Help with a granite star formula.

[DeepOvertone]

I recently made some large stars using the formula from the skylighter website.

 

KN03 22%

Zinc 62%

Charcoal 11%

Sulfur 4%

Dextrin 2%

 

prepared as described and was going to make cut stars and decided to try out my new 7/8" pump. I first decided to try the loose mix to see how it burned. I was surprised that when I tried it ignite it with a fuse it actually seemed hard to ignite. it took a few seconds for the pile to start then burned with lots of smoke and blue/green flame. I then damped with water and pumped up a few stars. I will say that they may have been a tad wet because when I was pressing on the pump i was able to get a drop or two of water out of them. So I was hoping that I didnt leach out too much kno3. I let them dry for about a week before priming with bp with a bit of mg to aid in ignition. I let that dry overnight and went out to try one. The prime burned fast and furious but the star just sat there and then finally took fire. It seemed to burn and not comsume it self. I was left with a star shaped block of blue green ash that was just half heartedly burning. i touched it with a stick and it crumbled pretty easily. Dissapointed, i tried one out of a 1" mortar. Again the prime went great but the star didnt light till apogee and burned all the way to the ground then hit with a thud/big poof of smoke. I went check it out. again same blue/green pile of ash that burned for a min or so. One thought. I wasnt using zinc DUST. Im using some stuff i got a while back from discount pyro. More of a granulated consistency. Any ideas? Is this just the way these burn? I've made other zinc formulas with perc and they are quite energetic. So I was hoping for something a bit more than a smoldering pile of trash.

[hst45]

Well, for what it's worth here's the formula I use for Granite stars

 

80 Zinc

28 KNO3

14 Charcoal

5 Sulfur

2 Dextrin

 

 

Yeah, I know, it add us to something other than 100, but it's a ratio, not a receipe to yield 100 gms. I do these as cut stars, prime them with a good layer of tigertail and they light great and burn with an aqua colored flame and a sparky orange tail. This is with zinc dust, although I don't know the mesh off-hand, but it's pretty fine.

 

Hope this helps.

[DeepOvertone]

Thanks,

 

I have a bunch of zinc dust on the way in and I'll try these again when that comes in. Do your stars leave a pile of unburnt crud or do they consume themselves?

[hst45]

If I burn a cut-star on a plate, for example, it does leave a blockish residue, rather than consuming itself like a BP based star would, for instance.

[DeepOvertone]

OK, I decided to use the rest of my good zinc dust to try again. This burned much better so it must have been the size of the zinc(much less leftover also). I'm going to make some cut stars out of it and see how they do.

[justanotherpyro]

I have the zinc from discount pyro as well. When I tried using it years ago I had the exact same problems that you described because of the mesh size. It does however have a use. You can react it with CuSO4-5H2O to yield Cu powder which I think I saw somewhere on this forum for a use in a blue comp.

 

EDIT. An idea just came to mind. You can get pure copper powder using the above method, then you can recover the Zinc with powdered Iron ( I picked mine up years ago in a coffee can from a machine shop). You can also do an Fe/CUSO4-5H2O reaction. With the Iron you can safely extract the pure Zn or Cu metal if you filter while using a magnet.

[flamingape]

H2SO4+Cu+H2O2-------->CuSO4

unbalenced but it works

 

I have a few large jars of ir right now... Ive been working for the past few days making it. You get pure product in a few hours

[DeepOvertone]

Thanks for the info. I made a couple dozen 3/8" stars and some 7/8" comets/stars and im gonna wait for them to dry and I'll see what happens. So thanks for the ideas regarding the extraction. All of that seems like allot of trouble when I can pretty much buy anything I need, so I'll maybe just mix that junk zinc with some sulfur and burn it up. Dont have too much of it anyway probably about 3/4 lb. These are my first posts here and I definitely appreciate the help so far. I hope to build a good relationship with all the pyros here.

[flamingape]

im sorry but 7$ for a liter of H2SO4 and 3$ for a few large bottles of peroxide and freemetal (think pennies, use pre 1982) and you have liters of copper sulfate

 

heat up post 1982 pennies in a torch to melt the zinc out (as well as making copper(II) oxide), it only takes a few seconds on a propane torch. and you have zinc sulfate

 

as for the iron... its so cheap its actually cheaper for people to throw it away than recycle it (unless you are in for some home chemistry)

 

stars would be a better use than unconfined burning of good (cheap) material, without neglecting safety you should cut all monetary corners necessary because this is an expensive hobby

 

 

mix the hydrate with powdered Mg (actually dont its dangerous as hell) and you have a flash type mixture. Im too afraid to get the anhydrous near any metal after I tried what I saw on this

 

3 grams made a bang like a gunshot, it's shock and pressure sensitive as well, It got unbearably hot to the touch after I softly pressed it in a tube.

[Mumbles]

I don't know where the talk about dissolving copper came about. Iron will certainly not reclaim zinc from solution though.

 

Also, that youtube video in the latest post has nothing at all to do with anything.

 

Thirdly, quit talking about flash, it is entirely off topic, and is being done in a relatively unintelligent manner.

[DeepOvertone]

I want to thank everyone for their help and input!! Tonight I tried those stars and comets I made with the good zinc. They worked beautifully and I was actually quite impressed with the effect. I was firing them from 1" mortars. I made a couple mines and fired a couple of the comets. Next I'll be making some 4" round shells with these stars. I'll be posting this in the competition section sometime around july. Untill then... Thanks.

[sparksnsky]

I hope I'm not out of topic with this.

 

I' was ready to make some granite stars using the above mentioned formulas.

Before proceeding to mixing things I always study. So I read that Zn tends to decompose in water and much more in alkalies. So I was wondering how safe are granite formulas and if the addition of boric acid can prevent the reaction.

Is anybody aware of this?

Thanks

Edited July 4, 2009 by sparksnsky

[Weasel]

I hope I'm not out of topic with this.

 

I' was ready to make some granite stars using the above mentioned formulas.

Before proceeding to mixing things I always study. So I read that Zn tends to decompose in water and much more in alkalies. So I was wondering how safe are granite formulas and if the addition of boric acid can prevent the reaction.

Is anybody aware of this?

Thanks

 

 

If you add a pinch of boric acid it will be fine. I haven't made any yet, but i'm looking forward to making them next year. My pyro season is over for this year . fired em all last night for the third so i can watch my towns show today.

[Seymour]

Some heat will be generated, but unless you leave a large mass of damp composition it is unlikely to heat to dangerous levels. Once stars are made and they are spread out to dry the danger is minimal.

[DeepOvertone]

I'm very surprised to see this thread being posted on again!! I've never had any heat issues or any type of foaming or anything from these mixes. Seem pretty safe. Try to use only as much water as you need. I find that they work well as pumped stars so it doesnt take much water to pump anyway. Good luck!