Flash powder questions

[PillaDoubleG]

So I recently made some flash powder... and it was very crappy (at least I think so). I want to pose some questions, to see if I could improve on my flash powder the way I think it could be improved.

1. Should flash powder also be fast to get the wanted effect? (wanted effect is an explosion from a firecracker, for context)
2. Is it possible to get better, faster KNO3/Al/S flash powder using normal aluminum, not dark?
3. Is it possible to improve said flash powder using other methods (not including using different ingredients)
4. Is it safe to mix said flash powder in a container, the classic way, or is it too sensitive? Should I mix it using only the diapering or screening method?

This question isn't 100% related to flash powders, but it's still in that topic...
Is it possible to make dark aluminum, using a ball mill, when both the ingredients are already in a fine powder? And, if possible, how long should the 2 already fine powders be mixed for? Since all of the tutorials I've watched featured coarse aluminum, which means they had to mill their powder for at least week.
Also, what type of charcoal should be used for the production of dark aluminum?

Thanks again APC! Sorry for asking so many questions, but so far this forum has been a MASSIVE help!!!

[Guest]

…

 

Edited December 2, 2023 by Bbqjoe

[Zumber]

Yes Nitrate based flash works well for firecracker.

I would suggest stop thinking of ball milling aluminium powder on your own, for flash powder you will need extreme fine mesh grade aluminium. Instead of ball milling you would better purchase commercial fine mesh aluminium. Look for suppliers in your area.

For flash ball mill kno3 into fine powder (100 mesh). Mix kno3 and sulphur using screen two to three times then add aluminium using diaper method or zip lock bag method or using container.

Dont ever make large batch. And dont store flash powder for long time(prepare only as per your need).

[PillaDoubleG]

3 hours ago, swapnilsutar1988 said:

Yes Nitrate based flash works well for firecracker.

I would suggest stop thinking of ball milling aluminium powder on your own, for flash powder you will need extreme fine mesh grade aluminium. Instead of ball milling you would better purchase commercial fine mesh aluminium. Look for suppliers in your area.

For flash ball mill kno3 into fine powder (100 mesh). Mix kno3 and sulphur using screen two to three times then add aluminium using diaper method or zip lock bag method or using container.

Dont ever make large batch. And dont store flash powder for long time(prepare only as per your need).

Aha, I see. I already have a supplier for aluminum powder, but I don't have one for dark aluminum sadly. I will try your method that you mentioned. And another thing, should I add boric acid into the mix? I read that it increases shelf life. I obviously won't make more than 20 grams of flash at a time, but it might be a thing to consider.
 

4 hours ago, Bbqjoe said:

…

 

Sorry if I asked too many questions in one post, I didn't want to open up 20 threads for the same topic... 

[Zumber]

Look for flake fine aluminium finer than 400 mesh.

Boric acid prevents nitrate aluminium reaction in wet condition if water is to be added. For flash you are not going to add water also dont store flash for long time( so there is no issue of shelf life). You can add 1 percent if you wants too but its not necessary.

 

[Zumber]

10 minutes ago, swapnilsutar1988 said:

Look for flake fine aluminium finer than 400 mesh.

Boric acid prevents nitrate aluminium reaction in wet condition if water is to be added. For flash you are not going to add water also dont store flash for long time( so there is no issue of shelf life). You can add 1 percent if you wants too but its not necessary.

 

For shelf life Barium nitrate increases shelf life.

Barium nitrate 3000

Sulphur 1000

999 aluminium 1000

Following mixture is best for firecrackers. It aslo used barium nitrate.

Edited December 2, 2023 by swapnilsutar1988
spelling mistake.

[Arthur]

The whole idea of flash powder depends on having dust fine dark aluminium powder. If you can see a grain it's much too coarse. DO NOT try to make or mill aluminium to dust the process is pyrophoric -it burns fiercely without ignition sources. 

Once you find dark pyro aluminium, work small make only the amount of flash you need work in single gram quantities with scales that show decimals of grams. Nitrate flashes are a little safer than perc flashes. 

