Sciencemadness Discussion Board

Flash Powder

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Blaster - 1-9-2004 at 09:09

Here's a simple recipe for flash powder I've been using for years. In fact I can attribute my interest in explosives and even chemistry to it because it is so versatile.

By volume: potassium permanganate 2 parts, Aluminium powder (the finest flour-like grade) 1 part, powdered sulphur 0.5 part.

To prepare, grind the KMnO4 to the finest possible powder in a mortar. You know when you've ground it enough when it changes in colour from dark purple to a lighter purple.
Clean the mortar then mix the Al powder and sulphur together.
Finally add the KMnO4 and mix gently, do NOT grind!

This composition will burn much faster and hotter than black powder and is vastly superior for making cannon crackers or any firework requiring an explosive charge. It explodes without fail when confined in any way (if prepared as above).

However this composition has an even better property, namely it can be ignited by adding a drop of glycerine. This reacts with the KMnO4 and gets so hot it ignites the mixture.
The mixture usually takes around 20 seconds to ignite depending on ambient temperature.

This is great for setting off a sequence of explosions without using a flame - simply add a drop of glycerine to each charge.

Alternatively, place the flash powder in a container with a screw-on lid. Add the glycerine and QUICKLY tighten the lid before throwing into water - hey presto an UNDERWATER explosive.

Here's a demo:

Flash powder and eye dropper full of glycerine.



Add a drop of glycerine.



20 seconds later (bit too close to the Porsche for comfort!)


chemoleo - 1-9-2004 at 10:11

Nice pictures.
I didn't know of that mixture... but tsts - making perchloric acid esters but yet measuring powders by volume? :P Have you tried to find out whehter parts by volume arrive at stoichiometric quantities?

Anyway, please be reminded that this is a forum that doesn't focus on practical discussion of explosives/pyrotechnics - unless it is in some way unusual (i.e. not the bog-standard AP, or NG, or blackpowder) - as this has been discussed in depth in other forums (and this thread is a borderline case... )
So let's keep this thread to unusual mixes - no discussion of your latest BP /chlorate flash experiments. Let's see where this gets us - it can always be closed later... (unless other mods/admins object anyway :()

[Edited on 1-9-2004 by chemoleo]

sylla - 1-9-2004 at 10:23

I've tested several flash powders and I use only those : (in mass)

3KMnO4 + 2Al + 1S which burns really fast and is really easy to explode (even in a opened cardboard tube !!!) But it is very sensitive...

3Ba(NO3)2 + Al + 0.5S which is more stable compared to the KMnO4 one

I hope this will help you =)

Edit : Funny Thing : when the mixture has burn just add water, smell the H2S it's nice ;)

[Edited on 1-9-2004 by sylla]

Blaster - 1-9-2004 at 11:03

Chemoleo - I'm aware of the practical side but thought the glycerine aspect would be of interest and, as you say, not the usual acetone peroxide (yawn) or black powder stuff.

As I'm sure you know, the products of combustion of such mixtures is not an exact science making weights purely theoretical, hence the use of volume.
I actually mixed BaClO4 and BaETSO4 by volume not weight too when making the perchlorate esters (50:50)!

[Edited on 1-9-2004 by Blaster]

Hermes_Trismegistus - 1-9-2004 at 12:34

Quote:
Originally posted by Blaster
As I'm sure you know, the products of combustion of such mixtures is not an exact science making weights purely theoretical, hence the use of volume.


EH?

Perhaps I am mistaken, but I am labouring under the impression that the study of the combustion products would be an exact science, if it were done using the scientific method (and exact weights and measures).

Al Powder

MadHatter - 1-9-2004 at 13:36

Blaster, out of curiosity, what was the mesh and/or micron size of your
Al powder ? I'm curious because I like making my own Al powder for various
flash and rocket mixes.

Blaster - 1-9-2004 at 13:37

Not so! Mixtures such as this produce a multitude of products because of the way the powder is mixed. Whole scientific papers have been written on the products of combustion of black powder.

It is physically impossible to ensure, for example, that one molecule of KMnO4 is adjacent to an Al atom or an S2 molecule. No matter how fine it is ground there will always be accumulations of the various components.

Additionally, and as a direct consequence of this, multiple oxidation states of the manganese and sulphur are produced dependant on how and with what they react. This I have observed in a simple way by setting the mixture off on snow - purple unreacted KMnO4 stains the snow, along with green K2MnO4, fully reduced black MnO2 and others. Similarly SO2 is produced and H2S (it can be smelt despite hydrogen not being theoretically in the mixture as mentioned by Sylla). This is not to mention other products such as MnSO4, Al2(SO4)3, Al2S3, O2, Al2O3, K2SO4 etc, etc. Look at the cloud of smoke - a brown mass of who knows what!

Therefore it is impossible to exactly determine the quantities of reactant required. The best that can be done is an approximation.

[Edited on 1-9-2004 by Blaster]

Blaster - 1-9-2004 at 13:49

MadHatter - I've just checked my bottle of Al powder (its ancient) and it does not quote the mesh size.
It has the consistency of flour however.

If anyone has a method of preparation of extremely fine powder like this (where individual grains are too small to be seen by eye) I'd be very interested to hear it.

vulture - 2-9-2004 at 01:16

I'll guess I'll leave this one open since it's still on a chemistry tangent.

Although this KMnO4/Al/S flashpowder is nothing new, was my first flashpowder that I made in fact.

Do keep it away from water or oxidizable solvents (including acetone) though! :o

KMnO4 + 50 micron Mg is yet another story...:D

Dodoman - 2-9-2004 at 10:15

I've tried this flash before it was not so succesful as i didn't grind the ingredients. This method for preparing flash powder remindes me of my method for preparing black powder. You'll find the post in the Detritus section. BTW love the Porsche. Is it your's.......?

Nice Porsche

Turel - 2-9-2004 at 11:59

Love the car.

JohnWW - 2-9-2004 at 14:08

I would have thought that powdered Mg would make a good flash powder, or component of same. It is more easily ignitable than Al.

John E.

Blaster - 2-9-2004 at 14:52

Dodoman - you didn't grind the ingredients?!!! Tut, tut, the number one rule of firework preparation is fine grinding.

Car - thanks but its off topic!

