Shock resistant "primer" comp

[Swede]

Ledgards massive book "Preparatory Manual of Black Powder and Pyrotechnics" is a fascinating collection of thousands of compositions, ranging from pyrotechnics, to tracer formulas, thermites, many others. The bulk are too dangerous, too exotic, but that still leaves hundreds of excellent comps. One of them caught my eye...

 

Shock resistant "primer" composition (produces flash and loud report upon ignition)

 

It is a mixture of 61% K-perchlorate, and 39% K-ferricyanide. The comp is prepared by saturating a water solution with the two ingredients, then forcing the bulk to precipitate by adding alcohol. The filtrate is dried, then milled. He reports the energy output as comparable to Pb styphnate.

 

I am not interested in it for anything other than perhaps a core for crackling stars, or other popping/crackling noisemaker. Perhaps the material could be doughed with nitrocellulose lacquer, or otherwise bound, to lend it some rigidity for star use. He mentions it can be pressed. The fact that it is shock-resistant is a plus.

 

The MSDS for K-ferricyanide is not alarming. Acids are forbidden, of course, but otherwise, the stuff isn't bad. Relatively cheap, too.

 

I'm interested in giving this a shot. Ledgard mills EVERYTHING in his book which I think is a bit nuts... I think I'd rather mechanically mix the wetted powders, or find some other, gentler means to test it, at least initially.

 

Has anyone tried this comp?

[50AE]

It's maybe off-topic, but a friend of mine tried

 

K4[Fe(CN)6]

S

KNO3

 

I don't know the ratios. He says it's insensitive, because he made shock and friction tests with it. Also, that it gives a bigger energy output than normal black powder.

[Mumbles]

It was insensitive because he used KNO3, and not chlorate or perchlorate as traditionally used.

 

I read through this thread on rec.pyro and it may be helpful to you. I would definately not mill it. I believe there is some information out there for using this co-precipitate as a break charge in crossettes.

 

Also, definately not shock resistant. Far from it. A similar mixture was used in guns as primers. There is a nice table in the thread from shidlovskii.

 

http://groups.google.com/group/rec.pyrotec...1430aeda1894515

[Swede]

Thanks for the resources, Mumbles.

[frogy]

I was going to say... It is definitely not, non-sensitive...

 

Here's a Youtube video of 50mg underwater

http://youtube.com/watch?v=-HFF0s4YIe8

 

I think a solution would be rather hard to make, since KClO4's solubility is only like 1.5g/100ml

 

Chlorate\Ferro\Ferric-Cyanides and Perchlorate\Ferro\Ferric-Cyanides were even abandoned by the government, due to sensitivity issues... So they're definitely not be messed with.

[Mumbles]

It is very low at room or colder temperatures. However at boiling it is quite soluble. A few hundred grams per liter I believe.

[Swede]

I tried a 5.0 gram sample. Dry mixed (rolled in a small cup until uniform) it created a powder that burned very fast, but slower than good FP. I was unable to ignite it via shock, probably because the mixture was not intimate enough. I then attemped a precipitation per the recipe, again about 5 grams. The yield was horrible, perhaps 2 grams, but worse, it was inert. The ppt did not form in the correct ratio.

 

I may try again at a later date, but I see nothing here other than a curiosity. Perhaps it is a way to make a slow FP for a small burst or aerial salute, in a pinch, if you have no flake Al.

 

Thought - if it performs like FP, it may be a cheap substitute, as K-ferricyanide is about $10/lb, probably much less in bulk. However, I would not mess with it in any significant quantity until more is known... true tests to see how it compares to FP in sensitivity, reactivity, static ignition, etc, under controlled conditions.

[frogy]

I'd like to again throw in my 2 cents... Soon I'll be up to a few dollars

 

I can guarantee you that when properly mixed, this composition is a force to be reckoned with. It is sensitive, fast, and mean.

 

$10/lb. isn't really much of an advantage over $13-$15/lb. for pyro Al at normal prices... Normally you can grab some off a buddy on Passfire for half that.

