Magnesium based flash powder not "making a bang"

[print118]

I have been experimenting with 300mg of a potassium perchlorate and magnesium based flash powder, but I'm a bit stumped on why it isn't, or rather is, making a bang. I've made it a few times, but it has not exploded, only making a bright flash of light. Though this one time it did explode with a loud and deep report. Question is why?

 

I didn't change the amount of mix or the percentages or the amount. The only thing that has changed is maybe the humidity of the air and time of day, nothing else. I've tried replicating the bang, but have not been successful as of now. Changing percentages or amount did not make a bang. Maybe someone here can shed a bit of light on this?

[Arthur]

Mesh size would be my first thing to check, but first of several.

[Crazy Swede]

The intimacy between ingredients is very important when using loads as small as 0.3 g. How did you mix it?

 

Was it loose heaps or confined inside a casing? If loose, ignition can vary a lot if ignited from a fuse. Sometimes causing self confinement and sometimes not.

[print118]

The intimacy between ingredients is very important when using loads as small as 0.3 g. How did you mix it?

 

Was it loose heaps or confined inside a casing? If loose, ignition can vary a lot if ignited from a fuse. Sometimes causing self confinement and sometimes not.

 

Mixing was done by adding both chemicals to a paper muffin cup and shaken around and rotated around for about a minute. I'm not sure how well this mixed them together, but they looked mixed.

 

The powder was loose in a small parabolic shaped plastic cup and was tapped on the table to spread the powder evenly. The parabolic shape increased the height the powder reached to about 1cm from top to bottom, if that matters. And ignition was done via a NiCr wire placed at the bottom of the plastic cup and heated with some current.

 

Any idea what makes self confinement sometimes happen in this scenario? If possible I would like to basically remove the possibility of it self confining, maybe adding a inhibitor or something?

 

 

 

Mesh size would be my first thing to check, but first of several.

 

Maybe the particle size was randomly smaller than usual, which caused the bang? Not sure though, since I haven't been able to replicate it.

[MicroGram]

Any idea what makes self confinement sometimes happen in this scenario? If possible I would like to basically remove the possibility of it self confining, maybe adding a inhibitor or something?

Why not just use a slower comp? BP?

[kingkama]

Auto confinement happens only in few grams pile, something near the ounce, a woof o pouf is the max you Will obtain in so small quantity. As said before the mesh size of oxidizer and fuel Is mandatory,

fuel size:

Al less than 25 micron

Mg less than 45 micron

MgAl less than 30 micron

Oxidizer

All less Is possible May be good under 40 micron.

Stay alert mg flash Is very reactive.

[print118]

Why not just use a slower comp? BP?

 

I'm looking for a really bright flash of light, so BP isn't an option. Magnesium flash powder is what came to mind.

 

 

 

Auto confinement happens only in few grams pile, something near the ounce, a woof o pouf is the max you Will obtain in so small quantity. As said before the mesh size of oxidizer and fuel Is mandatory,

fuel size:

Al less than 25 micron

Mg less than 45 micron

MgAl less than 30 micron

Oxidizer

All less Is possible May be good under 40 micron.

Stay alert mg flash Is very reactive.

 

So are you saying that the bang that was created was due to a smaller particle size? And the other ones didn't make a bang because their particle size was larger by chance. It could be since I'm not sure on the consistency of the perchlorate particle size, I haven't even measured it.

[chuckufarley]

What does your Mg look like? It could be fairly severely oxidized, especially on the top layers where its exposed to the oxygen in the air. If you made multiple batches it could be that you got some less oxidized Mg that was more reactive from the bottom of the bag. With that small of a particle size, it doesn't take much to oxidize Mg to near uselessness.

Just my$0.02

[cmjlab]

I'm confused.

 

What exact effect are you trying to make, for what purpose?

 

What made you choose magnesium Flash powder? Is it actually "Flash Powder", or is it a "Photo Flash", or some type of star that produces a bright light like a flare type star?

