Swimming stars?

[MondoMage]

Do anyone have any links or references that discuss how the "swimming" effect for stars is achieved? I'm not talking go-getters or anything like that - I've generally seen it in ball shells, and the effect comes near the end of a star's burn time. They're dropping through the sky in the expected pattern and suddenly the stars take off in random directions (like a go-getter, but not quite).

 

One rumor I read was that the star cores were rolled in clay (or other inert material) and a tiny section was filed off to expose the core, then the whole thing rolled to a larger size. I guess that would work, but seems kinda labor intensive.

[memo]

i have heard and not done it myself that you can use a crosette or cavity star, paste a you would a regular one. use no break or anything inside the cavity and it will swim at the end of the burn

[Mumbles]

I've heard what you described as well. I agree it seems quite labor intensive, and probably a bit dangerous. There are some other potential solutions. The core formula basically has to be a violent burner though.

 

Some high metal fueled stars burn quite violently. They can fly around if only lit on one side. One potential idea I've heard is to paint cores on one side with a hot prime and roll them up in a relatively cool burning formula. Low metal or organic colors, charcoal streamers, etc. would potentially work. The idea being that once the star burns down to the core, only the primed side will light and the star will propel off in a direction.

 

Otherwise they can made like Memo described. You can make very small stars in this way and use them as cores. This is still a relatively labor intensive method though. Each core has to have the cavity covered, and then the star needs to be inhibited in some way. This is probably most efficiently done with a sprayed on material to prevent it from burning.

 

Along these same lines, I've often wondered about making hollow cylindrical stars. A pellet with a hole through the center essentially. Use these as a core for rolled stars. When they light, the hollow portion will ideally jet them around. It's not perfect, but far less labor intensive. Along these same lines, rolling a fast burning star comp around blackmatch and cutting them up may also work. The BM should burn faster than the star, and make the core. This is essentially how the original go-getters were made.

[OldMarine]

Are the stars in this video fish or go-getters? The last one is awesome.

 

[Maserface]

There is a little bit of information in FAST about swimming stars, Shimizu describes the use of a fast burning composition, that is cut into small cubes which are used as cores of rolled stars. A corner of the cube lights first and propels the star.

[CrossOut]

I have been searching for that star comp for a long time... I do know the effect is produced by the composition its self and not a specific shape. So whether the star will take off near the end of its burn is somewhat random but reliable results can be achieved. Ive scoured several fireworks articles and forums but have yet to find a working formula. Or anyone willing to divulge said information for that matter. I have reason to believe it is a AP composition but.. no one is willing to talk

 

If you do find anything please let us know!

Edited November 23, 2016 by CrossOut

[pyrojig]

What I have read and seen is usually accomplished by ap composite ( colored rocket fuel for lack of better description ). Usually pressed into tubes

[pyrojig]

http://www.pyrobin.com/files/DIY%20Go_Getter%20tool.pdf

 

Here is a simple means to make go getters

[Ubehage]

Do anyone have any links or references that discuss how the "swimming" effect for stars is achieved? I'm not talking go-getters or anything like that - I've generally seen it in ball shells, and the effect comes near the end of a star's burn time. They're dropping through the sky in the expected pattern and suddenly the stars take off in random directions (like a go-getter, but not quite).

 

One rumor I read was that the star cores were rolled in clay (or other inert material) and a tiny section was filed off to expose the core, then the whole thing rolled to a larger size. I guess that would work, but seems kinda labor intensive.

I would guess that they're made the same way as go-getters, but in "reverse". Something like what memo talks about; a crossette without the cracking.

[FlaMtnBkr]

I think some comps just tend to swim when they are lit in one spot. They are likely the more fierce burning comps and ones that produce lots of gases. I can't think of what off hand but there have been stars I've made that when lit on the ground with a torch, would burn a second and then scoot off thru the air.

 

I imagine if you coat your stars with something to inhibit flame or only prime one side of a cut star you may have better luck. If you break up plexiglass into small pieces and add to acetone it will dissolve in a few days into a thick lacquer. I would also add some airfloat charcoal and I bet you have a fairly good, cheap fire proofing 'paint'.

 

I also wonder what would happen if you stuck a 1/2" or so piece of thick visco into a star? Some of the thicker 1/8" stuff has a bunch of thrust and if you light and toss a piece in the air will fly all around and go 30+ feet away. Would be a pain but might get something moving you like and maybe just add a few sparks?

 

Just some thoughts.

[pyrokid]

I always thought the effect was produced by coating a cubic (cut) star made of a fast burning composition in a slower burning composition. The corner of the fast burning composition ignites first and propels the star. I've never been able to produce the effect properly. The more I think about it, the less ideal it really seems. The thrusts from the eight corners would in principle cancel each other out.

