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[*] posted on 18-4-2011 at 12:57


Quote: Originally posted by quicksilver  
Blasty:
I accidentally lost your comment it responding to it: apologies. But it DOES explain the Cab-o-sil issue indeed. You were right on track (IMO). Yes. anti-caking agents really DO have a positive affect. As do the use use of "spread" size spectrum ingredients. Whenever exampling a deglagration of DDT element, especially in a mechanical composition, you will see this agenda often raise it's head.

Cab-O-Sil has always worked for me, and when it worked it worked
well. I would posit three reasons —

It it v/ very hard and not compressible thus creating interstitial
space through which the flame can propagate.

Its specific heat is high enough that it helps transfer heat through

the comp.

I have found that when it is added in small %'s if the case is
tapped on a hard surface ... 5-10% more comp can be loaded
into the case.

These from the late Dr. Shimizu's Fireworks From A Physical
Standpoint, a translation from the German by Alex Schuman
of Feverwerk von physikalischem Standpunkt aus (1976).
Published in four parts by Pyrotechnica Publications, 1981.

With a little simple math you can calculate the IS of spheres. To
find it in layered spheres ... a bunch of ball bearing or some such
and a graduated cylinder would enable on to derive a formula to
calculate it for different size spheres. For the truly driven it can be
approximated by mercury porosimetry.

NB - Dr, Shimizu's comment about large particle black powder
burning faster ... only works in open systems... thus cannon use
large particle BP, rifles/pistols faster burning small particle BP.




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[*] posted on 20-4-2011 at 07:22


Good point; also an excellent example.

Particulate hardness properties are a valuable topic in themselves. Mg is decidedly harder that Al (thus the flaking in Al, granularity in Mg). The Cab-O-Sil hardness and size property is a valuable addition to a great many materials.
Flash has still some "undiscovered country" in it's make-up and utility. When efforts were made to maintain the shift of commercial Flash to the standard 70/30 there were those who continued to use a temperature lowering agent(s) such as sulfur (or a sulfide) in the hopes that increased flame sensitivity would provide a faster combustion spread. It was thought that this faster combustion aided simple report utility in sound-oriented pyrotechnics.
It would seem that Konski (sp?) may have blurred the concept by his discussions of the use if Ti (& some other additions) and their [lack of] effect on sound volume. (See presentations of flash power sound levels; PGI Series '96) It would seem that Shimizu may have been correct in his assertions that compositions w/ a third temp-oriented component were louder.


RIP: Takeo Shimizu 1912-2011 Died in February of this year at the age of 98. Began work in pyrotechnics in 1951 until his death by natural causes. Was said to have spoken more than half a dozen languages & continued with Koa Fireworks / Japan until his passing.




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[*] posted on 20-4-2011 at 09:30


Quote: Originally posted by quicksilver  
It would seem that Shimizu may have been correct in his assertions that compositions w/ a third temp-oriented component were louder.

RIP: Takeo Shimizu 1912-2011 Died in February of this year at the age of 98. Began work in pyrotechnics in 1951 until his death by natural causes. Was said to have spoken more than half a dozen languages & continued with Koa Fireworks / Japan until his passing.

Yes. Dr. Shimiz's Thunder #3 gets my vote.

Also - never underestimate the advantages that can be had
by good containment ... well not that good — think
fireworks not infernal devices.

Heavy walled - parallel wound tubes work wonders for output.

Flash compositions of some types will cause explosions in the
lightest of containers even sometimes in just a few turns of paper
but it also happens that these compositions are extremely brisant
and sensitive. Horrifying mixtures of potassium chlorate, pyro
aluminium, sulphur and barium nitrate have been employed and
should be avoided at all costs. Mixtures of the perchlorate, sulphur
and bright aluminium are safer and appear to be used extensively
in the U.S.A. and Japan, but even these would be considered
dangerous by many of us in Europe. In fact the more common
European technique is to use a strong paper tube with a
composition consisting simply of potassium perchlorate and dark
pyro aluminium.