JohnWW - Mg does make a good flash powder its true. However, I have never come across Mg powder that is as fine as the Al powder commercially available (perhaps its too reactive to be stored and sold when extremely fine) and consequently the burn speed cannot match the Al variant.
Ignition is definately not a problem with the Al mixture with a permanganate oxidant! However, if potassium dichromate is used instead, ignition is difficult and that's where Mg comes into its own.

As an aside - try adding lumps of calcium metal to the mixture for red jets.

[Edited on 2-9-2004 by Blaster]

mg powder

monsterclyde - 3-9-2004 at 05:00

If you played with high powered rockets you would have 1000 mesh mg amongst your supplies works great in place of aluminium powder.

Dodoman - 3-9-2004 at 12:14

Quote:
Originally posted by Blaster
Tut, tut, the number one rule of firework preparation is fine grinding.


[Edited on 2-9-2004 by Blaster]


I know that Blaster. Well anyway i wanted to give it another go so this time i used your method. It burns very slowly in fire and when ignited with glycerine; it first burns after 15 sec with a stedy slow flam. Then suddenly "poof" you get the result in the pic, without the porsche of course.
This is turning into a practical disscution. I'm imagining Vulture saing CLOSED AND MOVED. :P

vulture - 3-9-2004 at 12:39

Quote:

This is turning into a practical disscution. I'm imagining Vulture saing CLOSED AND MOVED.


It is, so don't push your luck. Currently I'm a sleeping dog in the corner, but don't wake me up by straying too much from the dinner table, ok?

On topic:

As KMnO4/Al/S + water is suicide, I used to use acetone to provide more safe and intimate mixing.

Safe I thought...the stuff heats up to about 50C with acetone! I've abandoned this method(DUH!), yet I still am looking for an explanation why this happens.

[Edited on 3-9-2004 by vulture]

chemoleo - 3-9-2004 at 13:04

So are you saying, a drop of water works just as well as glycerine?
Now shouldn't that be added to the 'Interesting reactions' thread?

Blaster - 3-9-2004 at 14:07

Quote:

It burns very slowly in fire and when ignited with glycerine; it first burns after 15 sec with a stedy slow flam


I cannot agree with this - the instant it is ignited it burns with such ferocity it blows whatever I ignite it with out - even my brazing torch!
With glycerine there is a "fizzing" at first but no flame until the flash.

I just added a drop of water to the mixture this minute - absolutely nothing. I then added more and ended up with a puddle of purple water!

Ok, I appreciate this thread is on a knife edge so to move it away can anyone suggest the oxidation pathway of the glycerine?

[Edited on 3-9-2004 by Blaster]

Blaster - 4-9-2004 at 05:02

I've now tried several ignition substances for this flash powder.

Ethanol and propan-2-ol do not cause ignition. There is evidence of a reaction but it doesn't get hot enough to ignite.

Ethylene glycol does ignite the mixture but unlike glycerine there is no "fizzing", just a flash after around 10 seconds.

Conc H2SO4 causes instant flash presumably due to the formation of the very unstable permanganic anhydride.

My guess with glycerine is that full oxidation to:
occurs.

Dodoman - 4-9-2004 at 05:47

It burns as i said before. I don't have a digital cam or a scaner so you'll have to take my word for it. Maybe i screwed it up again :(. It burns very slowly with a flame i suspect the mixture to contain too much KMnO4. Though i did use the volume method you mentioned.

Michal - 4-9-2004 at 06:36

Quote:
Originally posted by Blaster

Conc H2SO4 causes instant flash presumably due to the formation of the very unstable permanganic anhydride.


Hmmm, wouldn't it be a stupid idea to use Sulfur with KMnO4 ? On contact with moisture it could form a small amount of H2SO4, just like that its a very bad idee to add sulfur to a chlorate because ClO2 is formed witch can self ignite at high concentration.

Holy CRAP!!!

rift valley - 4-9-2004 at 09:13

I just made a little over a gram of conventional flash powder and ignited about .3 of a gram of it unenclosed. It sounded like a rifle shot!!! It scared the living shit out of me and my mother luckily she is understanding and none of the neighbors called the police. This is the end of the line for energetic materials for me. If this is an LE I can't imagine what an HE is like. O well I guess I have 2 pounds of 3 micron Al that is destined for use in thermites.

(I am sorry if this is off topic but I thought it would be a good warning as to how loud this stuff really is!)

ordenblitz - 4-9-2004 at 10:13

Quote
-------------------------------------------------------------------------------------------------------
Therefore it is impossible to exactly determine the quantities of reactant required. The best that can be done is an approximation.
-------------------------------------------------------------------------------------------------------

IMHO it's more correct to say, "it is impossible to determine the products of combustion" then the reactants required.
I make theatrical pyrotechnics for a living, and I can assure you one thing I make sure of is the exact quantities and quality of my reactants!

Quote
-------------------------------------------------------------------------------------------------------
Mg does make a good flash powder its true. However, I have never come across Mg powder that is as fine as the Al powder commercially available (perhaps its too reactive to be stored and sold when extremely fine) and consequently the burn speed cannot match the Al variant.
-------------------------------------------------------------------------------------------------------

1-11 micron spheriodal magnesium is used quite regularly in pyrotechnics. I get it directly from the manufacturer but I think Skylighter and Firefox sell it. It is amazingly powerful in combination with strontium, barium or sodium nitrate. Mixtures of sodium nitrate and 1-11 mag in quantities of more than about 5 grams will progress to near detonation velocities if ignited unconfined.
I wouldn't even think about combining it with more powerful oxidizers such as perchlorates or chlorates.

fvcked - 4-9-2004 at 17:44

I dont think it would be wise to mix nitrates with Mg. Unless you coat the Mg in linseed oil. The nitrates and Mg react and may cause ignition.

Sorry if this is too far from the table vulture, I dont like to wake dogs:)

Flash

MadHatter - 5-9-2004 at 08:08

Rift valley, by conventional, do you mean 3 micron Al with KClO4 ?

JohnWW - 5-9-2004 at 18:51

Oxomalonic acid, which Blaster thinks he made, exists (see Google). If it is stable enough to be dehydrated, its dimeric cyclic anhydride, with the formula C6O8, would be another carbon oxide. However, the anhydride does not show up on Google. I brought up the subject of carbon oxides in another organic thrread recently.

John W.

Blaster - 6-9-2004 at 02:39

Quote:

Hmmm, wouldn't it be a stupid idea to use Sulfur with KMnO4 ? On contact with moisture it could form a small amount of H2SO4, just like that its a very bad idee to add sulfur to a chlorate because ClO2 is formed witch can self ignite at high concentration.


