Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
Author: Subject: Sound Emission: Flash Powder vs High Explosives
akkustz
Harmless
*




Posts: 1
Registered: 27-2-2019
Location: Germany
Member Is Offline


wink.gif posted on 29-1-2022 at 06:42
Sound Emission: Flash Powder vs High Explosives


Well this is my first post, short introduction: I am interested in energetics but have not much experience besides flash powder. I also love everything that is loud rather than destructive. I have never experienced some high explosives going off in person so my assumptions on them are purely influenced by what i read here and elsewhere.

There are somewhat similar posts already so i hope i'm not a duplicate, but i wanted to share my thoughts on this a bit ;)

Question: Does Flash powder beat high explosives in sound emission? (Flash powder being the standard 65:35 Perchlorate/Aluminum mix)
More precisely: If someone was crazy enough to build a 10kg flash powder firecracker would it outperform 10kg of a high explosive?

I read different high explosives are better and worse at creating acoustic energy. Also the frequency contents in the boom make it seem louder or quieter even though quantitatively it has the same loudness in decibels.
Many decibel measurement devices come with a dB(A) Weighting which accounts for our human ear and adjusts the value based on its frequency contents.
Someone should do a huge collection measurement-tests with many different explosive devices, given they have permits and can just do it :D

-- Why is this information useful?
If handled properly, flash powder is not dangerous. But the danger increases gradually as the weight you're working with increases. A very small spark can ignite the whole thing. And in some circumstances big quantities can detonate* on you. But burns are already bad enough.
I myself would not go anywhere above 30 or 40 grams. During the mixing process most accidents occour.

* Not sure if it actually does detonate as I have no way of determining that but it can produce a really loud bang without confinement, if you have a bigger quantitiy.

High explosives on the other hand are pretty safe to handle in large quantities, but their production is relatively hard in contrast to flash powder. And making a detonator can be quite challenging without much resources. And also quite a bit more illegal i suppose?
Well how you get your hands on them should not be the main focus of this thread :D
View user's profile View All Posts By User
katyushaslab
Hazard to Self
**




Posts: 81
Registered: 19-1-2021
Member Is Offline

Mood: precipitating

[*] posted on 29-1-2022 at 12:05


Lower velocity explosions tend to be audible further away.

If I recall correctly, the reason for this is to do with how lower frequency sound waves travel further.

Eg: you have an asshole neighbour who plays loud music at night. Up close, you can hear it clearly. Further away, you only hear the bass tones.
View user's profile View All Posts By User
MadHatter
International Hazard
*****




Posts: 1246
Registered: 9-7-2004
Location: Maine
Member Is Offline

Mood: Enjoying retirement

[*] posted on 30-1-2022 at 00:09
Flash Powder


The industry standard for flash powder is 70/30, KClO4/Al. As for high explosive the
BATFE classifies it as such because it can explode without confinement.

The power of most high explosives far exceeds flash powder. This is a link to a
website for comparisons:

https://en.wikipedia.org/wiki/Table_of_explosive_detonation_...

[Edited on 2022/1/31 by MadHatter]




From opening of NCIS New Orleans - It goes a BOOM ! BOOM ! BOOM ! MUHAHAHAHAHAHAHA !
View user's profile View All Posts By User
Dr.Bob
International Hazard
*****




Posts: 2430
Registered: 26-1-2011
Location: USA - NC
Member Is Offline

Mood: No Mood

[*] posted on 31-1-2022 at 11:07


I once saw about a 10 pound flash powder salute at the PGI. It was being used to test safety barriers by setting it off in a buried mortar tube behind a series of Jersey barriers. It made an impressive noise, from 1200 feet away, blew a hole about 10 feet deep and wide, and broke the closest barrier in half. None-the-less, I am pretty sure that most high explosives would have done more damage. Flash is somewhere between black powder (about 10x more powerful) and HEs, but is more practical in fireworks than HEs. Why the ATF combined both licenses, I still don't get.
View user's profile View All Posts By User
Tsjerk
International Hazard
*****




Posts: 2746
Registered: 20-4-2005
Location: Netherlands
Member Is Offline

Mood: Mood

[*] posted on 31-1-2022 at 12:18


I once heared 200 grams ANNM echo against a 7 meter dike 5 kilometers away, which took about half a minute. I don't think flash would have done that.
View user's profile View All Posts By User
MadHatter
International Hazard
*****




Posts: 1246
Registered: 9-7-2004
Location: Maine
Member Is Offline

Mood: Enjoying retirement

[*] posted on 31-1-2022 at 13:16
VOD Table


On the table in my previous post click on the "Detonation Velocity (m/s)" column
header to put it in ascending order. It starts with ammonium nitrate at 2700 and
ends with octanitrocubane at 10100. 6th down in the the list is "potassium
perchlorate aluminium mixture" at 4600. I was surprised at #12 - ammonium
perchlorate - 6300. Impressive. Probably needs a #8 cap to detonate.




From opening of NCIS New Orleans - It goes a BOOM ! BOOM ! BOOM ! MUHAHAHAHAHAHAHA !
View user's profile View All Posts By User
Dr.Bob
International Hazard
*****




Posts: 2430
Registered: 26-1-2011
Location: USA - NC
Member Is Offline

Mood: No Mood

[*] posted on 31-1-2022 at 13:36


Ammonium perchlorate can be quite unstable with many fuels and salts, so it does not surprise me a lot that it might be quite powerful, but just be aware that while there are a few star mixes that use it in pyro, there are also many mixtures that are not stable at all. That has caused a few accidents in the shell building world. But I was amazed at how powerful flash mixes can be, compared to even some strong explosives. But it is hard to find a good source of octanitrocubane for fireworks production...

Note that one you are working with more than a few ounces of flash, there is little additional hazard in working with pounds, as both are pretty lethal in a mistake. Even 50 g is enough to severly hurt or will you if it are near it.

[Edited on 31-1-2022 by Dr.Bob]
View user's profile View All Posts By User
MadHatter
International Hazard
*****




Posts: 1246
Registered: 9-7-2004
Location: Maine
Member Is Offline

Mood: Enjoying retirement

[*] posted on 31-1-2022 at 18:22
Rule Of Thumb


Losing "parts" because of flash powder. Some pyrotechnicians state that the
rule of thumb is 1 gram per finger - no pun intended. I've heard that the cost
of manufacturing ONC is more expensive than the value of gold on a weight
for weight basis. Probably the reason militaries don't use it.

[Edited on 2022/2/1 by MadHatter]




From opening of NCIS New Orleans - It goes a BOOM ! BOOM ! BOOM ! MUHAHAHAHAHAHAHA !
View user's profile View All Posts By User

  Go To Top