[Swede]

I'd like to again throw in my 2 cents... Soon I'll be up to a few dollars

 

I can guarantee you that when properly mixed, this composition is a force to be reckoned with. It is sensitive, fast, and mean.

 

$10/lb. isn't really much of an advantage over $13-$15/lb. for pyro Al at normal prices... Normally you can grab some off a buddy on Passfire for half that.

I'll take your word for it... there don't seem to be any properties on the surface that make it a superior composition over traditional mixtures in pyrotechnics. I wish Ledgard hadn't declared it to be "shock resistant" if in fact it is not.

 

It would have been nice to add another comp to the list of traditional bursts, if the handling was in fact safer, but if it is truly nasty, then there is no advantage.

[frogy]

I'd like to see some more research based on this composition, though if you do not already have the components, you may be throwing money into the wind.

 

I haven't made the composition myself, but from videos and other pyro's explanations off Rec.Pyro, it seems like quite a nasty composition to be putting into shells\etc.

[Swede]

Can you elaborate? What made it nasty? FP has some uses beyond salutes, and if there is a safer alternative, it would be nice, I think.

 

If it turned out to be a simple yet potent burst for small shells, or to perhaps boost larger ones, and not display the sensitivities of FP, it might be worth pursuing. It might be an alternative to whistle. Perhaps a third component might tame it a bit, such as a portion of airfloat in place of the ferricyanide, or maybe a benzoate.

 

I don't know the physics of why FP is as sensitive to static as it is, but I suspect it is the metallic content. K-ferricyanide is an organometallic, not a reactive metal powder. By itself, it displays no bad traits. Mixed, it's a fuel/oxidizer, probably like KP except with a bit more punch.

 

There's simply not too much known about it. Web references are scant, and it seems word of mouth or rumour is all we have. I wish I had a real lab setup, with instrumentation to properly test comps for physical characteristics.

[Mumbles]

I'd go with a carbonate such as calcium or barium carbonate if you were going to try to cool it. My computer is running like a piece of shit, and it would take forever to get at my references for this. There are probably several patents on mixtures like this. It was used in gun primers briefly IIRC.

 

If I had any ferricyanide around I would prepare concentrated solutions of both and mix them in the right proportions. From there they could be crash cooled, or precipitated out with the addition of alcohol most likely. You could also calculate how much of each you'd need to get the right proportions to precipitate out. The solubilities at 100 and 0C are given below in g/100mL water. Seems I was mistaken about the solubility of perchlorate, or my calculations are off.

 

Swede, if you'd like, I could see about getting some of the information from Principles of Pyrotechnics by A.A. Shidlovskii. He has some stuff in there that would be right up your alley. There are some diagrams of friction and impact testing devices that look pretty easy to recreate at home. Well the impact one is really easy. It consists of 2 steel rods and a guide with measurements on it. Sample goes in between, the top rod is dropped, and away we go. It might even be worth a purchase if you were so inclined. I seem to remember you saying you started your career as a chemist, so most of it should be understandable.

 

Chemical Temperature Solubility (g/100mL)

 

perc 0 0.704934542

Perc 100 22.95585885

K3Fe(CN)6 0 31.40604468

K3Fe(CN)6 100 88.67924528

K4Fe(CN)6 0 14.28571429

K4Fe(CN)6 100 75.74692443

[Swede]

Mumbles, I did get a BS in Chemistry, but that was 24 years ago. I spent a very short time in an Air Force lab, then went into aviation, and never put my degree to much use. I still have many of my reference books, including the CRC Handbook of Chemistry and Physics. One of the things which originally brought me here is my continued interest (and beginning research) into alternate propellants; BP replacements, and such. Cool fireworks is a bonus!

 

I am making a special test rig, which consists of a .50 cal smoothbore tube, and a breech assembly equipped with a piezo pressure/strain gauge, as well as a "CUP" style of copper crusher, except I am going to use lead wire as the deformation medium.

 

I can see that friction and impact testing devices will be necessary, as any marketable propellant that is more sensitive than BP is automatically rejected as unsuitable. BP replacements are considered "smokeless powder" by the BATFE, and that gives them huge shipping and storage advantages. So yes, any references or links you can point me to would be greatly appreciated. I need to be methodical with this, and that requires more than "It ignites with a hammer blow"!