This is rubbish! Elemental sulphur will not react this way with either oxidant mentioned.


Conversely, an excellent reply by ordenblitz. I agree with all you say.
If I was in the trade I would of course use weight for consistency and greater accuracy, especially with large quantities. Being a purely amateur firework experimenter however, volume has proved more than sufficient for me.

The fact that Mg can be obtained so fine is something new to me. Unfortunately, I am restricted to commercial laboratory grades. Being in "Nanny State" Britain, I imagine purchase of the above powders from a pyrotechnic supplier will prove impossible but I'll look into it.

Oxomalonic acid was a pure guess - I was hoping an organic chemist in the forum could help me out there!

BromicAcid - 6-9-2004 at 06:27

When I was into pyrotechnics I heard to never mix sulfur with chlorates over and over again. The theory is that commercial grade sulfur contains impurities that can cause the mix to become acidic on standing which can lead to the decomposition of the sensitive chlorate molecule which can lead to the catalyzed spectacular decomposition of the mix. Doing an Internet search brought up several pages supporting this theory.

However high grade sulfur that lacks this acid component can be somewhat safely mixed and stored with chlorates (although it is recommended to add a component that is basic, barium carbonate or other coloring agent to negate possible acid formation). Sulfur mixes with chlorates are sensitive regardless of this.

Back onto permanganates, the spontaneous ignition of this mixture upon the addition of glycerin makes total sense. Permanganate is a strong oxidizing agent and once the oxidation starts it heats up and it won't be able to stop at any stage in between, it will heat itself as it oxidizes and by then you have a hot acidic soup laying on top of a pile of strong oxidizer mixed with combustible (strong oxidizer that doesn't like the acid much anyway).

Doing a google in the groups section, particularly in rec.pyrotechnics for the properties of potassium permanganate mixtures gives many warnings and long threads on the subjet.

vulture - 6-9-2004 at 08:13

I don't see why potassium permanganate shouldn't be able to oxidize S in humid condition to H2SO3 or even H2SO4.

If you think this is rubbish, please provide some reference.

ordenblitz - 6-9-2004 at 09:41

Bromic,

The problem with sulfur and chlorates is two fold. Early in the past century before the advent of vulcanized rubber for tires, obtaining sulfur free from acid residue was more difficult making the possibility of a pyrophoric mixture "acid+chlorate" more possible.

S+xCLO3 results in a mixture that is very friction and impact sensitive even when free from residual acidity. Many budding pyros, including myself some 30 years ago, have heard the snapping and popping while mixing the two by mortar and pestle. Some were not as lucky to be given a warning.

Blaster - 6-9-2004 at 12:21

Ok, firstly the likelihood of sulphur being oxidised at room temperature by the KMnO4 is very small given that the reaction of pure O2 and sulphur to form SO2 does not occur below 260’C and the formation of SO2 from MnO2 and sulphur also requires a high temperature ie. SO2 has a high enthalpy of formation from its elements.
I appreciate that these are not aqueous solution examples but I’m unable to find a specific reference with permanganates. It could be calculated with heats of formation I have no doubt.
Disregarding this, even assuming that SO2 could be formed with consequent production of H2SO3 or H2SO4, the reaction would result in the formation of K2SO4 + MnSO4 under acidic aqueous conditions (Chemical Elements and their Compounds, Sidgewick Vol II p.1269).
Permanganic anhydride is very endothermic, requiring both strong oxidising AND dehyrating conditions for its formation. These conditions could not be met in a moist atmosphere. It’s a similar story for the chlorate and sulphur mix.
The presence of impurities forming acids that Bromic quoted is interesting. Without specific details I cannot comment on this but I’m guessing that moisture is not a prerequisite.

That’s a brief theory, here’s my experience in practice. I have prepared chlorate based black powder (no nitrate at all in the mix) which I use for underwater fuses and kept it in a damp garage for several years – unsealed because of the risk of friction ignition (I agree once again with ordenblitz here). There is no evidence of degradation. If water is added in any quantity there is no reaction even on standing. Same again for the flash powder, although this does deteriorate due to oxidation of the Al powder over time.

Has anyone tried red phosphorus and KClO3, or better still dissolving yellow phosphorous in CS2 and allowing the solvent to evaporate after pouring it on KClO3, now that IS a dangerous mix!

[Edited on 6-9-2004 by Blaster]

chemoleo - 6-9-2004 at 14:11

On this issue, did you even note that sulphur smells??? It doesn't smell of H2S, no, it smells of SO2. Just take a whiff at your S- jar, and you will notice it too.
For all practical purposes, S does naturally contain a small amount of SO2 (unless, say, you were to melt and crush it right before use, under argon/N2 atmosphere)

neutrino - 6-9-2004 at 15:00

Quote:
Originally posted by Blaster
Ok, firstly the likelihood of sulphur being oxidised at room temperature by the KMnO4 is very small given that the reaction of pure O2 and sulphur to form SO2 does not occur below 260’C and the formation of SO2 from MnO2 and sulphur also requires a high temperature ie. SO2 has a high enthalpy of formation from its elements.




This isn't meant as a flame, but maybe I should correct a few things here. In order to ignite, only traces of acid have to be present. The reaction of O<sub>2</sub> with S to form SO<sub>2</sub> and SO<sub>3</sub> is exothermic (very low enthlapy), and , if I did the math correctly, will always happen in small amounts above absolute zero. The reaction with oxygen may be slow because O<sub>2</sub> is a weak oxidizer, but it will happen much faster with a stronger oxidizer like KMnO<sub>4</sub> (where the two chems touch). To get an idea of how powerful KMnO<sub>4</sub> is, think about this: keratin will not be oxidized by oxygen very quickly (if at all), but if KMnO<sub>4</sub> is added, it will be almost instantaneous. That's what happens when you spill a KMnO<sub>4</sub> solution on your skin.

Blaster - 6-9-2004 at 15:22

My mistake re: enthalpy of formation - I should really have said activation enthalpy.

fvcked - 6-9-2004 at 15:55

Ordenblitz said:
Quote:
Many budding pyros, including myself some 30 years ago, have heard the snapping and popping while mixing the two by mortar and pestle.


Now thats a dumb thing to do! I sure hope you dont do that anymore. You will lose a hand or your face if you do. Never grind or roughly mix any flash comp.

