I have never seen stars with a such strange shape!

[MinamotoKobayashi]

I have always created stars with my star roller in the same way: I started with 1,5mm lead spheres, I created strobe cores, I slowly dried the cores without heat, and then I applied around the desired comp.

And always I obtained a near perfectly rounded star shape.

This time I obtained this kind of stars:

 

What the hell ??!?

This is the most bizarre star shape I've ever seen!

Another strange thing is that almost all the stars have the same weight. Usually it is impossible to make stars with the same diameter in the same batch.

I must admit, with this crazy shape I can fit more stars into the hemis because there are less empty spaces between them, but I cannot predict if the break will be simmetrical as happens with rounded stars.

The only two factors different from the previous batches are:

 

1. I used only water and few drips of alcohol because these are willow stars (usually I use 70% water 30% alcohol for every kind of stars);

2. I ballmilled the chems together for some hours in my ballmill (without metals of course) soaked in pure ethyl alcohol, dried the mix and finally

granulated with a 20 mesh woven wire.

 

But I think it is impossible that the above two factors have contributed to change the stars in a so stranger shape .. any ideas ??

Edited April 6, 2020 by MinamotoKobayashi

[memo]

looks likes your cores stuck together, to wet. then it looks like you might have put too much comp on them. raspberry stars. if you toroed them they will round out

[Mumbles]

Those are normally called "raspberries". They come from uneven wetting of the composition you're trying to roll. This is pretty common with high charcoal compositions if you're not experienced rolling them. You have to be a lot more patient when rolling just from how long the high charcoal comps can take to absorb and evenly distribute water. If you try to add the comp before water is distributed evenly, this is what happens. Basically there are "pockets" of wet and dry (or at least wetter and drier) on the surface. These wetter areas take up composition faster and cause the comp to be taken up less evenly. These then wetter, higher bumps are the first to take up more water and more composition and the effect is more pronounced over time.

 

If you notice this happening the best thing to do is just let the stars roll themselves out. Get them wetter if needed, but give them time. With ample rolling time the bumps will usually smooth themselves out. The toro method is also helpful as the composition is already given time to fully wet. More alcohol may help to some degree as well.

 

I would not count on those stars giving a totally symmetrical break if they're not smoothed out. When shells are broken as hard as yours, the aerodynamics really start to affect things. If you made a poka or a horsetail type shell, they'd be great though.

[BetICouldMake1]

I've not rolled stars, but I've read that using a very fine comp can lead to raspberries. It could be your ballmilling is the culprit.

[robbo]

Patience? When rolling stars? Like delayed gratification, I am familiar with the term but have no personal experience with it.

[MinamotoKobayashi]

Many thanks dudes, even today I learned something new!

Edited April 6, 2020 by MinamotoKobayashi

[SKC]

Seems the cores have adhered to each other. One must start with managebly adequate quantity of stars. Same thing happened to me earlier also. Another reasone could be over wetting a particular area or the sprayer is not throwing water as mist. You might consider adjusting the spray bottle nozzle if required.

[Arthur]

I watched Kimbolton Fireworks roll stars once each operator had several water sprayers, of their own chosen fineness. Some made droplets and some made just a fine mist. Mostly the droplet sprays were used for starting coreless stars and the ultra fine misters were used for building comp onto stars. It's all in the moisture content and the way it's applied.

[ExplosiveCoek]

Mumbles is correct here. The cores have nothing to do with it gent's .

[hcb]

looks likes your cores stuck together, to wet. then it looks like you might have put too much comp on them. raspberry stars. if you toroed them they will round out

^^^ What he said.

 

I've rolled very few stars, being new to fireworking, but I've screwed some batches up which gives me firsthand experience from which to speak. When they're lumpy and bumpy they're called "raspberries" because they kind of look like raspberries and it's a handy term to refer to a condition which communicates the problem quickly. In the book by Bleser on making shells and round stars he calls it "spiking" but it seems that term (his book is from 1988) is relegated to history and "spiking" now seems to refer to wrapping shells/cannisters with string to reinforce them.

 

Back on topic. Having screwed up more than once...I would agree that Memo is right, it looks like the star seeds clumped. When I get raspberries (often) they're more rounded with more and smaller bumps than these. I'm no expert, but, having messed up a few batches and seeking information to correct that I have some ideas (and a new motor and speed controller for my roller which should be here today so my progress has been held up for a bit): If you're using a binder such as dextrin, it has been reported that using a higher percentage of alcohol in the mix when the star seeds/stars are small will help reduce raspberries. This is because, reportedly, the water "activates" the dextrin, so, less water, less sticky dextrin, less likely to hit and stick right there and not move. Another thing is touched on by Memo here, too fine powder used. One source...maybe Bleser's book but I may be confused, suggested using 100-200 mesh granulated dust (granulate then ball mill shortly to get that size). I've been using stuff straight out of the ball mill and getting mixed results. I started rolling stars and immediately having problems with raspberries. That journey, to solve that problem, quickly led me to replacing the drive on my roller and waiting for parts. So...I've not gotten to try that yet.

 

Evenness of the moisture is important and, before I shut down to re-motor my setup, I did experiment with adding solvent and then waiting a minute or two before adding comp. This seemed to help but involves something called "patience". I tried to find where I could download some of that but it wasn't in the first link that popped up. I'm kind of SOL. But, I think that will help.

 

A tip from a guy who posts on YouTube under PyroHook: go to Wal-mart and buy a Febreeze One sprayer. It's a non-aerosol sprayer but dispenses almost like an aerosol sprayer. The lid/sprayer is removed by about 1/4-1/3 turn lefty loosey, it has detents so you'll have to overcome that grip. Dump the Febreeze out and add your water or H2O/alcohol mix in. The sprayer is a Flairosol unit (it's marked/embossed on the unit below the spray head). The sprayer full of Febreeze at Wal-mart is $4.94 with a brand-name Flairosol sprayer. The sprayer bottles, in pairs, also branded Flairosol, on Amazon, empty, are about $15-18/pair. They dispense a *very* fine mist which makes it easier to 1) get even distribution of the solvent on the stars and 2) not flood the stars. I have 4 of these sprayers now: H2O, 70/30 alcohol/H2O, 50/50 alcohol/H2O, and one I'll try putting acetone in but haven't yet.

 

https://www.walmart.com/ip/Febreze-One-Fabric-Air-Freshener-Mist-Starter-Kit-Orchid-10-1-fl-oz/121664040?athcpid=121664040&athpgid=athenaItemPage&athcgid=null&athznid=PWVUB&athieid=v0&athstid=CS004&athguid=27b5f941-95c-171a78d3362e9e&athancid=null&athena=true

 

FWIW.

 

--HC