Looking for honest feedback in regards to magnalium flash

[pyroviper]

Last year I decided to purchase a star kit. Needless to say I am not going to delve into the specifics. After making more colored stars than I have ever made in a single sitting, I realized I had some left over chemicals and metals. I believe everyone has had the moment where the voice of reason is drowned out by sheer curiousity. After some research I found a recurring formula of 50/50 Pottassium Perchlorate and Magnalium. Now the mesh I had was not within the range recommended for flash grade comps. Now lets take this a littlle deeper. I believe I read somewhere that german black aluminium is created by layering aluminium with a fine layer of carbon and then another layer of aluminium. Then it's milled into powder. This gave an idea.

I coated the magnalium with a pinch of airfloat charcoal and mixed it until it resembled the color of the dark aluminium. Weighing out this mix with an equal amount of oxidiser I used the diaper method to mix it. Finally I did an unconfined test with a .5g pile. This resulted in the bright white flash and bassy thump.

Looking back I am left some questions. What did the charcoal do to allow this mix to flash. Besides the common cons of flash powders in general does anyone see any other cons to this approach.

Some final notes: The mesh of the magnalium was 125-200. Without the charcoal the performance was nowhere near the quality as the charcoal coating.Having no data on sensitivity etc the little voice of reason overpowered me at this point and I decided to not jeapordize life and limb and attempt to confine this mix until I had some outside feedback.

Besides some vague statements of magnalium flash being very powerful there is very littlle info on its sensitivity to friction and other impact.

Usability for me would be in aerial shells so impact and friction are my main concerns.

[Potassiumchlorate]

The charcoal did what it often does in star compositions: it helped in ignition.

 

I have weird feelings about magnalium flash too, because I know that potassium perchlorate/aluminium flash is less sensitive than potassium perchlorate/magnesium flash, but I don't know exactly how much. Is magnalium more like magnesium in this respect or is it somehow (for example due to the irregularity of the magnalium particles) even more sensitive? I don't know. So I use aluminium flash for reports and magnesium flash for light output. I avoid magnalium flash.

 

The more experienced might have another opinion, though.

[pyroviper]

From what I have magnalium is suppose to cut down on the cons from using pure aluminum or magesium. Specifically reactivity. However I have found very little info on the subject. I am guessing theres a reason behind this, and judging by the low quantity needed for it to report I can understand why. Unconfined this mix reported quite well, and the flash was blinding. If you have ever welded and arc'd it before dropping your helmet this is what I would compare the light emission to. I spent quite a bit on my mortars so the last thing I wanted to do was make a shell with this stuff and have it go off in the tube. They are HDPE, so there was no scare of shrapnel however I am quite fond of them lol. Hopefully some of the experienced techs can chime in on their opinions of the composition. Thanks for your feedback though, it is appreciated.

[dagabu]

I am not sure why you would even want to use MgAl in flash. In order to get it to POP, you need to grind it to a fine powder therefore making the Mg more reactive (amount of available surface) taking away any safety you though you had in using MgAl in the first place.

 

-dag

[pyroviper]

After looking thru my chemicals the magnalium came as 325mesh. I didnt grind this down. This is what i used.

[Potassiumchlorate]

325 mesh is very good. That should do for most purposes.

[mrprivate415]

ive always wondered this too

[pyroviper]

Went thru my supplies this weekend and realized I had plenty from last year left over so I decided to give this project another go. Was going to record the results but forgot to hit the record button on the camera,

 

 

The first batch was as followed:

 

---------------------

.25g MgAl (w/ light dusting of Air Float CC)

.25g KClO₄

 

Result Unconfined: Provided a low thump and bright white flash. The heavy kraft paper that it was placed on was instantly turned to white ash.

 

 

Result Lightly Confined: Provided a deep report, bright white flash and a very small shock wave that could be felt roughly 100ft away.

Damage to the wrapping was slighlty mangled, from observation this would be enough to cause serious burns to the skin

and possible damage/loss of digits. Lightly confined to me is placing the mix on a piece of kraft paper, placing a nichrome

igniter into the center and folding the paper gently around it. Then lightly wrapping some masking tape around it. Using the

squib wire in a vice to hold the device still to minimize hand contact with the device. Report was amplified with a third test

by spiking the device with some cotton string, as you would spike a shell. However spiking allowed for your hands to be in

longer contact with the device increasing chances of injury in the case of accidental ignition.

