most popular cut star size

[ST1DinOH]

just wondering what the two or three most common sizes of square cut stars are.

 

do some star types require larger stars (ie, a 6 inch shell containing a standard color comp vs a willow, would one be bigger?)

 

i'm thinking somewhere in the middle, i mainly build 3's and 6's so i was thinking 1/4 inch for threes, and 1/2 inch for sixes.

 

am i on the right track?

 

i assume these are the most popular sizes considering most people building larger shells would use round stars anyway.

[Pretty green flame]

For 3 inchers I use 10mm (~3/8") streamers (Silver, chrysanthemums...) and 6mm (~1/4") perchlorate colour stars. Don't make many 6" shells so I can't comment on those.

 

If you want to make cut stars, you should look into the loaf method, it let's you produce many sizes at once, whereas the "slab" method can only produce one size per batch.

[andyboy]

Trial and error, to many factors that influence the size although I usually make a No 1 White into 3 mm³ stars to use as cores in TT stars and Chrysantemum 6-8 and other fast burning but not so bright comps.

 

This is a slow burning comp especially with coarser Al, I tried making them 1 cm in the beginning but they fell all the way to the ground when shot in 3" shells and mines. They don't take fire easily so I figured they should be heavily primed, that takes away a bit of the size they can be made into as well. Off course you could make them into 1 cm stars but only if your shells are larger so they burn out before they hit the ground (hate it when that happens).

 

 

 

White star #1

Source: rec.pyrotechnics

Comments:

Preparation:

 

Potassium Nitrate.................................58

Aluminum..........................................40

Dextrin...........................................2

[qwezxc12]

If there is a 'standard' table, this is probably it:

Cut Star Size vs Shell Size

 

Shell Size...........Cut Color Stars...........Cut Tailed Stars

3".....................1/4" or smaller............1/4" – 3/8"

4".....................1/4" - 3/8".................3/8" – 1/2"

5".....................3/8" - 1/2"................1/2" – 5/8"

6".....................3/8" - 1/2"................1/2" – 5/8" or 3/4"

8".....................1/2" or larger.............5/8" or larger

 

Obviously, as everyone has mentioned, the relative burning speed of differing compositions needs to be accounted for; a 1/2" C6 or Chlorate color will burn much faster than a similar sized Ammonium Perchlorate color, higher % charcoal, or diadem star (like Slow Gold).

 

Rolled sizes vary by effect, but when using cut or pumped stars that need little or no priming, I almost always use 3/8" for 3in and 4in, and 1/2" for 6in ball shells. There are exceptions, of course - I made a 6in single petal Slow Gold brocade with cut 3/4" stars - I will lift it harder than normal, though and am hoping the stars burn almost to the ground.

[ST1DinOH]

thanks for the replies guys. i kinda figured depending on the star comp it would change the star size. and i'm sure you can use them as rising comets if you press them right.

 

looks like the most common cut sizes are between 1/4 and 1/2 with 3/8 being the clear winner.

 

any objections?

 

i see a few guys said 1 inch, must be making large shells.

[Mumbles]

3/8" is getting toward the small side of things in a 5" unless your stars are exceedingly slow. I have a blue star that I cut at 1/4", and would burn long enough for a 6". I don't make many 5" color shells oddly enough, but I'd probably use 1/2".

[tentacles]

Somehow it's telling me mumbles' post here is from today (Feb 19/09). Anyways, Just wanted to say, my 5" shells used 1/2" cut stars (I measured them as I cut slabs) of FSFOY. They probably could have been a bit bigger and with less prime (meal dust) but they worked pretty well.

[TheSidewinder]

Somehow it's telling me mumbles' post here is from today (Feb 19/09).

 

[Mumbles]

He's talking about how the post bumps everytime someone makes a new poll entry. Since I was the last poster, it puts me up in the general thread view screen with the time of the poll entry.

[TheSidewinder]

Ah, so that's it. Good catch. Thanks.

[Seymour]

For three inch round shells, I would make stars the size PrettyGreenFlames said, with a few mm range from those values.

 

(ie, a 6 inch shell containing a standard color comp vs a willow, would one be bigger?)

