Smoke Shells

[Bearark]

Heyas all,

 

 

I used the search function and couldn't find much so here goes,

 

One of my dream projects is smoke shells, both shells that eject smoke stars and parachute shells that have a smoke device that burns slowly as it descends to earth. I recall seeing something about Japanese parachute shells in "Pyrotechny"(Could have been somewhere else it was years ago) but was wondering if anyone could give me any advice on constructing these or point me in a direction where I could find more on it.

For the parachute shells my main concern is fire danger, Awhile back I had purchased commercial parachute flares and half of them, well the parachute didn't work so well. Is there a cooler burning smoke composition I could use for this ? Or should I abandon the parachute shell idea all together and just stick with smoke stars ?

As for the smoke stars is there any recommended compositions to use ?

 

 

Thanks so much for all the input and I apologize if this is too newbish to ask

Edited May 31, 2010 by Bearark

[Dr Boom]

Bearark,

 

I don't think your post was newbish nor inappropriate. New questions are welcome when presented maturely.

 

The age-old conundrum of smoke in pyrotechnics is one that is often over looked or avoided. For obvious reasons of bright colors, we try to fine tune compositions to emit 'less' smoke so our stars will not be obscured.

Creating smoke for the purpose of color or even smoke stars presents a unique challenge. Would I say this is beginner material? No- intermediate? eh, if you've got the patience for trial and error. AND the funds to get those expensive dyes that make up the color in smoke! So your difficultly curve is high, money is another issue (or not) and finally patience.

 

I've written a few articles on smoke generation and love smoke in pyrotechnics too. The main problems you will run into is flame development on the star's surfaces. As the star falls you must have a chemical incorporated to keep the air from fanning a full on burn. Same principle if you start a small fire and you blow on it to get it burning.

 

Now, I realize here that this might be old news to you and I apologize for the added fluff as it were- you asked about possible compositions...

 

Start with a standard white mix first: (since it is easy to make and you won't lose too much money if it fails)

 

Sulfur........... 16

KNO3........... 12

Charcoal...... 1

 

Now, even in a tube, if not rammed and choked, this composition will form a flame envelope and ruin the effect. The problem is compounded if it were a solid pellet falling through the air. But a solid pellet is what you are going for here; so that means you need to press your stars almost in the same way you might a comet. Since the composition is slow burning you don't want to make your stars larger than 1/2 inch- unless you are using large shells with plenty of altitude. Yes, the fire hazard will be great starting out but don't be tempted to shoot these over water as a work-around. If the star fails to ignite or burns and then goes out, you will need to 'try' to recover a star so you can figure out the issues. I.E. blew blind, (needs priming), burned and went out, (too much carbon build-up or oxidizer/fuel ratio wrong), no smoke but still burned, (flame developed and ruined the effect)...

 

You will be surprised at the lack of data out there for smoke stars, if you haven't already noticed. Those professional companies that fine tuned their stars aren't going to post the formulas for us to 'plink' with. And most homestead pyros out there just aren't that interested in it because of the time/resource/money consumption that goes into smoke. Everyone likes results and smoke is one that will quickly frustrate a pyro of any experience level.

 

A good yellow smoke:

 

Yellow Dye................. 5

KClO3......................... 1

NaCO3....................... 1

Powdered sugar...... 1

 

This was a development I did over a few months. Not all dyes like the same compositions. A red dye might do better with powdered sugar rather than charcoal or a green might burn faster or slower with flour over sulfur. Change one variable at a time and you should make progress!

The yellow above was not designed for stars but is a good place to start. It is fast burning in a rammed and choked tube and doesn't need priming to get started. Take some pictures of your stars and outline your methods here and I'm sure someone will be further willing to help you along. Good luck!

[Miech]

In my opinion a 1:1:2 mixture of potassium chlorate, lactose and dye is far superior to any sugar based smoke compositions. Such compositions burn way cooler than sugar basaed ones, and produce about the same amount of gas while burning. These compositions are much more suited for use in a stationary smoke bomb or for use under a parachute.

