Black Powder

[MrMagnum]

An employee of an explosive company told me that black powder can detonate under certain circumstances. Furthermore he told me that it would have a velocity of detonation of more than 1.000 m/s.

A few days ago I read an old German book on black powder and found the same information. The author writes that black powder can detonate, if it is very hard confined and primed by a blasting cap.

Is there anybody with any further information or experience on that?

[simply RED]

Black powder "detonates" at 1,5-2 km/s with 5% Al superfine metal powder.
Enclosed in steel pipe 5 cm diameter.

[Marvin]

Information suggests that it is less 'detonating' and more the det wave from the cap passing through the mixture, setting it off but not being amplified, cf copper oxalate in Davis. Strong confinement probably preserves the det wave better, confining it to the tube instead of allowing it to expand in 3D decreasing in intensity as area increases.

[metal dragon]

This is most probably wrong but it is something to consider. What if the KNO3 were detonating such as NH4NO3 can detonate with out any additives. Or KNO3 were somehow sensitised by the C or S again such as ANFO ?

[MrMagnum]

This is a really good idea, metal dragon. I'm thinking the same way. Perhaps it would be interesting to do some research on a mixture of KNO3 and fuel oil. Maybe it's possible to set it off with a large booster charge?!

Most people don't believe that KNO3 could be an explosive. But maybe it is an explosive which is less sensitive than AN.

[vulture]

KNO3 is not an explosive because it's decomposition reaction is highly endothermic and it produces much solid in comparison to NH4NO3.

The decomposition of NH4NO3 is much less endothermic and the entropy of the products is far greater and therefore the Gibbs energy makes the decomposition nearly spontaneous once it has started.

[MrMagnum]

Maybe it becomes a high order explosive when mixed with a fuel, i.e. fuel oil or something like that. I don't know it exactly.

[kingspaz]

MrMagnum, think before you post. what do you think chacoal and sulphur is? FUEL!

Marvin, i have to agree with you. i believe the shockwave from a very strong detonator would power the effective decomposion of the KNO3 throughout the whole charge. since fuel would be present the combustion products would provide the expansion. i think thi sort of 'combustion' would take place at the speed of the detonator shockwave propagation through the charge. the effect would not be a true HE but more of a medium between an HE and an LE.

thats what seems to make sense to me anyway.

[crackedchemist]

Well if that was the case then couldn't it be used as a booster?

[MrMagnum]

kingspaz, I know that charcoal and sulphur are fuel. You just misunderstood me. Let me explain:

When NH4NO3 is mixed with a fuel - being it sulphur, charcoal, fuel oil or anything else - it's properties as a HE are improved. The same seems to happen to KNO3, because Black Powder can get a HE (or something between LE and HE) under special circumstances. This reminds me of NH4NO3, but I don't forget that NH4NO3 is "more explosive" than KNO3. With my last post I meant only liquid fuels as they penetrate the KNO3-grains. This results in a better contact between KNO3 and fuel, possibly improving it's HE-properties compared to Black Powder as a mixture of three solid substances.

[kingspaz]

MrMagnum, if the BP is a fine powder as it should be, and it has been prepared properly, then the same effect will be achieved. recall the preparation of BP where some KNO3 is precipitated within the pores of the charcoal. sensitivity is irrelevent as the size of detonator that would be required is massive. any small differences in sensitivity between preparitory techniques and fuels would be relatively insignificant given the power of the detonator that would require. this of course relies on what marvin and myself have said and whether or not it is correct.
i do believe however that fuel oil would sensitise KNO3, but then so would many fuels...

crackedchemist, no. it wouldn't be possible to use as a booster since it can't support its own detonation.

[MrMagnum]

It would be interesting to do some testing with Black Powder. An ordinary blasting cap would not be strong enough but maybe a blasting cap and a booster charge made of Dynamite or RDX. And the Black Powder has to be confined in a strong metal tube. The most interesting would be the VoD.

[metafractal]

What is the point of this!?
In your charge, the detonation of the BP will be so pathetic compared to that of the booster that, even with a controlled experiment you will barely even be able to tell whether it detonated or not. Using a larger charge of BP is no solution. As BP either has no or practically no ability to propagate a shockwave itself, the cap actually does the detonating of the BP rather than the initiating of a BP detonation. Therefore, the cap will always need to be larger than the base charge! (In terms of power, not physical size :rolleyes: )

If what you are seeking out of this is a cheap, easy, low VoD HE, then you should try CHFO (http://www.roguesci.org/theforum/showthread.php?s=&threadid=3141).

BP is useful as an shock insensitive, flame sensitive, cheap, heaving low explosive. It has absolutely no use as a high explosive, and it's detonation is no more than a novelty.

[MrMagnum]

It's detonation is proved by Dynamite Nobel Explosives and test results I read in an old book about Black Powder from 1916. The vod of my test charge can be measured an compared to Black Powder set off under normal conditions.

[kingspaz]

metafractal, the point is that its new information being brought to the table for discussion. and discuss is what we will do.

MrMagnum, would it be possible to scan the relevent pages?

[MrMagnum]

Yes, it would be possible to scan the pages. I got a lot to do this weekend, but I will show you the page within the next days.

[gliper]

"When NH4NO3 is mixed with a fuel - being it sulphur, charcoal, fuel oil or anything else - it's properties as a HE are improved. The same seems to happen to KNO3, because Black Powder can get a HE"

No as explaned earlier KNO3 CAN NOT explode or burn on its own all it can do is separate into K2O and NO2 and take a lot of heat out of the reaction. The NO2 then oxadises the fuel. AN has both an oxadiser NO3 and a reducing agent NH4 so 2 oxagens are reduced but one remains hence you add fuel to balence the reactants to increas power.