microstars

[MadMat]

Anyone know where I can find info about making micro stars? I am about to try my hand at making time rain for the first time. I made up some N/C lacquer by adding approximately 140 ml acetone to 14 grams of double base smokeless powder. It seems very thick (needs a bit of thinning with more acetone?). Am I right in assuming that the micro-stars need to be completely encased in the matrix star material? Do the micro-stars actually need to be primed? ect. ect. I tried looking for some informational literature, but so far have been unsuccessful.

 

[greenlight]

This is all I know of at the moment:

 

http://pyrosource.wikia.com/wiki/Crackling_Micro-stars

 

Theres also a skylighter article on bismuth subcarbonate dragon eggs I think.

Don't know if this is of any help but I have made them before from bismuth trioxide and when I mixed up the nitrocellulose lacquer it was quite thick and poured very slowly.

I made the mistake of making them too big (3mm x 3mm) when i cut the rubbery mass. These just exploded with a loud report and no real crackle. I reworked the mix with fresh NC and made very small grains this time and they worked extremely well in 3 mines that I used them in and i just used BP as the prime. Haven't put them in a shell yet though.

[OldMarine]

Here's Ned Gorski's video on crackling microstars using Lloyd's formula. These work great:

 

The NC lacquer mixture is critical.

Edited October 28, 2016 by OldMarine

[MadMat]

Thanks for the info guys! this is something I've wanted to try for a while now, but haven't got to yet.

[OldMarine]

Thanks for the info guys! this is something I've wanted to try for a while now, but haven't got to yet.

I'd PM Lloyd about the formula. It is very easy but also easy to screw up.

[MadMat]

Well, I tried a small experimental batch (50 grams). I ran them through a 10 mesh screen. The micro-stars came out a little smaller than I would have liked, but test firing a few of the grains produced a very good visual with a gentle a gentle crackling sound. All in all, not bad! Now, I just need to make up a matrix comp, get some stars made and try out a small (1-1/2") shell.

Edited October 28, 2016 by MadMat

[OldMarine]

I save my smaller granules for the brocade effect which is basically what the time rain is. I don't prime the crackle until i've sized it and then only prime the larger ones. Smaller grains used in a matrix don't need prime and those unprimed smaller grains can always be re-wetted with acetone and be cut into larger stars if desired.

 

I'm waiting on some 1/2" Winokur 39J stars with crackle granules to dry as we speak (type) and can't wait!

[Seymour]

In my experience the NC can be very important, but so is MgAl particle size. Coarser means larger and louder, but fewer explosions. Finer MgAl means many more smaller pops.

 

Note that it is possible to make good dragon eggs with no Nitrocellulose, although I do almost alway use it.

With Bismuth trioxide I've had great success using the formula 37.5% Bismuth trioxide, 37.5% CuO and 25% MgAl, + Nitrocellulose (I have varied the quantity, but I usually aim for 4% binder). This formula was created by David Trimmel.

 

Search Dragon eggs, Dragon Flowers and Crackling Microstars in this forum search function and I guarantee you will find dozens of threads discussing various aspects of their manufacture in detail.

 

In case anyone here has some confusion over the terminology, Dragon eggs and Crackling microstars are the same thing. They are the bit that either goes bang once, or many times. They can be primed and used as is, or embedded in a matrix to create crackling comets or stars. They can be used as cores for any stars, colour, glitter, other streamer, whatever. I have rolled a layer of composition (small crackling microstars mixed with a matrix) in colour changing stars so that they burn one colour, then crackle and then burn a different colour. You can do many many things with these.

 

 

Dragon Flowers are a smoldering mix that is coated over a dragon egg that explodes only once (for best results). The smoldering mix usually contains Titanium so when the core explodes it scatters a shower of sparks. Dragon flowers can create a lot of effect from a small volume and are very common in consumer and professional fireworks.

 

Here are a few links to get started, but it is only a small sample just from this one website. There is a lot more info on this website (and others)

 

http://www.amateurpyro.com/forums/topic/7432-dragons-eggs-in-consumer-shells/?hl=%2Bdragon+%2Bflowers&do=findComment&comment=97464

 

http://www.amateurpyro.com/forums/topic/10663-bismuth-or-red-lead-i-need-your-opinion/?hl=%2Bdragon+%2Bflowers&do=findComment&comment=141877

 

http://www.amateurpyro.com/forums/topic/8891-dragon-eggs-recipe/?hl=%2Bdragon+%2Bflowers&do=findComment&comment=116314

 

http://www.amateurpyro.com/forums/topic/8857-rolled-dragon-eggs/?hl=%2Bdragon+%2Bflowers&do=findComment&comment=115885

 

http://www.amateurpyro.com/forums/topic/7796-an-easy-way-to-make-dragon-flowers/?hl=%2Bdragon+%2Bflowers

 

http://www.amateurpyro.com/forums/topic/5072-dragon-eggs-dragon-flowers/page-3?hl=%20dragon%20%20flowers

 

http://www.amateurpyro.com/forums/topic/6209-usapyros-no-nc-dragon-eggs/page-2?hl=+dragon%20+flowers

 

Finally, in case there is any confusion, the term "microstars" does not mean "crackling microstars". You can make microstars with any effect. Slower burning colours, streamers and so on are often preferred, but your creativity is the only limit.

