Rolling Stars

[justanotherpyro]

One thing that surprised me is how differently a star behaves in a shell compared to a stargun. I have some flitter to blue stars that when shot out of my star gun only 2/3 would light, and only 1/3 would successfully ignite the blue core. I stuck these in a 3" shell just so I could test the break of the shell (the PVC primer and glue method actually PyroJoe) and they all took fire and they all went to blue, despite it being a very hard break.

[Givat]

Does ant one got any experience using NC\acetone for rolling stars? (not cut or pumped)

Maybe some one used PCV\acetone to bind stars that where rolled?

[Mumbles]

I've never personally tried it but I did talk to people about it. About the only thing they said is use a weak solution of NC. I want to say around .5% or something. Otherwise it doesn't spray well. Also to be sure one has a good spray bottle.

[_Po_]

I don't like the amount of time it takes to dry stars and I don't want to make a drier. If I were to roll a tiny amount of composition onto already formed stars (1/4" for example) and went easy on the amount of high-alcohol (about 40%) solvent used, could I dry the stars in the sun without the risk of them being driven in? Cracking doesn't seem to be a problem, and with only a small amount of damp composition on the already dry-cored stars the problem would be further minimalized.

 

Has anyone tried or heard of this technique? It seems to make more sense than rolling a thicker layer on and then drying for a long period of time. If you're rolling more than one batch of stars at the same time, or evening out different sizes, it would be a much faster route of production, you'd assume.

 

 

At the moment my aim is 5kg of stars. So far I've got about 3kg of them rolled. I'm using an adapted composition by Bankley (couldn't find a name). I swapped the titanium (60 mesh) with aluminium.

 

BLANKLEY

 

66 - Potassium Nitrate

13 - Charcoal Airfloat

8 - 325 mesh Aluminium

8 - Sulfur

5 - Dextrin

 

They make a very bright white spray of sparks. When ignited on the ground the spray of sparks shoots up about a meter. They don't need a prime, they're easy to roll and they don't use too much of my precious aluminium powder.

 

I purposely tested their rolling capabilities. I overwet them, put too much composition on them, overwet them some more and again put too much comp on. The spiked slightly, but after a few more seconds of rolling they were round, smooth and without imperfections. (I use a nascar roller.)

 

So can anyone share anything about the tiny incremental addition/sun drying process?

[Von Bass`]

Okay, so i made another batch of tiger tail stars. 50g.

 

They were ball milled for one hour and then formed by hand into round/cylindrical stars.

 

I carefully dried them out on a piece of oak until they were solid enough to be moved. Then I put them in a container, a bit like a big film canister and put them in my oven.

 

3 days later i tested one just by trying to light it. It didnt.

 

I waited another 2 days, and still nothing. By this point I assume putting them all together in a container was a bad idea, and so have spread them out.

 

I also put them ontop of the oven, as I assume there will be more of an air current there.

 

Unfortunately I think the potassium nitrate has leached itself to the surface, as about 12 of them have a white coating.

 

Is there any hope for my poor stars?

Thanks for any help

[Pretty green flame]

Force drying stars is generally a bad idea, especially charcoal ones.By force drying them you may have driven them in and when you say the stars have a white crust on them this would mean that these stars are seriosly fuc***. I'd make another batch and leave them in a cool dry place for a couple of days. People on rec.pyro say charcoal stars may take a week or two to dry fully, ofcourse it all depends on the humidity in your area.

 

Be patient, i know it's hard but try it'll pay out

[Von Bass`]

alright Ill do that. Would it be worthgrinding up all the remainder and starting again from reforming?

[Pretty green flame]

alright Ill do that. Would it be worthgrinding up all the remainder and starting again from reforming?

Possibly as probably no chems got lost during drying. You'll have to try it.

[Von Bass`]

alright I'll do that. thanks for the help

[justanotherpyro]

I don't like the amount of time it takes to dry stars and I don't want to make a drier. If I were to roll a tiny amount of composition onto already formed stars (1/4" for example) and went easy on the amount of high-alcohol (about 40%) solvent used, could I dry the stars in the sun without the risk of them being driven in? Cracking doesn't seem to be a problem, and with only a small amount of damp composition on the already dry-cored stars the problem would be further minimalized.

 

Has anyone tried or heard of this technique? It seems to make more sense than rolling a thicker layer on and then drying for a long period of time. If you're rolling more than one batch of stars at the same time, or evening out different sizes, it would be a much faster route of production, you'd assume.