Ronald Lancaster Fireworks: Principles and Practice


In memoriam Dr. Takeo Shimizu

When beggars die there are no comets seen;
The heavens themselves blaze forth the death of princes.

Calpurnia

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[*] posted on 20-4-2011 at 16:30


Quote: Originally posted by The WiZard is In  
Also - never underestimate the advantages that can be had
by good containment ... well not that good — think
fireworks not infernal devices.

Heavy walled - parallel wound tubes work wonders for output.

Flash compositions of some types will cause explosions in the
lightest of containers even sometimes in just a few turns of paper
but it also happens that these compositions are extremely brisant
and sensitive. Horrifying mixtures of potassium chlorate, pyro
aluminium, sulphur and barium nitrate have been employed and
should be avoided at all costs. Mixtures of the perchlorate, sulphur
and bright aluminium are safer and appear to be used extensively
in the U.S.A. and Japan, but even these would be considered
dangerous by many of us in Europe. In fact the more common
European technique is to use a strong paper tube with a
composition consisting simply of potassium perchlorate and dark
pyro aluminium.


Ronald Lancaster Fireworks: Principles and Practice


Indeed, I can attest to this. The perchlorate flash powders even work well with Kraft paper home-made tubes, while the nitrate and sulfate flash powders not so much. But if you strongly enclose these non-perchlorate mixtures in those professional pyro tubes they deliver a great report.
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[*] posted on 22-4-2011 at 21:54


There was some experimentation going on with the sulfate based powders several years ago by a few people I am acquainted with. The production of several pounds of flash for large bottom shots and canister shells makes some people uneasy understandably. I believe they had the best luck with larger salutes using an initiating charge of a more typical flash powder, such as 70/30. As has been found, they never had great luck with smaller salutes. I don't recall if they ever tried something intermediate in size, say 1" ID x 2.5" long as would typically be used as salute inserts in some shells.
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[*] posted on 23-4-2011 at 14:30


Quote: Originally posted by Mumbles  
There was some experimentation going on with the sulfate based powders several years ago by a few people I am acquainted with. The production of several pounds of flash for large bottom shots and canister shells makes some people uneasy understandably. I believe they had the best luck with larger salutes using an initiating charge of a more typical flash powder, such as 70/30. As has been found, they never had great luck with smaller salutes. I don't recall if they ever tried something intermediate in size, say 1" ID x 2.5" long as would typically be used as salute inserts in some shells.


Barium sulfate flash powder (6 barium sulfate, 3 very fine atomized aluminum, 1 sulfur + a bit of black powder to help ignition) in 1 gram charges inside strongly sealed pyro tubes (1/4" ID x 2-1/2" long.) The report is very loud.

[Edited on 23-4-2011 by Blasty]
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[*] posted on 23-4-2011 at 17:32


How fine is fine? Less than 5 micron?

I could definitely see sulfur making a difference. I don't think they were using any axillary fuels.

[Edited on 4-24-2011 by Mumbles]
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[*] posted on 23-4-2011 at 20:53


I put a test batch together tonight, and the mix was made with German dark flake 5micron Aluminium and B-sulfate ..

The result was a very bright green-white slow burning mix (Slower than B.P.), nothing I'd associate to flash's energetic burn .. I'd have to say that copper oxide flash/thermite is by far much more energetic.

**Is this normal , or is something off here?

I have in past made the B-sulfate flash with out the sulfur , and it failed to burn energetic......maybe the ratios where off (like 1 to1), I dont remember, but it just smoldered and left behind a solid ball of molten Aluminium. The sulfur really helps lower the temp of the ignition.

Neat stuff though ....

[Edited on 24-4-2011 by pjig]
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[*] posted on 23-4-2011 at 22:23


Ok after satisfying a second idea...., I used a piece of quick match to ignite the B-sulfate flash ,and what a difference !!!! It reacted like flash and went with a thump.... I now realize another fellow claimed this in a earlier post.He stated that the mix needs a boost to get to the needed temps for it to react like a flash mix.

