited on 23-12-2010 by holmes1880]
|
|
|
SB15
Harmless
Posts: 45
Registered: 23-12-2010
Member Is Offline
|
|
The composition I typically used was 60% KNO<sub>3</sub>, 25% paint grade Al, and 15% S, with a small amount of boric acid to stabilize.
Very fuel rich, but it gives a nice long, hot burn. The sulfur is required because the Nitrate/Al mixture won't sustain combustion on its own.
If the charge is well placed within the thermite, ignition only takes a second or so to occur.
|
|
|
holmes1880
dushbag
Posts: 194
Registered: 13-12-2010
Location: http://highexplosivesforum.forumotion.com/
Member Is Offline
Mood: Egregious
|
|
SB15,
Ok, so boric is a good idea. Very good that it doesn't take too long to ignite. I will definitely try this mix with iron and copper oxide thermites.
|
|
|
Saerynide
National Hazard
Posts: 954
Registered: 17-11-2003
Location: The Void
Member Is Offline
Mood: Ionic
|
|
One word: Sparklers  For a longer fuse, bind several together with steel
wire, making sure the dipped parts have sufficient overlap (like 1-2 inches). Just stick the sparkler into the thermite pile. I believe sparklers do
not require oxygen to burn, but I've never tried burning sparklers in an anoxic environment to test.
So I guess if you want to do it underwater, you can try putting the whole thing in an airtight container, and wire an electronic ignition to light the
sparkler which then sets off the rxn?
I have not been able to get Fe2O3 thermite to start using only electronic ignition.
Mg and KMnO4/glycerin have never worked for Fe2O3 thermite in my experience. Sparklers start it every time though.
[Edited on 12/24/2010 by Saerynide]
"Microsoft reserves the right at all times to monitor communications on the Service and disclose any information Microsoft deems necessary to...
satisfy any applicable law, regulation or legal process"
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