(again sorry vulture if this is straying too far, but I thought it pertinant to add a safety warning)

[Edited on 6-9-2004 by fvcked]

ordenblitz - 6-9-2004 at 17:49

Blaster said:
Quote
--------------------------------------------------
Has anyone tried red phosphorus and KClO3,
--------------------------------------------------

I believe this combination is known as Armstrongs Mixture. It's sensitivity to impact, friction and just about anything else including dirty looks is only slightly better than NI3.

(But as Bromic has pointed out this was his intended point )

Fvcked said:
Quote
--------------------------------------------------
Now thats a dumb thing to do!
I sure hope you don't do that anymore.
--------------------------------------------------

Thanks for your concern fvcked, but I believe I mentioned that my sulfur/chlorate incident happened some 30 years ago. I was about 11 years old. I'm fairly certain all of us at one time or another have done some pretty stupid things especially in our youth. These mistakes and certainly our successes do shape our lives and sometimes our futures. My younger days cemented my love of pyrotechnics and chemistry such that it was my only logical career choice and has been for the last 18 years.

I was especially amused by your warning about magnesium in combination with nitrate oxidizers. You might be surprised to know that 95% of all indoor theatrical pyrotechnics are combinations of the above. Strontium nitrate with magnesium being the most useful for airbursts, flash pots, concussion and a myriad of other amusing effects.

Regarding that earlier post… Linseed oil fell out of favor in the 50's as a protective coating for magnesium. Typically the only time Mg needs passivation is when used with ammomium perchlorate. Potassium dichromate is employed for the conversion coating for that purpose.

[Edited on 7-9-2004 by ordenblitz]

BromicAcid - 6-9-2004 at 17:58

Quote:

I believe this combination is known as Armstrongs Mixture. It's sensitivity to impact, friction and just about anything else including dirty looks is only slightly better than NI3.


He was just saying that to prove there are more dangerous mixes out there, expecially when he suggested a saturated solution of white phosphorus in carbon disulfide poured onto chlorate.

Blaster - 7-9-2004 at 00:48

Just to add a final bit of weight to my above theory, I mentioned I'd added water to chlorate black powder and the flash powder with no reaction. I've now tried the same with boiling water and again nothing for both mixtures. Then I tried adding 10% H2SO4 to both - still nothing, and finally boiling 10% H2SO4 and even then nothing. I rest my case for the moisture theory!


Odenblitz I once again agree with what you say - the risky things I have done in my time and still do to a certain extent 20 years on (eg. ethyl perchlorate) would make most people shudder. I happen to enjoy it!
An example when I was a kid with the red P/KClO3 mix - I mixed it with a stick on the floor and then rode my bike over it - I was blown a foot into the air!

Great choice of career btw, any vacancies? I have lots of experience!!!

fvcked - 7-9-2004 at 14:55

ordenblitz said:
Quote:

I was especially amused by your warning about magnesium in combination with nitrate oxidizers. You might be surprised to know that 95% of all indoor theatrical pyrotechnics are combinations of the above. Strontium nitrate with magnesium being the most useful for airbursts, flash pots, concussion and a myriad of other amusing effects.


The Mg reduces the nitrate and forms other chemicals that I dont care to go into right now, but they do make the mixture heat up and/or self ignite on rare occasions. And as for you saying that "everyone uses it", well many people use AP, and thats not safe. I am sure someone can elaborate for me on the reaction but as for now, im going to sleep.

vulture - 8-9-2004 at 05:25

Nitrates + Al + moisture ----> alkaliamines, which are strong bases and react exothermically with aluminium.

Armstrong's mixture

MadHatter - 8-9-2004 at 10:18

Rift valley, I couldn't help but laugh about your post with conventional flash.
I also think your Mom is as cool as mine was when I was growing up !
It's been over 30 years since I blew my eyebrows off while making
Armstrong's mixture. All my mother could do was laugh her ass off upon
seeing me without my eyebrows ! The only other thing she said is
"YOU'LL LEARN !". Funny thing is that my stepfather was a narc in the
U.S. Coast Guard and didn't mind me making my own shit ! I pissed him
off every time my friends and I would sneak over the border into Canada
to get the highly illegal fireworks that were banned in Maine ! And only
because Maine said they were illegal ! It's nice to have supportive parents
but don't push your luck. Even parents with a more liberal attitude
towards your "research" have their limits. Enjoy your youth but don't
kill yourself in the process, and always make sure you have lots of fun !

chemoleo - 9-9-2004 at 09:08

Quote:

Nitrates + Al + moisture ----> alkaliamines, which are strong bases and react exothermically with aluminium.


Vulture, I don't follow this. Could you elaborate?
Are you saying that NaNO3 is converted to NaNH2 this way??? which in the presence of moisture of course immediately forms NH3 and NaOH? So really what reacts is the NaOH, forming aluminate? A direct conversion to NaNH2 sounds unlikely to me though (simply becuase it is so highly reactive), even if the NaNH2 is only an intermediary.... comments?

The_Davster - 4-12-2005 at 14:30

Blaster had mentioned white P and chlorate, I have a chemistry demonstartion book that makes mention of this( and I got it at chapters only a year ago, with actually interesting demonstrations in it....how rare is that:o)

Quote from book:
"You place a few drops of a solution of yellow phosphorus in carbon disulfide on a 5 grain tablet of KClO3 which is resting on the base of a rignstand. In 15 minutes the solvent will have evaporated and the tablet is ready to be exploded. Touched with a metal rod from a ringstand, the explosion is violent"

I am rather surprised that it does not just spontaneously explode once the CS2 has evaporated....

Also, in keeping with this threads topic of unconventional flash powders, I just tried sodium peroxide-nonahydrate(self made) with Mg filings, aprox 1:1 by volume(I know not reliable). The burn rate was not incredibly fast, about the same as decent BP, but was incredibly bright, I had blind spots despite wearing UV goggles(nothing has ever caused this before when wearing these goggles)

Fleaker - 9-12-2005 at 18:08

That would be the oxygen developed by the Na2O2 reacting with the magnesium and burning with that high intensity flame. There was no characteristic yellow color to the mix then?

It is hard to make a fast sodium peroxide mixture since the material is very hygroscopic and quite tough to grind.