I'd post a short vid. but it is in 3g format and my software is old and refuses to let me get it converted to windows media format.
Next time Ill use my dig cam ... w:)
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[*] posted on 23-4-2011 at 22:25


Quote: Originally posted by pjig  
I put a test batch together tonight, and the mix was made with German dark flake 5micron Aluminium and B-sulfate ..

The result was a very bright green-white slow burning mix (Slower than B.P.), nothing I'd associate to flash's energetic burn .. I'd have to say that copper oxide flash/thermite is by far much more energetic.

**Is this normal , or is something off here?

I have in past made the B-sulfate flash with out the sulfur , and it failed to burn energetic......maybe the ratios where off (like 1 to1), I dont remember, but it just smoldered and left behind a solid ball of molten Aluminium. The sulfur really helps lower the temp of the ignition.

Neat stuff though ....


Never tried it without the sulfur. With it it works very well, though, except that it still is a bit difficult to ignite.

[Edited on 24-4-2011 by Blasty]
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[*] posted on 23-4-2011 at 22:34


Quote: Originally posted by Mumbles  
How fine is fine? Less than 5 micron?

I could definitely see sulfur making a difference. I don't think they were using any axillary fuels.

[Edited on 4-24-2011 by Mumbles]


I use 3000 mesh atomized aluminum powder. This one:

http://www.alphachemicals.com/aluminum_powder

Works very well with other oxidizers too. Seems more insensitive at first than dark pyro aluminum (which makes it safer to handle and mix, IMHO), but once it gets ignited it reacts very fast due to the very small particle size.
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[*] posted on 24-4-2011 at 15:36


Quote: Originally posted by Mumbles  
There was some experimentation going on with the sulfate based powders several years ago by a few people I am acquainted with. The production of several pounds of flash for large bottom shots and canister shells makes some people uneasy understandably. I believe they had the best luck with larger salutes using an initiating charge of a more typical flash powder, such as 70/30. As has been found, they never had great luck with smaller salutes. I don't recall if they ever tried something intermediate in size, say 1" ID x 2.5" long as would typically be used as salute inserts in some shells.

Some years back in an attempt to make a fountain I put
a 'hole bunch of K perchlorate and fitter (really large
flake) aluminium in a 3" of so cardboard tube from the supermarket
that still had 3" of that thin plastic wrap they use on meat trays
&c., wrapped around it. Indestructible sez I. Put couple of ounces
on 2FA in as lift .... Back off .... Watch this .... a tremendous
KABOOM you could feel in your gut with a flash so bright that had
the Space Shuttle been overhead they would have seen it. La
cardboard tube? Nowhere to be found.

This in an open ended tube. Never underestimate the pyrotechnic
advantage of a good kick in the ass.
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[*] posted on 24-4-2011 at 16:49


Unfortunately some folks think "containment" means a total encasement of an energetic material; such is not the reality. Even slower deflagrants
(nitrate based & similar) can occasionally pop with an open end.


Very few rocket hobbyists forget their first CATO.

[Edited on 25-4-2011 by quicksilver]




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[*] posted on 24-4-2011 at 22:54


Quote: Originally posted by quicksilver  
Unfortunately some folks think "containment" means a total encasement of an energetic material; such is not the reality. Even slower deflagrants
(nitrate based & similar) can occasionally pop with an open end.


Very few rocket hobbyists forget their first CATO.


I find it quite difficult to make sulfate/nitrate flash powders and black powder "pop" unless strongly confined. They tend to just blow the lids/plugs of the container if they are not strongly fixed in place, instead of bursting the container to pieces. An excellent way to assure that the plugs are not going to be blown off is to drill 4 opposing holes close to the ends of the pyro tubes and inject the hot glue through them. This produces a very strong plug. Even 1 gram of black powder can be made to deliver a respectable bang this way.