--------------------

.25g MgAl (w/ light dusting of Air Float CC)

.25g KClO₄

.15g Strontium Carbonate

 

Result Unconfined: Provided low thump and bright Orange/Yellow Flash. The heavy kraft paper that is was placed on was charred in a circular area where the flash was placed.

 

 

Result Lightly Confined: Provided a deep report, bright Orange/Yellow flash. Shock wave was not as evident as before at 100ft distance.

Damage to the device was not as severe as 50/50 comp, and seemed to follow the weekest area on the device.

Considering the path of the heat and gasses were more focused in this manner I would have to guess that this

would be more likely to remove a digit from the hand in the case of accidental ignition.

 

Other notes: Though this comp didnt have as much heat as the first nor the power, it still had a very nice report to it confined. If I also remember correctly the strontium carbonate

has the effect of de-sensitizing the composition and has the ability of neutralising acids which can cause spontaneous ignition. I am wondering if the addition of Parlon

would allow for the red to be more evident without slowing the reaction down and negating the flash effect.

---------------------

[xBangergoosEx]

Personally i stay away from it. Dark Aluminum has always worked great for flash and i dont have a need for any other types of metals. I hear too many stories of magnalium being overly sensitive to convince me to use it.

[Zingy]

I believe the term referred elsewhere in this form as "retina burning", would be the best way to describe magnalium flash. I see it being used more often in cheaper imported salute shells, especially the spherical salute shells. Most people refer to them as finale fillers, when the show sponsor, is more interested in quantity than quality.. You certainly would not want to use it in a flash bag to break star shells , crossette comets, a lampare shell, or a titanium salute shell, as the "retina burning" effect overwhelms everything the shell, or comet has visually to offer.

 

If you are only interested in noise and have no or little concern about the "retina burning" effect, it would work great. I have seen magnalium offered as fine as 3 micron, looked like H-Super Aluminum, but of lighter density. You really do not need that energetic of a flash, or incur the extra cost, in larger shells or bottom shots..

 

Pyro Viper, your 50/50 mix is really oxygen deficient. You need to atlest double the KCLO4.

[pyroviper]

Please don take this the wrong way, but I have done extensive searches on magnalium flash and have turned up very little as far as cons of its use in flash. Im not doubting what you have heard , I just haven't heard these stories nor found anything other than statements that it is powerful.

 

Come to think of it I havent been able to find much more than a couple of videos of a few dumb kids using it stupidly. As far as its sensitivity to shock, heat, friction, and conductivity there is a complete void of data available. I don't even recall any stories being mentioned.

 

Would you mind guiding me to where you have found these stories?

 

What I can offer from my limited test batches is what I have supplied so far, but this is factual data that I have recorded and documented. For example the addition of Strontium Carbonate does appear to decrease sensitivity, alters the temperature of the burn rate, and increases the ignition temp requirement.

[pyroviper]

Zingy thanks for the post. Are you saying the 50/50 mix is deficent or 50/50 + strontium carbonate is deficent.. Or both? The 50/50 comp has been the only one I have found.

 

I see your point as far as retina burning goes. However I wonder if this is as bad once it is higher up, and further away from the viewers.

 

As far as effect I am looking more for the low bassy thump report. To me aluminum gives more of a mid tone crack.

[Mumbles]

They are both going to be extremely oxygen deficient. A quick back of the envelope calculation gives a rough ratio of 77:23 Potassium Perchlorate:MgAl. It's not precise, but it should be in the ball park of the stoichiometric ratio. Acid really isn't a huge factor with regard to perchlorate based flash powders like it is with chlorates. The addition of a carbonate might actually make the mixture closer to stoichiometric. Magnesium specifically can tear the oxygen atoms away from carbonate and other metal oxides. This reaction really takes some effort to get it going. It wouldn't be entirely surprised if you found that the addition of carbonates enhances power when in sufficiently large amounts or well confined. In very small amounts it probably wont be able to get going enough, and is just acting as a dilutant. In larger amounts though, the sensitivity could increase.