 

Perhaps not. Both have a wide range of possible burn speeds, which overlap.

 

 

Even if you have no plan to make larger shells, I often find myself making larger stars for starmines. 20mm would be quite normal for me in a three inch glitter, or most other streamers mine.

Edited February 27, 2009 by Seymour

[50AE]

I mostly use 1/4 stars, for colors and glitters, but 3/8 for charcoal fires. I'm speaking for 2" and 3" shells. Edited April 12, 2009 by 50AE

[firetech]

I seem to have trouble making cut stars..I might be making them too small, either that or I over wet the comp. What binders are you guys using?

[Mumbles]

If you don't tell us what kind of problems you're having, there's little we can do to help. Most any binders can be made to work for cut stars.

[psyco_1322]

90% of the time I use the binder that the formula calls for. What kind of 'problems" are you having? Cutting the stars small with not cause any problems.

[firetech]

I had a batch of my own formula 95/45/15/10 kno3/charcoal/sulfur/dextrin, which I have never had a problem with pumping, but when I tried cutting them they were hard to light and had trouble burning completely. There was a lot of reminance left over.

[psyco_1322]

Assuming that you remains were falling from the sky and not just burning on the ground. If you burn willow stars on the ground, most of the time you end up with a lump of glowing charcoal, this is normal.

 

I would say your stars are still wet. Pumping takes a lot less water to make the stars consolidate than does cutting. Even if you don't notice it, your using more water. This in turn means more (longer) drying times. Take on of your biggest cut stars and break it in two. They can appear to be well dried on the outside and still be wet on the inside. Usually if they are wet, a simple hard smash between two fingers will tell you. If you can't possibly crush it, its pretty much dry, but still check by splitting it in half. I use a pair of dikes outside, away from anything else to check stars. Try to scratch the center, if anything flakes off, its not drying, but if your leaving lines on a hard surface, they're done.

 

My last thought would be that you mixed your comp up wrong and it just simply won't burn well that way.

[Mumbles]

You can call it whatever you want, but the formula you posted is a rounded off version of a formula Mike Swisher posted on the internet several times. It's also a close approximation to a famous spider star formulation with a little extra charcoal. Both of said formulas are designed to be cut.

 

Like psyco said, make sure they're dry. Give them at least a few weeks. These formulas are designed to be ball milled as well. It sounds to me like they're not dry yet, or you over wet them. If you over wet them, there might be some white crystals on the exterior.

[Mario1]

Id have to say 1.

[dagabu]

You can call it whatever you want, but the formula you posted is a rounded off version of a formula Mike Swisher posted on the internet several times. It's also a close approximation to a famous spider star formulation with a little extra charcoal. Both of said formulas are designed to be cut.

 

Like psyco said, make sure they're dry. Give them at least a few weeks. These formulas are designed to be ball milled as well. It sounds to me like they're not dry yet, or you over wet them. If you over wet them, there might be some white crystals on the exterior.

 

A few weeks?!?

 

I have a batch that I made a month ago and they are still drying. I complained and complained about these stars not working, the exactly same issue Psycho had. They are OK but still have weeks to go till they are ready to use in a big shell.

 

I was told that this comp should be made in the winter months so there is a long drying time before shooting. I have little square black sugar cubes that look a lot like the Borg ship after burning.

 

D

[50AE]

1/4 stars, they work with almost everything

[Karlos]

Size of cut stars is not so important as size of final round star. Cut star is only core for round star. Most of cut stars are coated to round stars with the same composition. Relation between size of final stars and shell size is more important. Edited December 16, 2009 by Karlos

[firetech]

Who voted 1"?

[Mumbles]

Karlos, cut stars are the traditional type for all canister shells. It allows you to pack the stars into the shells much better, and really lock the stars together. Round stars are like a sack of marbles, there is no way to pack and lock them in as well as cut or pumped to an extent. Commercially many canister shell manufacturers have moved to round and pumped stars primarily for economic reasons, but that doesn't mean cut stars are only used as cores. In fact, the only place I know that does that is traditional japanese shells. It's much easier to star straight from cores and roll the entire time.

[Karlos]

Canister? Oh..sorry, surely. I thinking only about asiatic balls.