Flash powders containing perchlorate do not need the same degree of containment. A simple hot glue plug will do.
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[*] posted on 25-4-2011 at 06:12


Mechanical mixtures often depend on the consistency of their physical intimacy (closeness of particulate to one another) for their effectiveness. That's why commercial BP is always so much more effective than most home made types.....The end user just doesn't have the facilities to get the particles in such proximity as a plant-level mixing.
If a VERY fine particulate is made from the base oxidizer (perchorate, etc) and an equally fine level of fuel / reducing agent is mixed to a high level of intimacy, the flash will have little trouble making a report from a simple folded piece of paper. The simple "triangle design" fold is often an ample test to determine this & that flash powder will self contain at 50 grams (below a 2 oz level).
There was a safety concept of placing the composition into the container one item at a time and then providing a method of shaking or vibrating to mix when contained to avoid handling the composition, prior. This never worked as well unfortunately even in plant operations with quality design.


Microscopic measurement of perchlorate particulate reduced in size through the use of a "coffee grinder" was found to be very close to single micron size (2-9 um) via empirical observation (slide measurement utility).

[Edited on 25-4-2011 by quicksilver]




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[*] posted on 25-4-2011 at 09:53


Quote: Originally posted by quicksilver  
Mechanical mixtures often depend on the consistency of their physical intimacy (closeness of particulate to one another) for their effectiveness. That's why commercial BP is always so much more effective than most home made types.....The end user just doesn't have the facilities to get the particles in such proximity as a plant-level mixing.
If a VERY fine particulate is made from the base oxidizer (perchorate, etc) and an equally fine level of fuel / reducing agent is mixed to a high level of intimacy, the flash will have little trouble making a report from a simple folded piece of paper. The simple "triangle design" fold is often an ample test to determine this & that flash powder will self contain at 50 grams (below a 2 oz level).
There was a safety concept of placing the composition into the container one item at a time and then providing a method of shaking or vibrating to mix when contained to avoid handling the composition, prior. This never worked as well unfortunately even in plant operations with quality design.


Microscopic measurement of perchlorate particulate reduced in size through the use of a "coffee grinder" was found to be very close to single micron size (2-9 um) via empirical observation (slide measurement utility).


The black powder I make (using air float charcoal, and ball-milling for 24 hours) is about as well mixed as I think it will ever get. After granulating, it burns in a quick flash with a loud "whoosh!". And you still need a strong plug to reliably make it burst the container to pieces, not just violently shoot the plug/lid out. Most of the time normal hot glue plugs will just be shot out. Another effective method is what I call "the medieval way" (after Marcus Graecus' description of the firecrackers of his times): make a paper tube and strongly tie the ends shut.

The nitrate and sulfate flash powders using the exact same sulfur and aluminum powder as the perchlorate ones, and mixed the same way (viz. tumbling/diapering the powders), still need stronger confinement to work in the best manner. Otherwise they will also tend to just blow out the plugs. With the perchlorate flash powders you can even just use home-made Kraft paper tubes & simple hot glue plugs and get a heck of a bang.
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[*] posted on 26-4-2011 at 07:05


You might have come as close to commercial-level as is possible without a ten-ton stone wheel or some crazy thing like that. When I make something with BP I also remind myself that generally almost half (about 46%) of the material is converted into solids in the smoke elicited from it's burning. This is often not wasted but allows the "gas" to have a degree of pressure behind it in a confined space design. However that is a very good example of when the design needs to be a full enclosure.

Explosive wave patterns and strength have been studied (L. Walt and Cooper) & if speed were dismissed, some materials explosions have very powerful "breaking fronts" in that they are able to do work that is not accomplished by many "faster-than-sound speed" blast waves can achieve. I always thought this was fascinating & I believe it was one of the reason why BP was used in blasting for centuries. Unfortunately these studies have never been preformed on per / chlorate type mechanical-compositions explosives. The strength on a small to moderate scale leads me to think that they too have a vast amount of solids in their released gas & that may be one of the reasons why they are SO powerful per unit weight.