 

The clay coating method is a new one for me and it has the sound of a Japanese technique. If star size was consistent enough, a tray-holder could be fashioned to facilitate the large scale grinding of stars. I'm not sure what the ignition hazard would be. This method has the advantage of ensuring that star ignition occurs only at one point. I would appreciate hearing more about this technique if anyone knows anything. I am curious how the clay is made to adhere to the star.

 

I've seen large Japanese shells that accomplish the effect with a multitude of compositions that ignite many seconds into the star burn duration. The coolest effect is when the jetting stars are layered with dark composition.

[TYRONEEZEKIEL]

 

One rumor I read was that the star cores were rolled in clay (or other inert material) and a tiny section was filed off to expose the core, then the whole thing rolled to a larger size. I guess that would work, but seems kinda labor intensive.

 

This is exactly the way this was done in the old days, and is not too labor intensive. My fireworks mentor shared with me that when he worked in the factory they would roll a layer of calcium carbonate (chalk) on the stars. Then touch each star on a belt sander to expose a small area of comp. Then they would roll em all in prime. They called these zippers or zingers. I can't remember which, but the produced the exact effect you desire.

[OldMarine]

I watched a video someone posted of that process but rather than prime they rolled another comp on so as to have a petal that suddenly changed colors and zipped away. I'm pretty sure I bookmarked the thread or favorited the video so I'll track it down. It was back when I first started the hobby so I watched in wide eyed fascination. Didn't hit me until Tyrone's post that it was what I'd seen.

[Wiley]

I like the white pearl in the Spanish pdf, but binding with water in the winter is tough, so I "invented" a silver streamer formula that would be similar, but bound with acetone.

 

Occasionally, if the surface of the patty is not completely homogeneous and begins to skin, cracks can form as the knife passes through the skin and slightly deform the patty. I pick these cracked stars out because I noticed that if the crack is deep enough, the stars fly erratically. It doesn't seem to matter what side is lit first, but I haven't seen what they do when fully primed. That may well change their behavior.

 

EX Silver Streamer

 

KClO4 -------------------- 0.530

Red Gum ---------------- 0.060

Parlon -------------------- 0.110

MgAl ---------------------- 0.140

Al (60 mesh, eBay) --- 0.160

Edited November 27, 2016 by Wiley

[Mortartube]

Wiley, do you think that you could deliberately crack the stars after they have been cut with something like the point of a tooth pick or bamboo skewer?

[memo]

I tried to make some swimming stars for a six inch can shell, I rolled a layer of clay , dried it then sanded a spot and rolled it in more comp. it came out ok.

 

[Arthur]

I suspect that there is a method like a pill box star (simply pressed into a tube). If the tube burns a colour comp first then has a faster propellant comp the effect would be a standard star that swam part way through it's burn.

[memo]

they are rolled stars .fast comp rolled to 1/2 inch then a layer of clay. sanded the clay left a flat spot, rolled again to almost 1 inch with c6 then primed

Edited January 4, 2017 by memo

[NeighborJ]

Memo have you burned one on the ground and recovered the shell? I'm curious how much the hole eroded and if the entire clay shell stayed intact.

[memo]

I have not closely studied the shell, at a quick glance it looks like a portion of the shell has burned away. there is still over 3/4 of the shell left. I just sanded the star until the comp showed

[NeighborJ]

I was just curious. I am considering trying this with a strobe formula so it could have multiple jets from each star but it would likely explode if there was too much confeinment.

[memo]

if you want it to swim i think only one jet would work you can control some what the size of the jet by the depth of the sanded hole, then again you can try it on a couple of stars shot from a star gun

[pyrokid]

Memo, can you please offer some more details about your method? In particular, I am curious about:

 

1) What type of clay? I am assuming fine bentonite. Did you add any binder?

2) What type of sanding apparatus did you use?

3) Did you paste some priming composition over the exposed star composition to bring the star back toward round and ensure ignition?

4) Can you imagine that the thickness of the clay layer influences star jetting characteristics?

 

 

Thank you!

[memo]

the cores were charcoal streamer with 20% ti rolled to 1/2 inch they were primed, then used kitty liter ground fine in a coffee blade mill 200 grams of clay 6 grams of dextin rolled that onto 1 kilo of stars. I didn't think it was a good enough layer so I added a bit more. dried it in the hot box. then I used a belt sander to sand into the comp with about a 1/4 inch circle showed. then rolled C 6 to just short of 1 inch primed and dried again.

[NeighborJ]

Oh Memo, I knew I should have worded that better. I want to have multiple, consecutive jets shoot out of the same orifice by using a strobe formula. Imagine it-one star with multiple direction changes. It would look like you had three times as many swimmers in the sky.