[MicroGram]

I've read on here a few times that Nitrate/Al/S (Slow Flash) is as or more sensitive then Perc flash. I don't recall seeing any explanation or empirical evidence (drop test values etc) but definitely something to keep in mind.

Here's a Skylighter article about general firework safety. About mid way through there is a section titled "What about Flash?" that has some basic and helpful information.

https://www.skylighter.com/blogs/fireworks-information/fireworks-safety-manual

 

[cmjlab]

I don't see nitrates listed as being "as" or "more" dangerous in that article. 

I can see why stability could be affected due to ability to attract moisture, and double displacement to form other chemicals which leads to decomposition in one form or another.

From the ignition point temperature alone, nitrate / AL combinations require greater energy input to ignite, which makes them not "as" sensitive as perchlorate and chlorate oxidizer compounds.  

However, I do agree that it is still a good idea to take all the safety precautions one takes with other oxidizer / metal / sensitizer combinations, when dealing with any of them.

[Zumber]

6 hours ago, cmjlab said:

I don't see nitrates listed as being "as" or "more" dangerous in that article. 

I can see why stability could be affected due to ability to attract moisture, and double displacement to form other chemicals which leads to decomposition in one form or another.

From the ignition point temperature alone, nitrate / AL combinations require greater energy input to ignite, which makes them not "as" sensitive as perchlorate and chlorate oxidizer compounds.  

However, I do agree that it is still a good idea to take all the safety precautions one takes with other oxidizer / metal / sensitizer combinations, when dealing with any of them.

is there any additive that can acts as neutralizer (Barium carbonate?) during storage of nitrate based flash. I have never had issue of handling nitrate based flash powder so far. Nitrate based flash is safer than Perchlorate and chlorate based in terms of static electricity impact and friction IMHO. Still every flash must be treated with respect..!!

[Soloserly]

Just for perspective - I've read that the flash/bang grenades used by SWAT teams use 5 g. of perc flash powder.  10 g. confined can easily remove body parts.  Using a long fuse, I lit an unconfined pile of around 3 grams that had spilled on the ground outside, and someone 1/4 mile down the road said they thought lightning had struck nearby.  I echo what Zumber wrote: every flash must be treated with respect.  

[PillaDoubleG]

On 12/3/2023 at 1:12 PM, Arthur said:

The whole idea of flash powder depends on having dust fine dark aluminium powder. If you can see a grain it's much too coarse. DO NOT try to make or mill aluminium to dust the process is pyrophoric -it burns fiercely without ignition sources. 

Once you find dark pyro aluminium, work small make only the amount of flash you need work in single gram quantities with scales that show decimals of grams. Nitrate flashes are a little safer than perc flashes. 

There is a source I could buy dark aluminum from, so It's 99% likely I'll just order it from there. But I've seen other content related to aluminum powder, and it doesn't seem that it's THAT dangerous, still not to be played around with. Aluminum or dark aluminum powder itself is not horribly dangerous, but the second you mix it with an oxidizer, it becomes horribly dangerous.

[MicroGram]

On 12/3/2023 at 2:23 PM, cmjlab said:

I don't see nitrates listed as being "as" or "more" dangerous in that article. 

I can see why stability could be affected due to ability to attract moisture, and double displacement to form other chemicals which leads to decomposition in one form or another.

From the ignition point temperature alone, nitrate / AL combinations require greater energy input to ignite, which makes them not "as" sensitive as perchlorate and chlorate oxidizer compounds.  

However, I do agree that it is still a good idea to take all the safety precautions one takes with other oxidizer / metal / sensitizer combinations, when dealing with any of them.