 

You don't see a lot of magnesium Flash being used now, unless it's a "photo flash" or some hyperflash comp for breaking small inserts or crossettes.

 

What composition are you using?

What mesh Magnesium are you using?

- What type? (Granular, spheroidal/atomized, etc.)

- Have you treated the Magnesium?

- Is it humid where you live?

- Do you keep it in a sealed container, or has humidity made it in?

Where did you get the Potassium Perchlorate?

- What mesh was it when you bought it?

 

Hard to know how to respond without knowing some more of the above questions.

 

If you are just burning it in a loose pile, it's hardly a consistent repeatable process/method. It could have been that the one time that it made a loud noise-it was just mixed better. Or one of the other scenarios listed in responses above. *Edit* (added) Or could have just been packed in more the other times, and just fluffy enough the one time to allow rapid deflagration....

Edited September 23, 2023 by cmjlab

[kingkama]

 

I'm looking for a really bright flash of light, so BP isn't an option. Magnesium flash powder is what came to mind.

 

 

 

 

So are you saying that the bang that was created was due to a smaller particle size? And the other ones didn't make a bang because their particle size was larger by chance. It could be since I'm not sure on the consistency of the perchlorate particle size, I haven't even measured it.

Yes Is the only why!Smaller particle louder report, also for a photo flash you Need to use much fuel than oxidizer for enhance the termal output so the light emission.

Edited September 23, 2023 by kingkama

[Arthur]

Magnesium photoflash was used in WW2, Mg was ignited and pushed into the air, burning in air to completion. However it was used in hundred kilo batches- such are the needs of war.

 

First consider all the options for formulae. The flash used in the entertainments industry is usually more like the pyro sector calls slow flash, probably no magnesium. The problem with magnesium is that it forms a stable and protective oxide layer over time.

[mx5kevin]

The magnesium powder must be coated with 5% boiled linseed oil (what dissolved in small amount of white spirit) and completely dried at room temperature at several days spread out thinly to get a hard strength coat. See Takeo Shimizu Fireworks: The Art, Science, and Technique for more details. The Mg powder must be minimum -325mesh fine. And the KClO4 must be the possible finest too and completely dried moisture free. If the Mg powder are not coated (freshly made example from boiler anode), if the composition is freshly used, the difference is still noticeable. It is most effective with 20 micron home made magnesium powder. Magnesium powder is easily go bad oxidized when exposed to air, especially if uncoated. Therefore, it must be stored in an airtight bag. Uncoated Mg when mixed with KClO4 the composition is completely damaged in a month. And this is the minor problem, because in the worst case, during storage, it can catch fire spontaneously when mixed with the oxidizer, especially if the oxidizer also contains bound moisture and the ambient temperature reaches 40°C. Magnesium is a delicate substance that is strongly damaged by all environmental substances, even the air. KClO4 with Mg too much sensitive for friction compared with aluminum, or a KNO3, Ba or Sr(NO3)2,/Mg. It's too risky to work with it. The danger of unexpected ignition while working with it is too big. In small quantities, in small products, a much faster flash can be made from compared with aluminum. In larger products, the light is almost zero because the magnesium particles burn too quickly. Not a photoflash powder by any means, just the opposite. If someone can buy 3-11 micron any brand dark aluminum, it's not worth the risk even in a small amount. With 10% sulfur KClO4 with dark aluminum are much more better with the dark aluminum than the Mg. Much more brighter, safer, have the same power. Magnesium has an advantage when someone cannot purchase professional chemicals and prepares the powder himself, and even then only for small batches and small products. The reason for this is that it already works at a fineness of 40 microns compared with aluminum what need cc 7-11 micron for the same result. Who don't have a ball mill, can't make large quantities of quality aluminum at home. Even small quantities require special tools, a lot of work. What does not have this problem in grinding, refining is 50:50 magnalium alloy. This is easy to powder soft alloy, in a larger size it has a strong light, combines the advantages/disadvantages of aluminum and magnesium in a smaller size. You can work with this alloy in larger quantities, but it is not as safe as working with aluminum. If someone has professional chemicals, it's not worth dealing with KClO4/Mg maximum a Mg/Al 50:50 alloy.