 

For a tutorial (or the like) about parachute shells, check out the 'Members Tutorials' section, I posted one somewhere there. It is far from complete but should give you a good starting point. I just have way too less time to write any test results I got so far in there...

 

For smoke stars, have a look at Shimizu's compositions. Most use unobtainable chemicals for smoke production, but they can be ajusted pretty well for use with modern dyes. This does not work with the ones using sulfur compounds, just with the ones using organic dyes. Some experimentation is needed though to give a satisfactory result. Also, some smoke stars are covered with gypsum and have a hole drilled in them, so look them up in the original publication, not in online databases.

[Dr Boom]

Uh Miech... you do know that lactose is a sugar, right?

 

Lactose : milk sugar

Fructose : fruit sugar

Sucrose : table sugar

Glucose : honey, fruits and vegetables

Maltose : barley sugar (aka beer sugar)

Xylose : wood or straw sugar

 

You do have a very good point about lactose having the coolest burn, or lowest caloric value.

[Mumbles]

I've attached a file from a Crackerjack seminar I think. It is probably the single most useful thing I've come across for modern smoke information.

 

The few smokes I've made always seemed to work best with a bit of carbonate added. It helps reduce flare ups a lot, and keeps the flame cool. There is a guy in my firework club that makes some nice parachute smoke flares. They frequently burn to the ground, but I've never seen one start a fire. They're kind of funny. He lifts and breaks them extremely hard, yet there this little purple smoke flare casually floating down. I wouldn't fire them in dry conditions though.

 

The dyes are luckily getting a little easier to come by.

 

There are two ways to do this. The first is to actually make them into stars, while the other is to make inserts. Shimizu has some good info about the inserts. The inserts don't require as much monkeying around with the formula. Let us know how it goes. This seems like a fun project. This year's Judges' challenge at PGI is to create a daylight display, so I'd imagine that it will be a hot topic.

Smokes the how and the why - Joseph A. Domanico - Crackerjacks.pdf

[scythe]

Hey mumbles, I don't suppose you have a version where the videos still work in it.

It would be interesting to see the actual colour of the mixes.

 

Also interesting to note is the percentage of accidents related to Smoke compositions, a whopping 66%.

And here I thought they were relatively safe (excluding the poisonous and carcinogenic types) pyrotechnic devices.

Edited June 5, 2010 by scythe

[Arthur]

I did see some youtube of smoke units in China, They were clearly perforated card tubes about 3/4 bore and 3" long with about 8 holes in the sides. This means that the comp can be ignited by a fuse train but while passing through the air, the smoke comp is still burning inside a tube so the airspeed doesn't affect the burn rate. The vid did show several smoke inserts still smoking when the reached the ground,-very messy.

 

Coloured smoke works usually by subliming an intense dye, white grey and black smokes sometimes are the combustion products of a slow mix well off stoichiometric balance.

 

Think MESS when working with dyes, those dyes get everywhere, they are also fine enough to float in the air in your workshop.

[Bearark]

Thanks for all the advice ! I just (as in 30-40 minutes ago) got my ball mill and have it running now to make some lift powder for my tests (I am so super excited you have no idea, well you probably do but YAY! ).

I think what I'm going to start with is a standard non parachute shell but instead of stars using these Smoke Crackers until I can get the smoke compositions down. I'll post my work as I go in this thread.

 

 

Thanks again for all your help !

[Mumbles]

I'm sorry, but that is the only one I have. If you want to get an idea what the smoke looks like, I think skyligher's site has some images.

[Bearark]

Just Thought I would Update on another item I found that would be related to this (And I think its amazing Idea). I found this http://www.wichitabu...ightshells.html during my intewebnet travels and it sounded like it may fit the bill (kinda)

 

I was wondering what yall thought about making smaller inserts to burst the line chalk in multiple places/colors instead of just one big burst (Though I will be making several that do have the one big burst as well )

 

I also found that hobby chemical supply has a red smoke mix that they say can be bound with NC lacquer and formed into stars, now only if I know what the actual composition of it was. (I guess I'll ask after making my first order with them)

Edited June 18, 2010 by Bearark