how are these rolled ministars made?

[klachner]

Hello,

 

i wondered how they make these round ministars which you can find as rocket or cake effects like on the attached picture.. if they are so tiny how do they get them started in the star roller? or is there a special method for these ministars? I only came across the screening "mouse turd stars" method, but this would result in little cube stars not these round rolled stars

 

 

[lloyd]

Klach,

Those are hardly "ministars". Those are large compared to many we make for low-altitude indoor mines! And please notice that they are NOT uniform in size. That wide a variation in size would never work in the professional close-prox industry.

 

We roll tiny stars "coreless". In order to do that, we start with a small mass of dry comp with a dry binder (usually dex) in the star roller. While it gently rolls, we 'spritz' the surface of the mass with coarse droplets of water from a spray bottle designed (or modified by poking out the nozzle hole) to make a very coarse spray.

 

After a few minutes of that, you get quite a number of 'micro' cores, about 0.020" in diameter. Those are screened-out from the fine powder, and allowed to dry. Then, they're used as the 'seeds' for rolling as-usual, but with FREQUENT screening for size. We can reliably get finished stars smaller than 0.060 (although we seldom make them smaller than about 0.090").

 

Lloyd

Edited January 15, 2017 by lloyd

[CrossOut]

Tho no where near as small stars as lloyds, ive used some granulated or riced bp for small star cores with great success. I usually do with roughly 2f granule size. Edited January 15, 2017 by CrossOut

[Zumber]

Use different mesh screens.

Prepare a batch of composition you need to do stars out of that obviously it must contains dry binder in it eg dextrin.

Damp that composition with water mix it well make a small ball out of it with your palms please note that it must not contain too much or too little water.

Get 20 mesh screen rub that ball over screen.let all your composition to pass through screen then collect that material add dry powder of same formula which you used for star.then roll it in your roller by adding dry composition and spraying water with atomizer spray.to get uniform stars use different mesh screen to separate and screen out stars which you are rolling in roller.

[klachner]

wow 0,020" thats impressive.. which star compositions would you recommend for this method or will all star comps work fine with this? and will it work in small batches too, my star roller is not that big

[lloyd]

I've tried it with - oh - fifteen or twenty comps across both BP-based and parlon/saran color comps with perchlorate as the oxidizer. ALL the ones we made commercially were bound by dextrin, although I've tried it with SGRS, too. It seems to work fine for everything I've tried, both ways.

 

LLoyd

[Boophoenix]

Klach, you want a small batch. Those tiny stars will grow up into a " holy cow " batch real fast and eat up a lot of comp. Think about it some people who use the lead shot cores start with a tea spoon.

[Mumbles]

I've done it as Lloyd describes. It's not hard. It just sort of takes a leap of faith in my experience. You can't just really spray once and let it tumble. You have to continually provide it droplets to seed the stars at the start. If you spray a few times and let it tumble, the "stars" can roll to the top and collect the fresh water faster than the underlying powder. It just takes a little getting used to. Worst case scenario, you can granulate it through a screen to about the core size you want, or make a batch of cut stars or something.

[lloyd]

What Mumbles said. I should have mentioned that thing about keeping up the droplets for a time.

 

Klach, one reason for doing it that way is that indoor 'theatrical' fireworks must produce as little debris as possible. Any amount of 'seed cores' on a stage where talent is moving about can cause safety/tripping hazards, and anything smouldering when it came down could cause a fire.

 

The other reason is that those indoor mines use such small stars that a large portion of their volume will be used-up if we employ an inert core. For the tiny volume given, we want 'pure pyrotechnic content' in order to give the best effect possible.

 

Lloyd

[thepyrotextbook]

These (very) micro-stars sound interesting. I think I might try this method out with some metallic color compositions, maybe some Veiline compositions. Thanks for posting this technique Lloyd!

[Tourbillon]

Started trying to hand roll some stars the other day. Started cores with a spray bottle and a large bowl. Bound with SGRS.

[lloyd]

Tourbillion,

You have obviously figured-out the method! Good job.

 

LLoyd

[klachner]

nice job tourbillion! what exact composition did you use?

[calebkessinger]

wow. Talk about picking it up quick!

[drtoivowillmann]

Dear Friend:

 

In industry they are made without any core in a so-called "granulation pan", Some people also call them "German-Star-Pan".

Their bottom is completely flat. The lateral wall of the pan is straight (90 degrees angle, no curve). They are completely open. So they look like a very large cooking pot.

 

Rotation velocity is at least twice of that of a common star pan.

The angle of axis is about 30 degrees (to horizontal).

In the upper side a fixed scraper goes inside, to losen composition sticked to the surface of the pan.

 

In the beginning almost all dry composition is put in.

During rotation water or solvent is rinsed onto it.

Readily small stars, beginning from about 1 mm diameter, are formed.

The grow up to 3 to 4 mm, if you want.

 

Using such a granulation pan, you have to learn again star rolling almost frim the beginning, because this processon practice, is quite

different.

 

Yours truly: Toivo

[Tourbillon]

nice job tourbillion! what exact composition did you use?

From F.A.S.T.

 

Colored flame compositions,

 

Low temperature class compositions,

 

"Red Star"

 

I played with the batch shown (no cores) and also made some using poppy seeds as cores. The biggest thing that helped was adding (15% I think) alcohol to the water untill they had become uniform in size.

Edited June 6, 2017 by Tourbillon