[mx5kevin]

 

I'm looking for a really bright flash of light, so BP isn't an option. Magnesium flash powder is what came to mind.

 

 

KClO4/Mg a choice that is least suitable for this. This is a choice that the opposite can be said if fine magnesium are used.

 

A good and energetic photoflash powder composition:

 

30 KClO4

30 Ba(NO3)2

30 Al Dark 3-7 micron+Blue Aluminum (30 micron) 50:50 mixture (coated 2% Boric Acid H3BO3 what dissolved and dried)

10 Sulfur S

 

If pure Dark Al are used the composition will be much more less effective in a larger size.

 

Compared with pure KClO4 the effect last longer, brighter and more visible but smaler.

 

Try a KClO4/Al/S 50/40/10 with pure dark and 3-7 micron+Blue Aluminum (30 micron) 50:50 mixture (does not need to use boric acid here). Much more energetic than the Ba(NO3)2 version, the visual effect are much more huger but less visible. The use of blue aluminum is noticeable in effects above 10g, but very spectacularly there. The coarser, heavier particles that burn in the air give the big visual effect. But it doesn't work without the fine metal powder because it provides the energy. Under 10g effects with pure Dark Al the proportion rich in metal powder is advantageous from several points of view.

 

Both recipes work with 325 mesh 50:50 40 micron but not finer/coarser magnalium Mg/Al alloy what coated with linseed oil.

 

Both recipes combinating the photoflash powders effects with high power.

Edited September 23, 2023 by mx5kevin

[mx5kevin]

Check my KClO4/Mg/S flash from homemade magnesium, and the steel plate bar stamp process. The point is in the details. The various videos have information about everything essential. Making a high quality flash powder are a complex process properly dried and powdered, mixed, coated ingredients all step matter. There are huge differences in performance based on the method of preparation. Not fine enough for the composition all the ingredients, the oxidizer are dried and extremely finely powdered, the metal powder are protected (coated if required), but even when mixing, the most homogeneous consistency must be achieved. And this cannot be achieved by simply shaking the powders together. This can only be achieved by gently stiring the flash between two surfaces, with serious security measures. Then the metal powder and the other ingredients are mixed in such a way that it becomes a gray powder in which the dominance of the metal powder disappears visibly and the powder will be more compact. But the basis of everything is metal powder of the right fineness. The minimum requirements for flash powder with homemade metal powders from aluminum minimum 20 micron (3-11 micron if purchased for the purpose), from magnesium and magnalium minimum 400mesh 40 micron. Refinement of metal powders at home is only possible with special tools and a hard slow work. Without this mesh sizes, it will be slow, it works like a termite, the fact that someone tried a flash combination with some kind of fine metal powder, by changing the metal powder particle size parameters with the same proportions, a completely different result can be achieved. If someone has metal powder of the right fineness, how they prepare it the flash powder from it also makes a huge difference.

[mx5kevin]

Inadequate cover, raw material of inadequate quality, compressed flash powder, small details and many mistakes can made. Anyone who does not practice making a specific product for years will not be able to do it well. If someone make a product regularly, there is a huge difference between making a product a year or have five years experience. If the flash powder not loose textured and uniform density in the tube than will be not work. The flash powder was tapped on the table to spread the powder evenly, this results in dust compaction, which must be avoided. It must be sprinkled loosely into the tube and must not be tapped or pressed. It is worth sifting the flash before loading. If you have a well-made, high-quality flash powder, there are many ways to unprofessionally make a product from it. The adhesive material, the thickness of the wall, the material of the paper, the compactness of the wall, the end plugging, everything matters. KClO4/Mg is one of the strongest flash powders. This thing should work even in the case of KNO3/Mg or Ba(NO3)2/Mg, which is much weaker than this. It is much cheaper and easier to learn with the latter. As long as this does not work well, it is unnecessary to experiment with KClO4.