 

 

At the moment my aim is 5kg of stars. So far I've got about 3kg of them rolled. I'm using an adapted composition by Bankley (couldn't find a name). I swapped the titanium (60 mesh) with aluminium.

 

BLANKLEY

 

66 - Potassium Nitrate

13 - Charcoal Airfloat

8 - 325 mesh Aluminium

8 - Sulfur

5 - Dextrin

 

They make a very bright white spray of sparks. When ignited on the ground the spray of sparks shoots up about a meter. They don't need a prime, they're easy to roll and they don't use too much of my precious aluminium powder.

 

I purposely tested their rolling capabilities. I overwet them, put too much composition on them, overwet them some more and again put too much comp on. The spiked slightly, but after a few more seconds of rolling they were round, smooth and without imperfections. (I use a nascar roller.)

 

So can anyone share anything about the tiny incremental addition/sun drying process?

It is atually recommended to roll stars to about 1/4 inch, dry them for a few days, and then roll the next layer of comp on. For large stars ( larger than 1/2" ) it may be a good idea to dry for a few days after every 1/4 inch added.

[_Po_]

That doesn't really answer my question. I mean to roll about 1mm (that's 0.5mm each side) of composition on to already established stars. By established I mean 1/4" (that's 6.35mm) and properly dried. I guess what I'm asking is how fast 1mm of comp freshly rolled on a star will dry and whether the core will absorb much and become driven in.

 

...I don't think I'll get an anwser unless I experiment myself.

[bubbelpower]

Okey, i have two comments to that.

 

First one is, that the comp wont stick to the star unless you wet it enough, so the star will become wet again.

 

Second is, Why roll only 1mm of comp on a star? Its friggin unnoticable in the air.

 

 

 

 

And i also have a question: My stars always become very light. How do I make denser stars while rolling?

[_Po_]

I don't mean a single layer. The point of rolling a thin layer is to make the drying process very quick. A thin layer will dry much more quickly than a thick layer, so by rolling a thin layer, drying, rolling another very thin layer, drying, rolling another very thin layer, drying, rolling another very thin layer, drying (do you understand it yet?), it might take less time to complete the stars than the equivelant of the normal process of a thicker layer and drying for a few days.

 

Don't worry, I'll try it and see if it works.

[rocket]

Wouldn’t this make the star a bit weaker as in the layers may crumble, also this seems like a lot to time and effete just to try and dry stars faster. It may also take a lot longer than one would think considering the star has to be wetted again and again and allowed to dry.

[FrankRizzo]

No, this is standard practice. Unless you have a force-drying chamber, you should only build your stars up a maximum of 1/4" per rolling session.

[bubbelpower]

eyy, noone knows how to make dense stars? Ill better aks somewhere else then.

[al93535]

Hey Po,

 

On already dried stars when you add another layer the solvet does seep into the core. But this would actually help a driven in star! They outter dried layer will not let any more solvet evaporate. So when you re-wet the outside, you essentially re-enable the solvent to migrate to the surface again! but its best to dry in the shade. But if you do get a drived in batch, try re-wetting them a little bit!

 

But yes, drying the stars after adding so much thickness is a good idea. They dry faster, and it does help prevent driven in stars.

 

I rolled flash onto cores and let them dry. Then I rolled green comp onto those to 1/4" and let them dry. I continued with dark comp to 3/8", and last night another layer to 1/2".

 

My stars dry within 24 huors usually, but I am in the desert. 10-20% humidity at 90-105 degrees seems to dry stuff very well!

 

Here are pics of the 3/8" stars and 1/2" stars.

 

http://img.photobucket.com/albums/v242/al9...eeeightinch.jpg

 

http://img.photobucket.com/albums/v242/al9...nehalfstars.jpg

 

Yes by hand.

[Karlos]

Hallo. I ned youre help. I hawe a guestion for experts:

Which binders are using for round stars with metal powders as magnesium and magnalium in Japan and china. I know that veline stars contains dextrine, but dextrine is not suitable for stars comps. with much quantity of metal powders. In the Shimizu book is a reference, that NC lacquer is good for binding stars, but acetone is a stinking, and shellac cause poor ignition of colored compositions. Red gum is not to buy in my country. I was make good green stars with 25% magnalium and synthetic resin Rybetak, and this composition had good burning time and ignition, but rybetak is not suitable to milling. I jus try the some composition with shellac, and product hawe a poor ignition and long burning time....

Japanese fireworker making in preference stars with high burning temperature and brilliant ligt in last time. I thing that these comps. contains large volumes of matal powders and dextrin (SGRS) is not suitable....