 

On "Here" meaning the forum. Not the article, which I thought just had some basic helpful info.

a quick search for slow flash or better yet a google search with the APC tag will reveal the threads I was referring to.

https://www.google.com/search?q=site%3Awww.amateurpyro.com+slow+flash&sca_esv=588105669&biw=1920&bih=886&sxsrf=AM9HkKkTBXm6NeN6a2XXoEkcW9Epd3GW5g%3A1701808941546&ei=LYtvZaz6IMub0PEPlJ2jkA8&ved=0ahUKEwjsxL6rlPmCAxXLDTQIHZTOCPIQ4dUDCBA&uact=5&oq=site%3Awww.amateurpyro.com+slow+flash&gs_lp=Egxnd3Mtd2l6LXNlcnAiI3NpdGU6d3d3LmFtYXRldXJweXJvLmNvbSBzbG93IGZsYXNoSPTuEVAAWABwB3gAkAEAmAE5oAE5qgEBMbgBA8gBAOIDBBgAIEGIBgE&sclient=gws-wiz-serp

Also I thought it was the other way around? Nitrate comps being easier to ignite then Perc based?

Maybe someone could shed some light on this

 

Edited December 5, 2023 by MicroGram

[cmjlab]

It'd take me too long to read all those, I'm not that interested, thanks though.

KCLO3 (in the comps/ratios to fuel and sensitizer we often use) requires less energy to ignite than most KNO3 comps we use, but also is of more risk due to the ease of starting its energetic reaction in combination with a fuel, and even more sensitive when combined with sulfur (though not unusable).  But I don't know that it's actually a logical comparison to KNO3 comps.

id generally agree that KCLO4 often requires more energy to ignite, than KNO3, in the common pyro comps we use, though it's still like comparing apples to oranges.

Sulfur reduces the ignition points of all 3 oxidizers, so it would depend on if you're talking about straight 70/30 oxidizer to fuel, with all 3 oxidizers and all other variables being the same (as that measurement of energy would look different from trying to compare SFB to normal 7:3 to KCLO3 based formula). 

Though, this is probably a conversation better for the chemistry section, as it deviates from the original subject.  

**Also off topic - Id also still be curious about my question related to what you posted in the safety section, regarding Hemp Charcoal and the exploded mortar**

Edited December 6, 2023 by cmjlab

[cmjlab]

My brain is not functioning quite right as of now, I'll have to re-tackle the wording on my post above tomorrow...... After I've got some sleep 🙂

Edited December 6, 2023 by cmjlab

[MicroGram]

Ahh no worries!

Just happened to find this tonight in The Fireworks, Art, Science & Technique, Shimizu, pg 319.

Impact Info, not thermal but I thought was interesting nonetheless!

 

Edited December 6, 2023 by MicroGram

[Soloserly]

On 12/5/2023 at 9:04 PM, MicroGram said:

Ahh no worries!

Just happened to find this tonight in The Fireworks, Art, Science & Technique, Shimizu, pg 319.

Impact Info, not thermal but I thought was interesting nonetheless!

 

VERY interesting!  I have to wonder what "NON-explosive height... 50 trials" means?  Does that mean they dropped a 2 kg. hammer on it 50 times per composition, and that's the drop height at which it repeatedly DIDN'T explode?  Would that mean that going one cm higher is the height at which it consistently DID explode?  

If that's the way they tested it, that's more than 15,000 hammer drops!

[redbullzuiper]

 

The nitrate firecrackers consisted out of KNO3 and Ba(NO3)2, strontium nitrate wasn't included. I think strontium nitrate is less sensitive than either barium and potassium nitrate.

Edited December 16, 2023 by redbullzuiper

[Zumber]

From where you got this chart?

[GoldenStars]

On 12/16/2023 at 1:41 PM, redbullzuiper said:

 

The nitrate firecrackers consisted out of KNO3 and Ba(NO3)2, strontium nitrate wasn't included. I think strontium nitrate is less sensitive than either barium and potassium nitrate.

From which book/source did you get this from?

[Soloserly]

On sciencemadness.org check out "Safety Study of the Chlorate Firecrackers"

[Zumber]

The samples used in test contains sulphur in it.

I am confused about perchlorate sulphur and aluminium powder flash mixture has only 20 percent chances of impact test.

I will consider its probablity will be higher than 20 percent due to sulphur.