The_Davster - 9-12-2005 at 18:57

Oh the flame was yellow, the brightest sodium orange I have ever experianced.:)

The sodium peroxide was also not ground well, just crushed with the metal spatula, after taking it out of its vial. My sodium peroxide is not in large granules, it is rather fine crystals. I followed the procedure Polverone got from the inorganic synthesis books,(there is a thread somewhere here on that), but unfortuantly I spent my time searching for that synth in the inorganic synthesis volumes at the library, before checking the forum(and the inorganic synthesis volumes lack any real indexing method, that I know of). I also only dried it over CaCl2 for a week, not concentrated sulfuric, and only used half the recomended ammount of etOH they suggested for washing.

Also I have been unsuccessful in doing the sodium peroxide/kleenex hypergol, but likely because I was only working on a small scale.

EDIT: I never really experianced much hygroscopicity, even after leaving a small pile in an open beaker overnight, but by the next day it had likely become sodium carbonate as the peroxide reacts with the CO2 in air. I should test that...and I will go leave a bit out right now!

[Edited on 10-12-2005 by rogue chemist]

stygian - 9-12-2005 at 19:03

Anybody notice that according to brauer, potassium aurate is said to decompose to something like Au, K2O and KO2? If there was an easy way to separate these, potassium superoxide would be fun to play with :)

Fleaker - 9-12-2005 at 19:30

Fun perhaps, but expensive too! At $510 an ounce for gold, it would easily be one of the most expensive ways to get potassium oxides. Then again, you do get your gold back too :-)

DeAdFX - 9-12-2005 at 21:27

For my flash I use Potassium Permanganate and Aluminum. My Aluminum is 8 mesh. I am thinking of using this mixture as a rocket fuel igniter as it burns "slower" compared against other finer aluminum/magnesium.

Anyways I never bother with the sulfur addition as it makes a fairly nasty smell.


[Edited on 10-12-2005 by DeAdFX]

neutrino - 10-12-2005 at 05:56

8 Mesh? That's very coarse for flash powder.

ordenblitz - 10-12-2005 at 08:22

Powder... that's more like gravel.

[Edited on 10-12-2005 by ordenblitz]

PHILOU Zrealone - 19-12-2005 at 10:41

If H2S smell evolved from contact with snow...it was simply because Al2S3 that forms upon reaction between Al and S2 decompose upon contact with water...and snow is water. So the hydrogen is exogen!

Al + S --> Al2S3
Al2S3 + 3H2O --> Al(OH)3 + H2S(g)

Glycerin will oxydise in many ways upon contact with KMnO4...
CH2OH-CHOH-CH2OH --> CH2OH-CHOH-CH=O --> CH2OH-CHOH-CO2H

CH2OH-CHOH-CH2OH --> CH2OH-CO-CH2OH --> CH2OH-CO-CH=O -> CH2OH-CO-CO2H --> CH2OH-CH=O + CO2

CH2OH-CHOH-CH2OH --> CH2=CH-CH=O + 2H2O

etc etc etc...any combination of ceton, aldehyd acid oxydation
Until oxalic acid and subsequent oxydation into CO2 and H2O!

Simple alcools doesn't work good because if they react, their decomposition products and the initial alcool are too volatile to keep the heat of reaction undissiped...by boiling off they take the heat.
Heat/Temperature is a crutial aspect because glycerin/KMnO4 is strongly dependant on it.
Any factor that can increase heat confinement will help...
-larger amounts (No I don't invite you to try :mad:!)
-viscous water soluble compound (suggar shoud work and will be oxydised upon time by moisture from the air...so storage is inadvisable!).Any organic acid, ceton, alcool, aldehyd will make it!
Glycol works faster than glycerine because it dissolves faster KMnO4, Glycerol being more viscous need to reach a slightly higher temperature to perform the same result.
-High boiling point or decomposition point organic reducing compound soluble in water.
-The specific surface of KMnO4... the smoother the faster the dissolution occurs and the faster the heat release.
-adiabatic container (sealed and insulated)...Never try...will explode but when!
In such a container ethanol and isopropanol will make the same job as glycerin!
-Higher initial temperature...

Always ratio by weight... volume change too much to get something scientifically reliable en reproductible.

Water takes so much heat away that if above a certain amount it will overflow the heat realease... So a tiny percentage should be tried to give a scientific answer to the moisture problem.

Any trace of acid generated by the sulfur will take the protection layer of the Al (passivation oxyd layer) away and make the mix more reactive...this is what happens precisely when adding S to the Al/KMnO4 mix...(the later is harder to ignite).So catalytic effect from S is due to SO2 and SO3 with water...SO2 in KMnO4 generates H2SO4 as SO3 with water...
The water comes from the oxydised glycerin...

The fact dry suggar doesn't react fast with the mix prooves the importance of water in the proces ...but be carreful... once the oxydation of suggar is started the amount of water generated will accelerate the reaction to runnaway...and ignition (if amount of composition is sufficient).

Example of KMnO4 oxydiser with skin is also a bit tricky...since skin doesn't do much on its own but sweating wel...it is the dissolved KMnO4 that reacts with the proteins of skin.

My guess about the yellow P and chlorate is that it is on the edge between white and red....and so it may remain relatively stable in cold O2.

When Vulture says:
Al + NO3(-) -H2O-> NH3 + Al(OH)3...he is right...
Same happens with Zn and any metal that can reduce NO3 to Ammonia...
The resulting NH3 and generated base ... NaNO3 will generate NaOH... will dissolve the passivation oxyd layer of Al and increase its reactivity towards oxydants.

[Edited on 19-12-2005 by PHILOU Zrealone]

Blaster, nice pictures!

kABOOM! - 20-12-2005 at 00:28

Hey, flash powder got me started in pyrotechnics... ever since that day I made KNO3/Al/S flash powder. It was slow, flaring up rather than making that "poof" so characteristic of traditional powder but it did the job. Your KMNO4+Al+S flash composition looks very good...
You measured by volume, right? Not by weight? curious...maybe I misread your post.

pyrochem - 1-1-2006 at 15:05

Quote:
Originally posted by stygian
Anybody notice that according to brauer, potassium aurate is said to decompose to something like Au, K2O and KO2? If there was an easy way to separate these, potassium superoxide would be fun to play with :)


KO2 is the main oxide formed on K metal when it burns, so it is not that hard to make.

As for flash powder, I used sodium persulfate as the oxidizer. I mixed it with fine Al powder. When lit, it flashed brightly with a poof. I will try confining it next. The reaction is probably:
Na2O8S2 + 4Al => Na2S + SO2 + 2Al2O3

I am a bit concerned with its stability. Does anyone know if persulfate will react with Al at room temperature?