 

If you want a bassy thump of a report, try black powder or a coarser less reactive aluminum grade like bright flake. The lower the pitch, the slower burning the composition.

 

For what it's worth, adding carbon is probably just making the mixture more sensitive. While flash powders often do release a lot of energy, they can have a rather high activation energy. Charcoal would lower this energy. The process for making blackhead metals is quite a bit more complicated than simply mixing charcoal in with the fine metal.

 

I'm looking for the source, but I've generally been under the impression that MgAl flash mixtures were more akin to magnesium flash powders than Aluminum in terms of sensitivities.

[Potassiumchlorate]

I'm looking for the source, but I've generally been under the impression that MgAl flash mixtures were more akin to magnesium flash powders than Aluminum in terms of sensitivities.

 

That's my feeling too.

 

If one wants a very bright flash 50:50 is very good. 77% KClO₄ seems to be very much, though. The stochiometric ratios for KClO₄/Al and KClO₄/Mg respectively are 66:34 and 59:41.

 

With aluminium I prefer Dr. Shimizu's composition with sulfur:

 

Potassium perchlorate 64

German Black 23

Sulfur 13

 

Potassium perchlorate is expensive, German Black is even more expensive. Sulfur is cheap. On top of that the report is louder.

Edited May 22, 2012 by Potassiumchlorate

[pyroviper]

Mumbles and PotassiumPerchlorate I see both of your points and appreciate the information. I definetly understand what you are saying about the cc. I believe the process of making dark aluminum involves pressing a layer of carbon in between two layers of aluminum. Then it is milled into powder.

 

Simply adding it to the powders is nowhere near the same principle.

 

It's kinda like make BP. If you don't mill it, or compress it into a puck it just doesn't have the power you would expect.

[Potassiumchlorate]

I have heard that German Black is made like this: a thin layer of paper is pressed together with a thin layer of aluminium. The paper is then charred to charcoal. Then the whole thing is milled. As the name suggests, this method was invented in Germany, more precisely around 1950. Edited May 22, 2012 by Potassiumchlorate

[Mumbles]

I've always heard they mill it with the paper still on, then char it off, but yes that is the general principle. The paper may keep it from fusing back together as it is being stamp milled. It may also make it thicker so that the milling action has more effect. With how fine the material comes out, it'd be hard to imagine that the machines used really have precise clearances of only a few microns. There is also discussion of the charring process forming some amount of aluminum carbide species, which enhance reactivity, besides just protecting the surface in addition to stearin.

 

You're right, I screwed up a little bit in my calculation. I forgot to take into account both halves of MgAl. It looks like it should be 63:37 Perchlorate:MgAl. It makes sense it falls right in between the two stoichiometric ratios you posted above, as that is essentially what I ended up approximately calculating.

[psyco_1322]

The common "good" ratio for magnalium flash is 60:40, KClO4:MgAl. I've burnt a lot of this. Most decent magnalium that is at least 200mesh works fine, 325 is even nicer and if you can get super fine stuff like 600 mesh, its insane. I don't believe it's really the magnalium that's the sensitive issue you hear about, it's usually the oxidizer, like ammonium perchlorate that makes things sensitive when mixed with magnlaium. I look at it as being safer (not really sure if it is) since the metal particles are larger. I do like the deeper thump developed from the slower pressure wave that's it creates. I use Al for flash almost all the time, it's way cheaper and I use my magnalium for more pretty stuffs.

[Potassiumchlorate]

Maybe one should test some magnalium flash after all. I rarely use magnalium in my stars, since I find magnesium to give a much brighter flame.

[pyrojig]

Maybe one should test some magnalium flash after all. I rarely use magnalium in my stars, since I find magnesium to give a much brighter flame.

 

What are you coating your mag with , K-dichromate or linseed oil? Or, are you coating it for the comps your using .

[helix]

Lancaster covers the sensitivity of flash powders in his book, it relates to sensitivity to impact and also the advantage of adding graphite to reduce sensitivity.