[cmjlab]

...

[print118]

Wow, a lot of responses right when I was away, how convenient . Some of you have asked some similar questions, so I will answer them at once.

 

What do I want to achieve?

- The goal is to have a flash powder or I guess "photo flash" now, which when ignited will produce a very bright light, comparable to the sun or a flashbang or something similar. But I only want the flash part, not the bang. The mix should also be "easily" ignitable electrically with some NiCr wire, while preferably not being too sensitive to friction, although that may be difficult to achieve. The main point though is the bright flash and no loud bang, while being sensitive enough to ignite with some NiCr wire, but not too sensitive at the same time. If there are better mixes than potassium perchlorate and magnesium, like some of the aluminum mixes, then even better, but when I tested potassium perchlorate and dark aluminum 4um, it didn't ignite from the heat of the wire. Maybe it would with the sulfur though.

 

How did I make the potassium perchlorate and what is the mesh size?

- The potassium perchlorate was self-made via electrolysis, purified, dried in the oven for a few hours and then grinded by hand to a pretty fine powder with vigorous grinding, it's so fine that it easily goes flying like dust. Exact mesh size is unknown though.

 

What type of magnesium powder is it and how is it stored?

- The magnesium was bought online and claims to be <40um, so 40um max and below. Type of magnesium is not told, so I don't know whether it is spherical or atomized, but it looks like a fine powder and also goes flying of as dust quite easily. It also claims to be "stabilized" magnesium, but nowhere do they say how it has been stabilized. I have contacted them about the type and stabilizer, but it may take time before they answer. I however have not treated it in any way and just keep it stored in the airtight bag it came in. I have attached some images of the magnesium.

 

Current mixture

- The mix is 50:50 by mass, but I noticed that 70:30 oxidizer rich led to a bigger bang, so maybe the fluke charge that exploded had more oxidizer in it than there should have been. This is quite possible, since when working at these small scales the accuracy of my scale may come into question.

 

 

 

So what I'm getting here is that the explosion could have been caused by a multitude of reasons like inadequate mixing resulting in a non-homogenous mixture, varying particle sizes leading to more or less aggressive reactions, or anything else really. My method of mixing also seems to be insufficient, since the results of the mixing may wary, I many not get the same proportion of chemicals due to small amount and accuracy of my scale or mix it worse some times.

 

I also have some returning questions, like what powder mix could be better? I currently have access to sodium/potassium chlorate and perchlorate, magnesium powder <40um, 4um Dark Aluminum, 50:50 magnalium <45um. I don't have easy access to nitrates to making barium nitrate or even getting would be problem. I can by nitric acid to try and make it, but only in 3% concentration so making salts with it could be slow, though if the barium nitrate is really good then I guess it could be worth the effort to get the brightest flash. Sulfur I can also buy easily.

 

I've heard that barium nitrate is really good for brightness, since it radiates in the visible spectrum, but still access to it is going to be limited. These things in mind, should I try a different mix, like the one proposed by mx5kevin? I'm looking for the brightest and "safest" mix, which can be stored for some time and not too sensitive.

 

Thank you all for your responses by the way, they have been really insightful!

 

 

Normal and macro images of the powder:

 

[mx5kevin]

The goal is to have a flash powder or I guess "photo flash" now, which when ignited will produce a very bright light, comparable to the sun or a flashbang or something similar. But I only want the flash part, not the bang.

 

KClO4 based flash powders have extreme loud sound. If the point only the bright light without a loud bang barium nitrate with aluminum and some sulfur are the one of the best illuminating bright flash with white light (need to coat with 2% boric acid the aluminum). Have much more brighter light than magnesium with Ba(NO3)2.