I was trying to find a picture (now long gone) of a motor that pushed a BP rocket well beyond what I had done with a smaller (D -?) motor with ammonium perchlorate.

[Edited on 26-4-2011 by quicksilver]




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[*] posted on 26-4-2011 at 22:11


Quote:
I use 3000 mesh atomized aluminum powder. This one:

http://www.alphachemicals.com/aluminum_powder

Works very well with other oxidizers too. Seems more insensitive at first than dark pyro aluminum (which makes it safer to handle and mix, IMHO), but once it gets ignited it reacts very fast due to the very small particle size.


In a not all that scientific study done by Ken and Bonny Kosanke, they found a similar aluminum was even more powerful than the more traditional dark flakes. If one were to believe their results, it would make sense that more powerful = more sensitive. I think dark flake Al flashes are less sensitive than some lead on to be.



Quote:
Mechanical mixtures often depend on the consistency of their physical intimacy (closeness of particulate to one another) for their effectiveness. That's why commercial BP is always so much more effective than most home made types.....The end user just doesn't have the facilities to get the particles in such proximity as a plant-level mixing.


I'm going to have to disagree with this statement. Commercial powders are based on consistency, not ultimate strength. It is a fairly simple feat to make powders at home that easily outpreform commercial BP. I suppose it depends what you mean by "effective", but in a scenario such as lifting or breaking shells it's quite an easy feat.

Related to this, in another post, the large wheel mills do no actual grinding of particles. Everything is pre-milled in large ball mills. The wheel mills kneed the dampened powder together. Achieving a similar level of particle size of individual chemical in a homemade ball mill is probably very approachable, though likely not as quickly as one could do so with a 10ft diameter mill.


Quote:
The nitrate and sulfate flash powders using the exact same sulfur and aluminum powder as the perchlorate ones, and mixed the same way (viz. tumbling/diapering the powders), still need stronger confinement to work in the best manner. Otherwise they will also tend to just blow out the plugs. With the perchlorate flash powders you can even just use home-made Kraft paper tubes & simple hot glue plugs and get a heck of a bang.


Do you not feel comfortable screening said mixtures for some reason? Commercially when making flash, as well as all prominent shell builders, regularly screen all of their flash. It is typically of a KClO4/Al, or KClO4/Al/S mix. There is no other way to safely make large batches, nor get the mixture as intimately mixed. There is a noticable difference between something screened vs. just diapered. As a very well regarded pyro, Mike Swisher, once so elequently put it; Diapering is for babies.

Adding the individual chems to a casing and relying on handling the device during spiking, pasting, finishing, etc is generally regarded as the binary method. It's really only acceptable for ground salutes or rockets. Neither are things I have much interest in (each for different reasons). Doing something like that for shell inserts or bottom shots is actually quite dangerous. It makes shells much more likely to flower pot. In the days of handfiring, this is about as devastating as it could get.


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[*] posted on 26-4-2011 at 23:58


Quote: Originally posted by Mumbles  

In a not all that scientific study done by Ken and Bonny Kosanke, they found a similar aluminum was even more powerful than the more traditional dark flakes. If one were to believe their results, it would make sense that more powerful = more sensitive. I think dark flake Al flashes are less sensitive than some lead on to be.


I think that even the aluminum of commercial firecrackers (which is not dark pyro) is easier to ignite than this fine atomized aluminum. Even in mixtures with perchlorate and sulfur you can still notice that it's a bit difficult to ignite. Don't get me wrong, this stuff gives a fast reaction once it ignites, but the thing is to get it ignited first. But I might double-check this by preparing a small sample of the aforementioned strontium sulfate flash powder with dark pyro aluminum (I still have a can of it somewhere around) and see if it ignites more readily than with the fine atomized aluminum (it couldn't be any harder; the sample I prepared with this atomized aluminum had to be heated with a lighter-torch until it was glowing for a while before it went off.)


