Will this charcoal still work for these stars?

[Bransen111]

Hey everyone! so i made my first bottle rocket last night and it worked way better than i ever expected so thanks for the help, now I'm ready to add a small star to the top of it and i was planning on using this star composition, being that most of the stuff it needs i already have.

 

Firefly #3
Source: PML Digest 391, post by L.Niksch <LNiksch@aol.com. This formula is provided with the "firefly aluminum" from Skylighter.
Comments:
Preparation: Ball mill potassium nitrate, Air Float charcoal, sulfur and Dextrin together for 1 hour. Then add the 36 mesh Charcoal and firefly aluminum and mix with a spoon. Add water to make a dough mix and cut with a knife into 3/8" cut stars. Separate stars and dry for 3-4 days. The effect is a long tiger tail going up and firefly sparkles coming down. Larger stars take longer to dry, and a damp star produces very little firefly effect.

Potassium nitrate.................................49
Charcoal, air float...............................29
Charcoal, 36 Mesh.................................11
Sulfur............................................9
Dextrin...........................................10
Aluminum, firefly.................................5

The question is, i have all of those chemicals except the 36 mesh charcoal, i bought this charcoal instead http://www.pyrochemsource.com/Charcoal-White-Pine-WHITE-PINE-CHAR.htm

im not sure if its 36 mesh, so will this charcoal work for that star formula? if it doesnt work, is there any other star formulas that will work with the chemicals above? thanks for any advice!

[MadMat]

Pine charcoal is a good choice for this composition, but it needs to be on the coarse side for a lasting effect. I mean it will work, but if the charcoal is too fine the effect will be short lived. Is your pine charcoal noticeably coarser than the air float? If so give it a try. I have made similar formulas with as fine as 60-80 mesh and it still works OK.

Edited March 21, 2016 by MadMat

[MadMat]

One other bit of advice about charcoal stars. Pine produces a rather sparkly effect, but if you want real long hang time, 40 mesh hardwood charcoal is better. It will produce a bit duller tail though.

Another thing, don't be impatient with the drying time on stars of this type. They can take quite a long time to dry.

Edited March 21, 2016 by MadMat

[Fulmen]

The effect will change with the mesh size, but it should work one way or another within a fairly large range (say from half to twice the size). 36mesh is appr 0,5mm or 0,02", shouldn't be hard to ballpark the size by looking at it. The image suggests it's a bit on the coarse side, but without a scale it's impossible for me to say for sure. If it's way too coarse you could easily sift it to get a finer fraction or give it a quick run through a coffee mill.

[OldMarine]

That is a coarse charcoal. The last I bought ran from 30 mesh on down. It makes nice sparks!

UsaPyro has Southern Yellow Pine in the coarse mesh that is excellent.

Edited March 22, 2016 by OldMarine

[Bransen111]

Thanks for all the replies! You guys definitely put me at ease and I'm ready to make the stars, they'll have a good 5 days to dry also because I go back to work and won't be doing much other than working for the next week so no worries about that.

[Seymour]

A lot of people also ball mill similar charcoal star mixes. There is a lot of personal preference involved. I'm not saying that ball miling is what you should do, unless you want to try it.

 

But while different methods work for getting certain effects, which are preferred by different people, I'm just trying to say that whatever you do, so long as your KNO3 is fine enough, and you have the right amount of charcoal of some sort, you'll get a perfectly serviceable charcoal streamer star

Edited March 22, 2016 by Seymour

[schroedinger]

Yes you can make this mixes with a ball, and i would recommend it if you are pressing and use just a small ammount of water. But only mill for 15 -60 min depending on your starting material. If you use pet bedding straight from the tlud, add all execept the coarse charcoal, mill 30 min more bedding in the ammount of the coarse charcoalband mill 15 min.

Variances depend mainly on your charcoal. If you use airfloat and bedding only mill 15 min, if you use cooked up pellets expect a little longer.

[Bransen111]

Okay thanks for the tips, can anyone tell me what effect the aluminum in the formula will have?

[MadMat]

The firefly aluminum creates bright silvery sparks

[Arthur]

Charcoal makes orange sparks, aluminium makes white sparks, that formula will give you two colours in the spark trail.

 

What size charcoal you want really depends on the size (mortar size) of the intended firework. -A 2" bore mortar doesn't give much height so the coarse charcoal needs to be "not so coarse" so that it goes out before it hits the ground. With a 6" or bigger mortar you are going to have about 800 - 1000 feet for the falling stars to burn so the charcoal can be bigger, still you want the falling streams to end between 50 and 100ft above ground

 

With small bottle rockets perhaps some small stars would be a good start! Maybe I'd start at 4mm.

[Bransen111]

Ohh I see, I can't wait to see what they look like, does anyone have any good resources or links to show the differences between mesh sizes? Or is that something you just figure out along the way?

[Mumbles]

Here's a skylighter article that contains one of the original firefly formulas, and the modified formula you posted above. It has some additional details. http://www.skylighter.com/fireworks/making-fireworks-projects/firefly-aluminum-fireworks-stars.asp I've only used the formulas with 80 mesh charcoal, so I can't speak much to the one above. The article has some additional background on the 36 mesh formula though.

 

The firefly effect, or transformation effect, is one that starts as a charcoal streamer which has white flashes that emerge after a delay. The aluminum used is pretty important. Between poor quality stars and poor quality video, it's actually pretty hard to find a good example of this effect to be honest. This is basically what it's supposed to look like though:

[Seymour]

I just want to add that if you do use a ball mill, it's best not to mill anything with metals in it, so mix the Al in after ball milling

[Bransen111]

Thanks for the video that looks awesome! And Seymour thankyou!

[Arthur]

Shidlovskii describes stars like this as a faster burning body gluing together slower burning particles, so consider that the "glue" is the BP like parts from the formula and these need to be milled to burn reasonable quickly, the coarse charcoal and Aluminium needs to be of grain size selected for burn time -to make a tail that burns out before it hits the ground.

 

Maybe you could use airfloat for the body of the star and some selected mesh cuts for the tail. Here you will need a lot of charcoal and several mesh sieves. The mesh range will affect the style and character of the tail, but you should try to get the tail all finished by 100ft so that you don't burn parked cars or the local dry grass.