An electronics website suggested using aluminum to remove Cu and persulfate from etching solution (which is sodium or ammonium persulfate). The website said the reaction would be catalyzed by chloride. However, when I mixed aluminum powder and sodium persulfate in solution and added sodium chloride, I had no visible reaction or heat production.

KMNO4/Al/S Flash powder test.

kABOOM! - 16-3-2006 at 20:42

This is approx. 1/2 cup of 325 mesh Aluminum-Sulfur-Permanganate flash powder. I really enjoyed the luminous fireball it produced. The video posted does have audio.


[Edited on 17-3-2006 by kABOOM!]

Attachment: MVI_0718.mp4 (824kB)
This file has been downloaded 2009 times


DeAdFX - 9-4-2006 at 15:29

Quote:
Originally posted by Blaster

By volume: potassium permanganate 2 parts, Aluminium powder (the finest flour-like grade) 1 part, powdered sulphur 0.5 part.


This composition will burn much faster and hotter than black powder and is vastly superior for making cannon crackers or any firework requiring an explosive charge. It explodes without fail when confined in any way (if prepared as above).

However this composition has an even better property, namely it can be ignited by adding a drop of glycerine. This reacts with the KMnO4 and gets so hot it ignites the mixture.
The mixture usually takes around 20 seconds to ignite depending on ambient temperature.

This is great for setting off a sequence of explosions without using a flame - simply add a drop of glycerine to each charge.




I have recently purchased some 1000mesh Aluminum (14microns) and I am interested in making some flash powder. I am curious, is the Sulfur necessary for the flash powder to ignite reliably with the hypergolic ignition? I personnally dislike using sulfur in my pyrotechnic compositions.

kABOOM! - 13-4-2006 at 23:59

Yes! With Aluminum powder and Potassium Permanganate, Sulfur is a must. I've tried a mix of Al/KMnO4 and I just recieved some white hot sparks and flaring but no "poof". Sulfur acts as a catalyst and speeds up the reaction and makes ignition much easier**

Al/KMnO4/S is a VERY STRONG flash powder and is close to Al/KClO4 flash mixture in terms of power, but a heck of a lot more sensitive to shock and friction. I tested 1 lb canister of Permangante Flash Powder sealed with an electric match, and the explosion was INSAIN. It destroyed a mid sized armored safe without hassle- blew the doors right off it and warped the frame.

waxman - 30-5-2006 at 16:31

Hey kaBOOM- some would say making a pound of flash is also "INSAIN"!
I'm trying an ounce or two.

woelen - 31-5-2006 at 00:30

His name is kABOOM! and there is a good reason for that :D.

Zinc - 5-6-2006 at 09:34

Would KBrO3/Al burn faster or slower than KClO3/Al?
If faster how much faster and if slower how much slower?

Blaster, nice pictures !

CycloKnight - 10-6-2006 at 14:56

I recently made up a small batch of this powder, and I'm quite impressed with the results :o.
The moment it ignited there was an instant blinding "POOF!".
Had to rely on peripheral vision for a few minutes..lol

The first time I made this mixture was back in the early 1990's as a young teenager, and when I made it, it only flared, this was because I couldn't get fine mesh Al powder. I'd made the powdered Al using a piece of Al and a file...
IIrc I first learnt of the formula from Kurt Saxon's book "The Weaponeer"

I'm just curious, what is the general consensus as to the safety of this composition? Especially with regards to the presence of both sulfur & permanganate in this composition?
Would adding a small percentage of carbonate make it safer by neutralising any moisture induced sulfurous acid that could form?
Or is it simply best to make the composition and use it ASAP?

Has anyone had an experience with increased sensitivity of this material after storage (i.e. few weeks/months)?

ethan_c - 12-6-2006 at 00:34

Quote:
Originally posted by CycloKnight
I'm just curious, what is the general consensus as to the safety of this composition? Especially with regards to the presence of both sulfur & permanganate in this composition?
Would adding a small percentage of carbonate make it safer by neutralising any moisture induced sulfurous acid that could form?
Or is it simply best to make the composition and use it ASAP?

Has anyone had an experience with increased sensitivity of this material after storage (i.e. few weeks/months)?


Just treat it like any sulfur/permanganate flash powder. Best to make it and use immediately, or if absolutely necessary store in a desiccator/polybag/something that will block moisture from getting to it. And if you're not complete sure of the purity and cleanliness of the sulfur, don't even try to store it. I found out the hard way that questionable sulfur can indeed do you (and whatever it's being stored in, and whatever is around) quite wrong.

That said, it seems (in my experience) to be pretty safe to manipulate and handle in the short term just after mixing it up. Go nuts.

I2O5/Al

Zinc - 13-6-2006 at 10:55

Could a mixture of I2O5 and Al powder be used as a flash powder or would it be to unstable to use?

The advantage of I2O5 is that the whole molecule would be used instead of just a part of the molecule as with most common oxidisers.
The equation would be:
3I2O5+12Al---10Al2O3+2AlI3

DeAdFX - 13-6-2006 at 13:38

It could be used only if the I2O5 is kept completly anhydrous. Otherwise the I2O5 will form iodic acid(correct name?) which will then react with the aluminum.

Canuck - 13-6-2006 at 19:39

Quote:
Originally posted by ethan_c
Quote:
Originally posted by CycloKnight
I'm just curious, what is the general consensus as to the safety of this composition? Especially with regards to the presence of both sulfur & permanganate in this composition?
Would adding a small percentage of carbonate make it safer by neutralising any moisture induced sulfurous acid that could form?
Or is it simply best to make the composition and use it ASAP?

Has anyone had an experience with increased sensitivity of this material after storage (i.e. few weeks/months)?



Just treat it like any sulfur/permanganate flash powder. Best to make it and use immediately, or if absolutely necessary store in a desiccator/polybag/something that will block moisture from getting to it. And if you're not complete sure of the purity and cleanliness of the sulfur, don't even try to store it. I found out the hard way that questionable sulfur can indeed do you (and whatever it's being stored in, and whatever is around) quite wrong.

That said, it seems (in my experience) to be pretty safe to manipulate and handle in the short term just after mixing it up. Go nuts.