Sorry my english is not good.

Bye.

[ewest]

Why do you say dextrin is not good for stars with a high content of metal in them? I've made Veline stars and they work really well. I use Denatured Alcohol and water to wet them when rolling.

 

And Dextrin is not the same thing as SGRS. I was unclear on whether you knew that or not. SGRS is Soluable Glutinous Rich Starch and is used mainly as the binder in Japanese fireworks. You can use SGRS in place of Dextrin but use about 2% less SGRS. For example if a comp calls for 4 parts Dextrin, use 2 parts SGRS.

 

And remember, no matter what type of star you're making you'll have to prime them before they'll ignite easily.

[pudidotdk]

You can use SGRS in place of Dextrin but use about 2% less SGRS. For example if a comp calls for 4 parts Dextrin, use 2 parts SGRS.

 

Parts and % is not the same

 

If it said 4% Dextrin = 2% SGRS it would be correct

[ewest]

Yes, that's what I meant, thanks for the correction.

 

Most comps are listed in parts that equal up to 100 so I just tend to interchange parts and percentages when I talk about them.

 

Comps that use Dextrin usually specify 4 parts Dextrin or +4 of Dextrin. What I meant to say is if you want to use SGRS just use 2 parts SGRS or +2 SGRS. I hope that clarifies it.

[Mumbles]

Totally unrelated to rolling stars but using a 1:1 ratio SGRS:Dextrin replacement makes some very hard stars. I know of some people who do this when they are going to be using very hard breaks for a huge spread, or in small shells where there is a lot of flash being used.

 

Also from what I have heard SGRS is a pain in the ass when rolling stars. It just makes a gummy mess. I've never actually tried rolling with it, and have very little rolling experience period.

[Karlos]

OK guys. My problem is not dextrine or SGRS. Making procedure with this povdered glues and water is no problemo. However my friend was maked stars with magnalium (cca 20%) and his grains had white small points on surface and he was used 30%alcohol, moreover grains produced warm.

Magnalium is too susceptible to oxidation as magnesium, bat not to much.

You can write, that composition with magnalium and binder as dextrine is OK, if is used 50%alcohol, but I want be sure, that my work is OK.

Shellac making stars relatively hard, but shellac is too mild retarder of burning and ignition.

Professionals from japan can use passive metal powders and glues with water, or speciall powdered resins in compositions. I dont know.

I add photos of my last round green stars with 25% magnalium on rape seeds.

In this composition was be used powdered resin(rybetak) for binding.

 

http://img02.picoodle.com/img/img02/7/2/21...nxm_083adf6.jpg

same stars with priming:

http://img01.picoodle.com/img/img01/7/2/21...edm_68bf566.jpg

 

effect(70mm round shell) black-white camera:

http://img01.picoodle.com/img/img01/7/2/21...mim_e811314.jpg

 

Ribetak is not so good, and I dont know which kind of binder using japanese pyro artists for classic brilliant various collored stars(peonyes).

 

Thanks for youre answers.

 

If anybody of you thing about possibilityes to contacts japanese(Chinese) pyrotechnisc or pyro-amaterurs, I will be happy.

 

Bye. (sory...my english is poor)

[Richtee]

Ball mill rolling-

 

I have had some success using damped pulverone/dex and a media-less jar. I mix the pulverone with a bit of water just to the clumping stage, trying to break up any large clumps, then the damp pulverone in the jar and add some fresh out of the mill BP with some coloring or metal content and let it roll for about a half hour.

 

Not consistant on size at all, I get from about a 1/16 inch to quarter inchers.. but pretty painless in work involved. Sort the stars with a screen for different sized shells.

 

On edit: I suppose you could hand roll semi-cosistant sizes and use that to put into the jar... Hmm had not thought of that. Just be sure to have them damp enough to pick up some dry powder and start to roll.

[Karlos]

I made many stars with synthetic resin as iditol, RIBETAK from US. I was trying make stars with red gum as binder et last weekend and no problemo. I used 6% of red gum in magnalium composition for red flame with strontium nitrate and 27% of magnalium. Why don´t you use red gum as binder guys? Dextrin is not optimal for metal dust composition, and red gum improve burning and ignition. I used rape seed as core, torro system and sieve for 8 mm balls. Red gum is good binder for cus stars and rolled stars containing magnalium. Perfect brilliant stars.

http://img14.imageshack.us/img14/2033/roundredmagnalium.jpg