15 replies to this topic

[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 by cmjlab, 22 September 2023 - 08:16 PM.

[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 by kingkama, 23 September 2023 - 07:35 AM.

[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 by mx5kevin, 23 September 2023 - 01:37 PM.

[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]

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