Quote:
Do you not feel comfortable screening said mixtures for some reason? Commercially when making flash, as well as all prominent shell builders, regularly screen all of their flash. It is typically of a KClO4/Al, or KClO4/Al/S mix. There is no other way to safely make large batches, nor get the mixture as intimately mixed. There is a noticable difference between something screened vs. just diapered. As a very well regarded pyro, Mike Swisher, once so elequently put it; Diapering is for babies.


I do not prepare large quantities of it, so I do not resort to screening. Diapering/tumbling gives good enough results in smaller batches. Large quantities of flash powder are very scary, even the safer ones, like the sulfate-based powders, would make me uneasy in large quantities.
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[*] posted on 27-4-2011 at 08:19


I tried to be pretty careful with my verbiage: "consistent" is something I would go with. But yet I believe that the level of consistency of commercial BP (IF we confine that to 75/15/10) would still have an edge on home made in more than just consistent make-up. Proper corning is something that a guy has a tuff time with making that would top commercial in a utilitarian perspective.
I'd say this; if it absolutely has to be presenting a specific burn rate, etc. Commercial has the edge. IF we are looking for a 75/15/10 that is simply faster burning than a ffff, I agree someone could do it without plant-level apparatus.

But this is all subjective anyway.

I DID see one of the best mixing utilities for flash in a long time, that someone made. They took an old electric toothbrush (battery powered) and placed a piece of plastic tubing about 12" long ( approx 1/4" ID) on the tip and it vibrated remarkably well. It also did not seem to store static energy. When the composition was placed in a contained (ceramic for lack of conductivity) the end of the tube was placed within. The vibration was so minute and fast, it mixed it with amazing rapidity (& very well) that it was completely mixed in a pretty damn safe manner.
I have experimented with diapering and never got a really good mix & settling had been a problem. This technique kept any static from building and the tube vibrated SO fast but in very tiny increments, that it did a better job than most methods.


[Edited on 27-4-2011 by quicksilver]




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[*] posted on 15-9-2011 at 13:01


Quote: Originally posted by Mumbles  


In a not all that scientific study done by Ken and Bonny Kosanke, they found a similar aluminum was even more powerful than the more traditional dark flakes. If one were to believe their results, it would make sense that more powerful = more sensitive. I think dark flake Al flashes are less sensitive than some lead on to be.



There is more to this than many know. The use of powdered Al in Mil-spec applications is not "dark pyro"
Powdered Mg, although it does not flake, is often less reactive once it gets lower (smaller) than a certain optimum size. But that's another story: the particulates often fit together like a puzzle and become more difficult to ignite when not used as an air-float but in a standing solid.

In any grouping of size in Al there is often very tiny particulate, far smaller than the average (325 mesh will often contain a substantial percentage of 2um, etc). Therefore in large military-industrial applications the idea of using "dark-pyro" is a serious waste of funds. Ekherk provides it's products for inks and goes to a great deal of trouble to make it sizing consistent. It's actual cost is very high when compared to actual industrial Al flake in bulk.

Realistically an adulteration one-to-five use of a "dark-pyro" Al in 325 bright flake is more than appropriate for pyrotechnic use. And that 6 pound end-product has often been used as the examination of many bulk sales has shown that to be a realistic ratio of single micron size within non-specialized Al powders.
Ekhert powders was originally designed for inks and finishes (due to the effort toward consistency in size) and only later in their company's history did they manufacture a "pyrotechnic oriented" product line. Please see Ekhert's web site for additional information in product line application & design.




[Edited on 15-9-2011 by quicksilver]




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[*] posted on 11-7-2013 at 22:39


Could a chlorate based petroleum exlosive be initiated with a decent flash-powder-based or ammonium perchlorate based metal composition charge utilized as a detonator?
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