I'll second this.. I have stored it up to 1 month in a dark dry climate controlled box. I would not consider storing it anywhere else as it is too dangerous. If humidity is present during storage consider it a ticking time bomb. DO NOT STORE IT FOR EXTENDED PERIODS OF TIME !!!:o

K2Cr2O7/Al

Zinc - 12-7-2006 at 04:03

Would a mixture of K2Cr2O7 and Al be useful as a flash powder or would it be to unstable to use? Also would be adding sulfur to the mixture be a good idea?

DeAdFX - 12-7-2006 at 04:13

I don't think their would be any severe stability issues with that mix. Potassium Dichromate is used to stabalize Magnesium by adding some sort of coating to it. Just make sure the mixture stays anhydrous others the Magnesium will lose its "power". I have no clue how sulfur would influence the mix but Potassium Dichromate is a pretty potent oxidizer. You might be better off excluding it.

YT2095 - 12-7-2006 at 04:36

it`s also quite toxic for use in flash powder compared to KMnO4.

neutrino - 12-7-2006 at 07:55

Not so much toxic as carcinogenic. I would really advise looking for another oxidizer.

Zinc - 12-7-2006 at 08:35

Quote:
Originally posted by neutrino
I would really advise looking for another oxidizer.


How about KBrO3?

YT2095 - 12-7-2006 at 12:10

Bromate`s good, although a little sensitive (esp with RP).

Zinc - 12-7-2006 at 12:33

Be careful bromates are carcinogenic. http://en.wikipedia.org/wiki/Bromate

gregxy - 12-7-2006 at 16:55

How about adding a small amount potassium carbonate to flash powder mixtures that contain sulphur. This could neutralize the acid and slow down the self decomposition.

I have an old book that talks about primers that used to contain chlorate and sulphur. On long storage they would become inert due to the sulphur forming H2SO4. They mentioned using something like this to stabilize them.

Zinc - 13-7-2006 at 13:19

2 hours ago I ignited a small amount of the KMnO4/S/Fe flash powder. It was really impressive. A bright flash and a lot of sparks.

quicksilver - 14-7-2006 at 06:42

As long as we are on this subject I would like to add a little "FLASH POWDER TRIVIA"... The original pressure fuze used in Civil War landmines (which werre the first landmines used by the United States were initiated by something called the "Rains Fuze" which at that time was a Confederate top secret. It was composed of 50% KCLO3 30%, Sb2S3, 20% powdered glass. In was named after BRg-General Gabrial J. Rains who was in charge of the Confederate landmine production. He also lost his 1st finger and thumb of his right hand to a pressure fuze design using more sensitive flash comp. These were utilized in what at that time were called "torpedoes" made of BP encased in iron. And thus starting a landmine race with the North. Both side considered it vary barbaric and cowardly. The use of BP when properly encased was very, VERY effective. The ultinate landmine of the Civil War however was a flash comp of KCLO3, S, chalk, willow charcoal, & PbO. This was used as a large charge to "disturb or destroy horse drawn cannon" (the first AM mine!).
I have a wonderful collection of papers that I am scanning to upload to the FTP as one big PDF file exclusivly on the use of low explosives in war from the Middle Ages to VietNam. Low explosives have been used very remarkably when properly enclosed as anti-personnel & material explos for hunderds of years. Interestingly the major accidents have all occured during the making of proper fuzes, mostly pressure devices using flash.

{That's "fuze" not fuse!}

Zinc - 14-7-2006 at 08:21

A few hours ago my friend and I ignited a small amount of the KMnO4/S/Zn flash powder. It burned slow (for a flash powder). I think it burned slow because the zinc was very coarse. Most particles of zinc were about 0.7-1 mm long.

[Edited on 14-7-2006 by Zinc]

scientistfromdarkness - 3-10-2006 at 12:16

KO2 does not exist !!!!

The_Davster - 3-10-2006 at 20:25

Then whats the nasty stuff on my potassium:P

It exists, check any university level inorganic textbook, or google potassium superoxide.

scientistfromdarkness - 4-10-2006 at 00:43

nasty stuff on your potassium can also be KOH or K2CO3...

12AX7 - 4-10-2006 at 13:55

Quote:
Originally posted by scientistfromdarkness
KO2 does not exist !!!!


Well then as long as we're denying the existence of things, I say you do not exist, and therefore KO2 does exist.

Tim

woelen - 4-10-2006 at 14:10

KO2 really does exist. It is called potassium superoxide, the relevant ion is O2(-) and that ion is fairly stable, when combined with large cations, such as K(+), Rb(+) and Cs(+).

For really large cations, even the ozonide ion is stabilized. This is O3(-) and compounds like CsO3 even exist.

Jdurg - 6-10-2006 at 10:09

I will concur with what others have already said here. KO2 most certainly does exist. What I need to do is go and get my potassium lump photographed to try and find out what the deep, blood red metallic-like oxide coating is. Potassium Peroxide and Potassium Superoxide are a yellow-orange color so I believe that this deep red oxide (I think) on the surface of my potassium is some type of oxide. I just can't find any reference to any red colored potassium salt and it's driving me nuts.

halogen - 6-10-2006 at 10:50

could be a nitride.

Jdurg - 6-10-2006 at 19:41

Quote:
Originally posted by halogen
could be a nitride.


Possibly, but I wouldn't expect a potassium nitride to form as readily as the red coloring has at room temperature.

Explosive power of flash powder

gregxy - 11-10-2006 at 12:16

Has anyone ever tried to determine the power of self initiated flash powder? For example using the lead block expansion test.

This weekend I wanted to split a large piece of wood (24" dia by 24" long) so I drilled a 0.5" X 4" deep hole in the top filled it with KClO3 based flash and glued in a wood dowel with fuse. The powder split the entire block and blew the top portion into chunks. Pretty impressive. It would be interesting to compare this with a true detonating explosive.

Chris The Great - 11-10-2006 at 22:33

I read a journal on exactly that. I searched my files and found nothing, though. Basically, flashpowder could obtain the blast power of TNT and a fairly decent lead block as well, from what I remember. The author's also destroyed a house using 5kg of it. Somebody probably knows the one I'm talking about and has it.

quicksilver - 12-10-2006 at 07:00

IIRC it's 75% of TNT in terms of LB - HOWEVER I am pretty sure that's not self initiated. It's with a #6. The USBoM did all their stuff with dets. Even Shimezu did his stuff with a detcap (I think it's about 3200mps).
Self initiated experiments are hard to find. The PGII has some stuff out but the experiments deal with sound and issues related to pyrotechnic issues.
The self initiated experiments would have to take into account if any confinment was used and therfore what and howmuch and how to control consistency of confinment. Even a paper tube could vary due to the adheastion of the end caps, etc.
let's say that you design an experiment with 50 grams that would self contain....there you could have a good chance to get a bettr grasp on what it does. But who would want to go to that length? It's not used in industry - so all the testing that has been done with quality equipment would not be available. :(
Remember the LB is of a given volume and that would effect the results when compaired to an HE that doesn't need containment. If you use the 50 gram mark that would put the volume limits of the LB to some subjective interpretation.