 

60 Ba(NO3)2

30 Al (Dark 3-7 micron) or mixed Blue+Dark 50:50 (+2% Boric Acid H3BO3 for the aluminum coating important)

10 Sulfur S

 

A fast ratio. With Blue Al+Dark 50:50 are the effect are similar than Dark Al. The best illuminating white bright fast photoflash without extreme power what i know. I tried all possible flash powders from all popular oxidizers. You will be hard-pressed to find a brighter white light composition than this.

[Richtee]

That powder’s no where near fine enough. But with sufficient oxidizer (read excessive) and a bit of finer may produce the desired effect.

[cmjlab]

Some thoughts on photoflash -

1. To me, your metals looks like stuff I have classified as mainly ~100-150 mesh, with some particles as large as

~60-80 mesh. Of course that is pure speculation based on the photos and powder appearance.

2. The photoflash may be quiet in a loose pile, but if you intend to use it in a shell (as an insert) it will make noise - just not as much as normal flash.Even theatrical flash pots have a loud bang.

3. Barium appears (*edit - clarified wording*) the most in photoflash comps that are trying for the brightest light output, then sodium nitrate / magnesium seems to appear as another popular one for MILSPEC comps. Almost all contain Magnesium though.

4. No matter how you go about it, or what formula you choose, you will have to tweak it to work the way you want with your metals and particle size (IMHO - those two factors play the largest role in end result, followed by containment).

 

---------

Photoflash Without Barium Nitrate

---------

This method / composition is from a reputable and trusted source (TR). It doesn't need Barium, but WILL need KN03. Aside from that, you can get it to work with what you have with testing.

 

*The key factor here is a functional starting point to which you can adjust your fuels / oxidizer ratio to adjust for what your end goal is. TR says you can use all Magnesium, all Aluminum, or different combinations of the two (but you'll have to test/tweak).

 

*Will require you to keep the amount of containment tothe minimum needed to survive your end goal for the photoflash, in order to avoid excessive noise.

 

Link to formula for TR's Photoflash Composition

https://www.fireworkscookbook.com/firework-recipe/photoflash-powder-trs/

 

7.5 - KN03

7.5 - KCL04

42.5 - Mg/Al 200 mesh

42.5 - Magnesium 200-325 mesh

 

YouTube Video of Test Batch

https://www.youtu.be/v6TgaP1HZZg

 

---------

Normal Photoflash

---------

Military Spec Photoflash - Requires Barium Nitrate

Link: https://www.amateurpyro.com/forums/topic/14251-really-slow-photoflash/

 

---------

Alternative Possibilities to Photoflash

---------

 

1. Addition of woodmeal to 70/30 creates Photoflash effect.

- Link: https://www.amateurpyro.com/forums/topic/5026-photo-flash/

- It's suggested that woodmeal added to regular (70/30) creates a photoflash (*I have not tried this* ).

- This method would not ignite easily with NiCr but you could swap the 70/30 with Thunder #3 (Shimizu's F.A.S.T.) which may work better due to the addition of sulfue to decrease ignition temp (but also *increases sensitivity*)

- Page 2 has the original information outlined by the person suggesting it. https://www.amateurpyro.com/forums/topic/5026-photo-flash/page-2

 

2. Use flare or flare star comp as starting point to make photoflash.

Edited September 29, 2023 by cmjlab

[print118]

I've heard a lot of good things about barium nitrate based photo flash mixes, but the problem is that I can't really get any. But I can make some, since I can buy nitric acid in low concentrations ~3%. Problem with making the nitrate though is the loss of about half the product, since the water content of the nitric acid is so high and barium nitrate still dissolves in water pretty well, about half of the barium nitrate stays in solution at 0°C. Now I could concentrate the nitric acid, but I don't know about that and I currently don't have a functional lab hotplate or the glassware for distillation. Although I could still try to make it and compare it with my current mix to see if it would be worth it. What do you guys think?

