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G'day All!


I have only been on this forum for a very short time and I love it. I have been strongly interested in pyrotechnics (especially wanting to make my own) for ... well, it's a part of me.


Anyway, I actually know very little about display fireworks. Words such as 'cake', 'ball' and 'mortar', while i know one meaning...


(what makes 'whistle mix' whistle?)


so, can you give me a few links or some books I should read? Thanks muchly.





Just found TurboPyro. Downloading now.


Edited by Nikko
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There is a pretty good post in the chemistry section that you may find helpful.




This post is pretty comprehensive but by no means all inclusive. It contains a list of common pyro chemicals and terms. This site is a great resource. Many of the members are very intelligent and have spent hundreds and hundreds of hours learning their trade. Read as much as you can and always verify things before trying them. This is a fun and fulfilling hobby but it can also be extremely dangerous if you don't do your research or your sources aren't valid.

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A ball shell is shaped like a ball, and this style of shell originated in Asia. They lend themselves to perfectly round bursts. This is the shell you most commonly see in a public display in the United States these days.


A cylinder shell is shaped like a cylinder. This is the Italian, Maltese, and Italian/American type shells. They tend to give oblong shaped breaks, but are well suited for carrying inserts and being stacked for multibreaks.


A cake is an item that contains multiple shots in separate tubes and fused together from the bottom. The shots can be comets, mines, shells, or shell inserts.


A mortar is the tube the shell is shot out of. Usually made from HDPE, fiberglass, cardboard or steel. Steel is reserved for heavy multibreak shells which generate high pressure at lift. It is incredibly dangerous if the shell breaks in a steel mortar and appropriate precautions need to be taken. Under NO circumstances should you attempt to use PVC pipe as a mortar.



As to what makes whistle mix whistle, I am not sure if that is fully known to us mere mortals. Maybe someone else knows, but I don't.

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(what makes 'whistle mix' whistle?)


“Sounds” are produced through the rapid expansion of gas and generation of pressure waves:

1)Rapid heating of the ambient air by a confined composition

2)Rapid gas generation by the composition itself

3)Sound can be in the form of a pop/boom/ crackle or “whistle”



1)Just like when a person whistles, forced air through a small opening generates a whistle sound

2)Potassium beznozate + KClO4 = lots of CO2 and H2O generated rapidly (but not too rapidly)

3)Composition is pressed into a suitably sized tube (larger diameter tubes tend to deflagrate/detonate)

4)Whistle reactions are prepared to be on the verge of, but not actually, explode – very careful!

5)A whistle composition is actually burning intermittently from layer to layer in a pressed composition, and the pitch will drop as the composition burns down and a “longer” tube is left

6)Other fuels: Gallic acid, sodium salicylate.

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Whistle mix will whistle or "chirp" when a pinch is burned unconfined. It also does not need a smaller opening to produce the whistle like when a person whistles. The whistling in a pyro whistle comes from something else in how the fuel burns. The cored sections don't seem to whistle very much either and different catalysts change or kill the whistling sound.


The only resources I have that describe why whistle whistles, is Pyrotechnica XI and FAST.


In Pyrotechnica XI, the author states:


According to Shimizu's opinion, the whistling phenomenon comes from an alternative oscillatory reaction of burning and detonation, producing sound. Therefore the whistling composition must be sensitive to some extent -- not too sensitive and not too insensitive.


In FAST, Dr. Shimizu mentions some forumulas for whistles, but does not get too deep into the science behind it. I am sure there are other texts that address this, but I do not own them to look through.


I will also add that Galic acid and Potassium Picrate are particularly sensitive compositions. I know a couple of well accomplished pyros what won't touch the stuff, and they aren't afraid of using "standard" sensitive mixtures. That's enough for me to stay clear.

Edited by nater
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