 

The tests were carried out using the Rotter impact test, which uses the following scale:

 

0-30 Very sensitive

30-90 Sensitive

90+ Insensitive

 

from tests carried out the following results were obtained:

 

KCLO4 37% / Mg (fine) 57% / graphite 6% - sensitivity of 70

 

KCLO4 66% / Al (pyro grade) 34% - sensitivity of 58

 

KCLO4 60% / Al (pyro grade) 38% / graphite 2% - sensitivity of 78

 

BaNO3 68% / Al (pyro grade) 23% / sulfur 9% - sensitivity of 66

 

 

Lancaster then states that "devastatingly the Chinese mixture of potassium perchlorate 45%, sulfur 15% and magnalium 40% could be as low as 20 as a result of the hardness of the magnalium particles. It may well be that the presence of sulfur sensitises the mixture"

Lancaster does not include any data on 60/40 KCLO4 / mgAl flash however.

 

 

[Potassiumchlorate]

What are you coating your mag with , K-dichromate or linseed oil? Or, are you coating it for the comps your using .

 

I use parlon as the binder, so I don't coat it at all.

[pyroviper]

Wow I must admit, I have received alot of good information from you all. It's is much appreciated, thank you.

 

 

Well this last weekend I decided to test the usability of the flash comp pure 50/50 KCLO4 and MgAl(325mesh) for breaking small shells (and igniting stars).

I mixed 5g of the Flash comp, and made up a few batches of red/blue/white stars from the skylighter star kit I purchased last year.

The shells were from a 1.75" kraft paper shell kit I purchased last year as well.

 

I used the Hot-Prime comp that came with the star kit and the BP Prime Comp kit to prime the stars.

 

I measured 2.5g of flash (which was probably light in terms of recommended burst charge, and layered the shell with stars - flash comp - stars until both hemi's were

filled. Then combined them and assembled with a couple of layers of kraft tape. Later that night I tested the shells and interesting enough they burst quite considerable

to commercial grade shells. It seemed every star was lit nicely, and spred out in a nice even chrys pattern. The flash was not overpowering, and the retina burn was non existent.

However the report sounded quite muffled, and left alot to be desired.

 

I believe this was a combination of not enough oxidizer in the flash comp (60/40 seeming to be more viable by the more experienced here), and amount of flash comp used.

Another thing I have been noticing is that this flash comp seems to have a slight delay before it actually reacts and ignites. I'm thinking this is also because of the improper o/f ratio.

 

I think I will run a few more tests this weekend, and then move onto more artistic things like improving on the MgAl fueled stars

Hmm that means another online shopping session for chemicals.

[Potassiumchlorate]

In larger amounts over-fueled flash compositions react much more violently, especially with a catalyst.

[psyco_1322]

Lancaster covers the sensitivity of flash powders in his book, it relates to sensitivity to impact and also the advantage of adding graphite to reduce sensitivity.

 

The tests were carried out using the Rotter impact test, which uses the following scale:

 

0-30 Very sensitive

30-90 Sensitive

90+ Insensitive

 

from tests carried out the following results were obtained:

 

KCLO4 37% / Mg (fine) 57% / graphite 6% - sensitivity of 70

 

KCLO4 66% / Al (pyro grade) 34% - sensitivity of 58

 

KCLO4 60% / Al (pyro grade) 38% / graphite 2% - sensitivity of 78

 

BaNO3 68% / Al (pyro grade) 23% / sulfur 9% - sensitivity of 66

 

 

Lancaster then states that "devastatingly the Chinese mixture of potassium perchlorate 45%, sulfur 15% and magnalium 40% could be as low as 20 as a result of the hardness of the magnalium particles. It may well be that the presence of sulfur sensitises the mixture"

Lancaster does not include any data on 60/40 KCLO4 / mgAl flash however.

 

Well I haven't read Lancaster's book, though I would like to sometime. If those are the only things he tested, that was kind of a waste, too many variables, formula changes, and other things. Kind of like the Shimizu thing about getting flash to detonate. Seems like people just mixed random things and tested them with no laid out plan to figure something us full out. Not trying to bash anyone, just my thoughts, probably help if I had read the texts too.

Edited June 2, 2012 by psyco_1322