 

While a straight perchlorate-ferricyanide mix would be far too potent as a firearm or rocket propellant, if tameable it could perhaps find a role in pyrotechnics.

 

Thank you for the references, as well.

[azure]

I've been experimenting a bit with KFeCN6 and have 2 videos that might be worth watching if you're interested in this compound.

 

 

[Mumbles]

Do you really think it's a good idea to be testing quite sensitive stuff on glass petri dishes? It's going to self confine some day (if you make it right), and you'll not be happy then.

 

How exactly do you expect two fuels, sodium benzoate and potassium ferricyanide, to burn in a rocket? I think you're just seeing the whistle mix and other comps in that rocket actually providing thrust.

 

Thirdly, this mix is best prepared by co-precipitation, not just mixing the two. You'll never get it as intimate.

[azure]

Do you really think it's a good idea to be testing quite sensitive stuff on glass petri dishes? It's going to self confine some day (if you make it right), and you'll not be happy then.

 

How exactly do you expect two fuels, sodium benzoate and potassium ferricyanide, to burn in a rocket? I think you're just seeing the whistle mix and other comps in that rocket actually providing thrust.

 

Thirdly, this mix is best prepared by co-precipitation, not just mixing the two. You'll never get it as intimate.

 

I apreciate your concern but i have never had any problems testing small amounts of composition on a petri dish except the glass cracking because of the heat of for example strobe composition.

This particulair mix does not self confine either , it just burns exceptionally fast and yes i made it by co-precipitating the ferricyanide with the perchlorate from boiling water using a magnetic stirrer on high speed and subsequently vacuum filtration of the precipitate. You would not get this kind of burning rate by simply screening the two together.

 

How it works out for a rocket fuel we'll see. From what i've seen during my tests so far, i do think the nitrogen of the ferricyanide helps to increase the rocket thrust and definitely makes the composition more brisant in general.

In the particulair rocket from the video there was a substantial amount of potassium ferricyanide used in the composition and i doubt that the thrust just came from the NaBenz part.

Apart fron Sodium benz i have also tried to combine it with Potassium salicylate but i'll need to use a binder because of the more brittle nature of Potassium Salicylate.

 

I'll have to find a remote enough location to do some thrust measuring of different whistle- and related compositions to say anything more about it really.

Edited August 25, 2010 by azure

[Mumbles]

What I meant is that it appears that you have two fuels mixed together. There is clearly no oxygen being given off. Something has to be oxidized, and something has to be reduced for it to combust. I see nothing that would do this. The energy to break the carbon nitrogen bond is huge even with the thermodynamic sink of producing N2. You can't just split off the nitrogen and leave the carbon and potassium hanging around.

[azure]

In this case KClO4 was used as the oxidiser.

Do you really think i would be able to build and launch whistle-,strobe- and expirimental rockets if i didn't know about basic redox reactions ?

 

Ah well back to the batcave..

Edited August 26, 2010 by azure

[Mumbles]

OOOOOOOOOOOOOOOOOOOOOOOOOO, I got it. The way you had it written, it gave me the impression that you were using solely sodium benzoate and potassium ferrocyanide as a propellant. In reality, you're using them as a mixture of fuels in a standard whistle mix formulation. Sorry for the misunderstanding.

 

Do you really think i would be able to build and launch whistle-,strobe- and expirimental rockets if i didn't know basic redox reactions ?

 

You might be surprised how little chemistry some of the best rocketeers in the world know.

[pirotek]

вот есть мои ракеты на смеси Potassium ферроцианид с нитратом калия

кровяная соль сокристаллизована с нитратом калия упариванием

ракеты есть без сопла

http://www.youtube.com/playlist?list=PL2E4Qb6FEbZPd1IbCHKyAW5rIXlemqxTt

[MrB]

You might be surprised how little chemistry some of the best rocketeers in the world know.

I'm not one of those guys, but i'll tell you guys... Mumbles is spot on, chemistry ain't my thing. But i'm still painting.

B!