 

Happy crackling!

Edited October 29, 2016 by Seymour

[OldMarine]

Like Seymour said, any star comp can be a microstar, I use the scrap from parlon cut rubber stars for matrix comets (1") in my little fan cakes.

[pyrokid]

Can you share some details about your matrix comet process OldMarine? What composition?

[OldMarine]

I like using charcoal comps for the matrix comets. I just test fired a Winokur 39 J with 20% crackle -20 granules and they were spectacular. More of a sizzle than a crackle.

These aren't really as dry as I'd like and unfortunately the vegetation is too dry for a rocket launch so the stargun is my only test choice.

[Mumbles]

The matrix formula in Hardt is basically C6 with a few parts coarse flake Al. It's used 80 parts matrix to 20 parts crackle granules. It should be noted that I like to make sure there is a tail the crackle is going off inside of. It kind of looks out of place without it. On a personal note, I like a longer tailed comet for these things. A personal favorite of mine is this formula I call Soft Silver:

 

Potassium Nitrate - 50

Sulfur - 15

Charcoal Airfloat - 10

Charcoal, 80 mesh - 10

Aluminum, flitters, (Eckhart 41813 usually) - 10

Dextrin - 5

Gorgeous tail on it's own, and really pops with some crackle. I really like the idea of the glitter too though. I bet those stars are going to be awesome.

Crackle matrix comets are also sort of cool to use in married comets. Have the base matrix comp in the bottom pellet, and the matrix with the crackle in the top pellet. It's kind of a neat and startling effect when a tailed comet, especially ones with flashes, starts sizzling and crackling at the end.

[Arthur]

As the time rain bits are small (very small!) they are very sensitive to ingredient particle sizes, some batches will work better than others simply due to the way that the ingredient size mix settles out in the bottle.

 

Start with the NC rather wet! it dries rapidly. Mix it wet, perhaps in a snap top bag, then let it dry granulating it as it passes through it's optimum viscosity.

[MadMat]

I used C6 with 7% titanium added for my matrix. Doing a test burn of a single star looked fantastic! It was amazing how many sparks and gentle pops came out of a single 1/4" star. Was hoping to post a video of the star burn, but having tech issues. Made a shell just in time for the weather to go to crap here. I've got high hopes for this shell, but it looks like I'm going to have to wait a little while before launching it. If Arthur is right about different batches performing better or worse, I'm hoping this small batch isn't simply beginners' luck!

A few notes about making the microstars. I made my N/C lacquer rather thick...the first time around. I didn't care much for my granulation, so I crushed up the microstars and added more N/C lacquer, this time thinned quite a bit with more acetone and reformed them. This might be noteworthy in the production of time rain microstars, since, contrary to what I have read, they seem to ignite rather easily.

Edited November 3, 2016 by MadMat

[FlaMtnBkr]

Dragon eggs or crackle need to be made so that each piece makes one loud bang. You don't want one piece to make multiple small pops that give a crackling sound despite the name crackle. For one thing much of the micro star goes to waste as small pieces light but usually the bulk of it is thrown off and goes to waste unreacted. This may not be the case as much in a matrix star or comet but is the case in individual stars.

 

Also, the light crackling sounds ok up close but will be barely audible up in the sky at a distance. When you see the big shells go off that fill the sky with sparks and flashes and all light and crash at very close to the same time and give the crackling roar, each dragon egg is exploding once and is impressively loud about like a 1 1/2" 'Black Cat' firecracker or louder like a .22lr for the better made stuff. This is the only way it is heard at a decent volume hundreds of feet in the sky.

 

Well made dragon eggs should be 2-3 mm (or about 1/8") cubes before priming and should all explode at once in a very impressive explosion for the size. As above, it should sound like a standard firecracker or .22 up close. When testing an unprimed one with a torch they will often make my closest ear ring for a moment and I've even had them knock a splinter lose on a soft board and take a small chunk of concrete off if lit on the edge of a rough finished concrete slab.