 

The sawdust photo flash also looks pretty good, I might try that and see what it looks like. Though it might impact the brightness too much, since my charges work at the 300mg scale. But for bigger ones it apparently might make the flash longer.

 

I was thinking about using sodium perchlorate as an intermediary, between the brightness of barium and the ease of making perchlorates. I've heard that sodium salts are very bright in their own right and would be brighter than my current potassium perchlorate and magnesium mix, when swapped with the potassium. Only problem really, is that it is quite hygroscopic so working with it won't be as simple, especially on a humid day.

Barium appears (*edit - clarified wording*) the most in photoflash comps that are trying for the brightest light output, then sodium nitrate / magnesium seems to appear as another popular one for MILSPEC comps. Almost all contain Magnesium though.

Also you mention that sodium nitrate is commonly used in high brightness photo flash compositions, so what about sodium perchlorate? Is it worse or better in some regard?

 

And regarding using aluminum or magnesium in photo flash mixes, what's the difference between them? Is it mainly the sensitivity or does one radiate in the visible spectrum more than the other?

[cmjlab]

Sodium nitrate is commonly used in flare stars, not flash. I don't believe it's energetic enough for most people's purposes. I was just saying if you had it, you might look at some of the flare comps to see if you could spice it up to work as a photoflash.

 

Sodium perchlorate would be to hygroscopic to be useful.

 

Sodium nitrate is also hygroscopic, but from what I've seen, can be managed as long as you keep moisture sealed out of it.

[cmjlab]

Mg/Al is more reactive than Aluminum, it retains some of the energy of magnesium by using a portion of Al to replace a portion of magnesium, to tone down the sensitivity. So Mg/Al is less likely to react with water than straight magnesium, yet still burns a bright white like magnesium (just not AS bright).

 

Aluminum is cheaper. Maybe someone else will weigh in on other benefits of Aluminum over Mg/Al. I believe to that AL being less reactive also works well in glitters, as it does not ignite and burn up immediately in the flame from the star (unless you are using a fine flake Al of course - that burns just fine).

[print118]

Sodium perchlorate would be to hygroscopic to be useful.

 

The current plan would be to store the final mix in a plastic charge, with an aluminum foil cap, so there wouldn't be much containment, but should protect from moisture. Would this work for the perchlorate?

 

 

I was also thinking of a barium nitrate and magnesium mix, shouldn't this be brighter than the one using aluminum that mx5kevin suggested:

 

KClO4 based flash powders have extreme loud sound. If the point only the bright light without a loud bang barium nitrate with aluminum and some sulfur are the one of the best illuminating bright flash with white light (need to coat with 2% boric acid the aluminum). Have much more brighter light than magnesium with Ba(NO3)2.

 

60 Ba(NO3)2

30 Al (Dark 3-7 micron) or mixed Blue+Dark 50:50 (+2% Boric Acid H3BO3 for the aluminum coating important)

10 Sulfur S

 

A fast ratio. With Blue Al+Dark 50:50 are the effect are similar than Dark Al. The best illuminating white bright fast photoflash without extreme power what i know. I tried all possible flash powders from all popular oxidizers. You will be hard-pressed to find a brighter white light composition than this.

[cmjlab]

My understanding (I've no personal experience with sodium perchlorate), is that it is deliquescent (not just hygroscopic), meaning it is not just likely to absorb and retain moisture from the air - its more likely to turn into a soupy liquid, even in low humidity environments (I believe it's as low as ~20%, but don't quote me).

 

Again, I'm not a chemist by any means,but I did stay at a Hilton! :-). That is just my understanding of why it isn't used for pyro, with maybe the exception of using it for double displacement to produce potassium perchlorate or ammonium perchlorate possibly.