Zinc - 18-10-2006 at 11:46

Yesterday I ignited a small amount of a KNO3/S/Mg flash powder.
It burned very fast (dissapeared in a flash).

Could a mixture of (NH4)2Cr2O7 and Al or Mg be used as a flash powder (I know that ammonium dichromate has zero oxygen balance)?
How stable would the mixture be?
Also would be a good idea to include sulfur in the mixture?

Also I have heared that MnO2 is used as a catalyst in chlorate based flash powders and I know that it is true.
How much MnO2 should be added to the 70/30 KClO3/Al flash powder for maximum performance increase?

DeAdFX - 19-10-2006 at 09:03

Quote:
Originally posted by Zinc
Yesterday I ignited a small amount of a KNO3/S/Mg flash powder.
It burned very fast (dissapeared in a flash).

Could a mixture of (NH4)2Cr2O7 and Al or Mg be used as a flash powder (I know that ammonium dichromate has zero oxygen balance)?
How stable would the mixture be?
Also would be a good idea to include sulfur in the mixture?

Also I have heared that MnO2 is used as a catalyst in chlorate based flash powders and I know that it is true.
How much MnO2 should be added to the 70/30 KClO3/Al flash powder for maximum performance increase?


NH4)2Cr2O7 --> N2 + 4H2O + Cr2O3

H2O + metal --> H2 + metal oxide

Cr2O3 + metal --> Cr + metal

Zinc - 27-10-2006 at 11:09

How about Na2S2O8 and Al?
Also would the mixture be stable enough to use and is it a good idea to include sulfur in the mixture?
I would try it my self but I don't have any sodium persulfate.

12AX7 - 27-10-2006 at 16:22

Probably...

Na2SO4 + Al works fine as-is, giving sodium vapor (the mixture is too energetic to be of much use for sodium metal; sodium sulfide or oxide would be a more viable starting point).

...Isn't potassium persulfate the only one reasonably stable? I remember something about sodium and ammonium persulfates being limited on storage.

Tim

Zinc - 29-10-2006 at 05:07

Today I ignited a small amount of the K2Cr2O7/Mg/S flash powder.
It burned very fast.

Zinc - 2-11-2006 at 12:09

Two days ago my friend ignited a small ammount of K2Cr2O7/Al/S flash powder.
It burned very fast but it was harder to ignite it than the K2Cr2O7/Mg/S flash powder.

Zinc - 5-11-2006 at 12:14

How about P2O5/Al?

h0lx - 12-11-2006 at 07:35

I have just made an amount of Ca turnings, going to powder them and try different flash compositions(dangerous, I know, but curiosity killed the cat). Any suggestions of compositions?

Mr. Wizard - 12-11-2006 at 10:02

Ca turnings eh? I had some of those years ago, donated by a helpful school teacher. They are fairly brittle, but I managed to file them into a small pile and mixed them with an equal sized pile of sulfur. I didn't have a scale in those days. The ignition test was a long wooden match and the flash burned my fingernails, leaving a white smoke cloud in the air and me running to the kitchen to cool my fingers under a faucet. It was very energetic and bright. It made a half loud crackling noise, the first time I ever got any noise from an unconfined mixture. I was lucky I only had a small amount of Ca turnings!!

Edit- The Flash from the Ca / S mixture was a RED flash. I forgot until the mention of the green after image in a reply post.

[Edited on 14-11-2006 by Mr. Wizard]

h0lx - 13-11-2006 at 05:30

I tested the first scraping of turnings by sprinkling some KNO3 and sulfur on top. was ignited with a piece of a blackmatch which was from a bad batch. it emerged into a large bright ball of crackles, which made me see a large green area infront of my eyes for an hour. Going to try other combinations too today. KMnO4 should be furiously violent and dangerous, but that's what small amounts and thick leather gloves were invented for;)

quicksilver - 13-11-2006 at 07:31

what size are the turnings? Ca is very unique stuff. Are you planning on using an oxidizer? By working with a "gentler" oxidizer 1st and moving forward you may find something interesting. If a reducing agent (S) produced the above illustrated result; think what an oxidizer would do! I have a wee little voice telling me that this a resipe for a serious conflagation (but it could be fun). :P:o:P:o If I were to try it I would think of some method to stay far away (at least a couple of meters) from it even in a sub-gram level. I know that I am preaching to the choir on that score; the reason I ask what size the turnings are is that if they can be made small enough, you would have more alternatives as to usage. HOWEVER if they are reduced in size the sensitivity would increase enormously. The Ca - flash seems like an Armstrong's mixture best made with a whetting process via a clean solvant......IF the size of the Ca is small.
But in most quantities of turning there are SOME powder that is tiny...enough perhaps to sensitize a somewhat tame mix of larger turnings and reducing agent / fuel / oxidizer.

[Edited on 13-11-2006 by quicksilver]

h0lx - 13-11-2006 at 07:57

the turnings are about 2x1mm flakes, made by drilling into it with a specific type of wood drill bit with low speed. They are brittle enough to be ground in a mortar+pestle but I've yet to do that. They are stored under gasoline, because the default oil the Ca comes in is too thick to get nicely off the flakes.

Zinc - 13-11-2006 at 08:41

Yesterday me and my friend ignited a small amount of KBrO3/Al/S flash powder.
It burned slower than the KClO3/Al/S flash powder probably because it was not mixed in the right ratio.

Also I have read (I do not remember where) that a mixture of KBrO3 and S ignites itself after a few hours. Is that true?

Jdurg - 13-11-2006 at 09:45

Be very careful with your Ca turnings stored in gasoline. If any water gets in there, you will have a massive fire on your hands. Gasoline and its vapors very easily ignite, and if a fire breaks out the presence of the calcium turnings in the gasoline will make using water a very big 'NO-NO'. :D
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