 

Many times DE will have to be tuned to get them to work correctly and anytime you get a new batch of chemicals unless you just get lucky. This is mainly accomplished by altering the MgAl particle size. If a piece of the desired size makes many small pops with much being unreacted once a flame is removed, the MgAl is too fine. On the other hand, if the piece glows red and then cools off without a pop or the glow phase is really long (2-3+ seconds) before popping then the MgAl is too coarse. If the bismuth trioxide is to coarse it can also cause this though this shouldn't be an issue if it comes from a pyro supplier.

 

If a piece makes just 2-3 pops and consumes most of it, it's possible to make smaller size pieces and have them pop all at once but this doesn't always work or might not work well for your intended use.

 

And if you made your pieces on the small side and they glow and go out, it's possible to make bigger pieces so they create and retain enough heat to work correctly. I've taken some like this and made really big 1/4" cubes and had them go off in one impressive explosion. Though it's not 8 times louder and is a waste of composition.

 

If your eggs do either of the above scenarios, the first thing to try is use the next available size in the direction you need to go. I've had good luck with the commercially available MgAl that is labeled 200 mesh. Though it seems like there is usually quite a bit of fines and the actual size probably depends on if it came from the top or bottom of the barrel. If using the stuff available from August you may need the next bigger mesh (smaller particle size) since his is accurately sized and won't include the fines. If the next available size seems to go too far in the other direction then you will need to mix sizes. You will just have to guess on the mixture based on how it's behaving and using common sense. You also need to try them in a device in the air because this can cause them to cool off a bit and slightly change their behavior.

 

If not using them in a matrix star you need to make sure they have a good hot prime. Preferably one that burns slow and contains a metal or silicon that burns into the surface and lights the piece over the entire surface. This helps ensure it's lit evenly and that it all explodes at once instead of one part getting hot and exploding before the rest. The even layer of prime also helps to keep it from cooling while traveling thru the air.

 

Another seemingly important step is making sure you get plenty of NC into the mix. This can be done by using a 10% NC lacquer and adding an excess so the mix is too wet and almost soupy which makes it easier to get an intimate mixture and even distribution of chemicals as well as getting more NC in. Keep stirring occasionally and scraping the more dry pieces on the sides down into the wet mass until is a dough like consistency that can be worked with without sticking to everything. Using straight acetone in the lacquer will result in a very quick drying mix which will require working quickly and smaller batch sizes.

 

I believe it's possible to add a small amount (10% or less?) of pure alcohol to your acetone which will slow down how quickly it evaporates and give a more reasonable working time. I think if you add too much it begins to separate and form a boundary layer but not positive. I think it was Lloyd that has mentioned this on one of the forums? I tried it once a long time ago and it seems like it did help but I don't remember exactly and didn't experiment enough.

 

I have tried a bunch of formulas but the 37.5/37.5/25 one seemed to work the best for me. I've also had really good luck using double base smokeless powder and I usually use Bullseye brand. There are some low bismuth content formulas I still want to try and some have expressed wanting to use a binder other than NC. I think in these cases a small addition of oxidizer such as KClO4 would be beneficial and help the smolder phase like the NC helps with. I've been meaning to experiment with this but thought I would mention it in case NC is hard to get for anyone or they don't want to work with acetone.

 

Sorry for the long post but hopefully someone finds it helpful.

[maddy]

crackling star compositions...

[Yus]

I used rolled 1.5...2.0 mm microstars for crackling flower and stirred 1.5 mm for time rain (comets). Base for comets: KNO3 - 60, C - 30, S - 10. Dextrine - binder. Add 3% over Rosin for slow burn and BaCO3 to make heavier star. 20% Ti or FeTi add to slow and hot prime to obtain crackling flower effect. Best and loud crackle composition: CuO - 40, Bi2O3 - 30, AlMg - 30.

 

0:11 - crackling comets.

0:18 - crackling flower.

 

https://youtu.be/2Gm-lk7BQKo

[Nitrotitanite]

Really nice effect, I also did microstar this year but it did not go well only small poff and some rare crackling I think depends on the too small 320mesh mgal, I will try again but find 200mesh mgal hard.

[rellim]

There is a table of stoichiometric tests in DragonEggStudy.pdf. I think I got this from pyrobin.

I get good results from row 4 substituting bismuth trioxide at a .903 oxygen stoichiometric ratio. I chose row four for its short delay and loudness.

[Yus]

Base: KNO3 - 50%, C - 38%, S - 12%.

Microstars #1: Ba(NO3)2 - 65%, AlMg - 25%, Bi2O3 - 4%, S - 3%, Red Gum - 3%.

Microstars #2: Ba(NO3)2 - 40%, S - 20%, AlMg - 40%, Red Gum - 3%.

Microstars #3: CuO - 65%, Ba(NO3)2 - 10%, AlMg - 25%, Red Gum - 3%.

Powder AlMg: d < 0.04 mm.

 

https://youtu.be/dlkMKhfW2SY