Crackle Microstars Made With Bismuth (III) oxide HD

[MinamotoKobayashi]

Since I do not want to manage poisonous mix that contains lead, I bought high quality high purity Bismuth Trioxide from

Pyrogarage and I want to make Dragon Eggs as cores for my stars.

I found this formula from Lloyd Sponenburgh:

 

Bismuth Trioxide: 0,71

Copper Oxyde, Black: 0,14

Magnalium 200 mesh: 0,1

Aluminum atomized 325 mesh: 0,05

 

Someone has already tried this formula?

What kind of binding agent You suggest?

And what kind of prime?

 

[Blackmach]

You can use the PDF formula changing lead tetraoxide by bismuth trioxide.

[Mumbles]

Most Dragon eggs are meant to be bound with NC lacquer.

[Aspirina]

I made it 2 times with very nice results with wood nc lacquer. Only need a bp prime.

 

Here one of my shells with this stars cut format:

[MinamotoKobayashi]

x Mumbles: I have the original LC laquer made for some musical instruments, but it is very dense.

In what acetone percentage must be dissolved?

 

Good result Aspirina!

What kind of method have You used to make the stars?
I found two methods from Pyrosource Wiki:

 

Manufacturing eggs by ricing (Example).

Once dampened with NC lacquer, push the mass through a 10 mesh screen quickly to obtain small granules resembling grains of rice. Try to keep the batches to about a 100 gram maximum or else the lacquer will probably dry before you get the stars screened. If the granules are intended to be primed, roll them in dry prime while they are still damp. If they are already dry, spray them with acetone to make them take up the prime.

Manufacturing eggs by crushing a dried mass.

Once dampened with NC lacquer, the mass is transferred onto a working surface e.g. a wooden board and rolled out to give a plate several mm thick. A few irregular cuts are made with a spackling tool or similar to give handier pieces for the next step. The rolled out mass is let dry as is. Drying won´t take long (probably several hours on a summer day) as the solvent evaporates very fast.

The dried pieces are then transferred into a stable container e.g. a bowl made of non-sparking (!) metal such aluminum and crushed by hand using a wooden tool (the handle of a rawhide mallet works well). A mask should be worn as the crushing operation produces some dust. Dragon´s eggs are quite sensitive to friction and, to a lesser amount, to shock. However, if we use the right tools the process is quite safe.

The resulting irregular grains are separated by size using screens. The best size for use passes 8 and is retained on 18 mesh and will look like colored 3FA (note that grains too small for use and/or dust are not wasted but instead may be stored and recycled/redissolved in a future batch). The grains produced by this method are very durable as well as easily ignited due to their sharp edges. However, the technique itself seems to be rather unknown among amateurs, although it (or a very similar one) is the one commonly applied commercially.

Edited May 19, 2019 by MinamotoKobayashi

[Aspirina]

The second one, In my opinion is not a good idea screen the composition when you mix all the chemicals with the nc lacquer, the mixture is very sticky to work it. The best you can do is make the mixture in a boul and then put it in a table and extend the mass with your hands (with globes) let it dry and then crash it in small pieces like 2/4mm personally I prime these stars with star roller, 1mm of black powder is enough Edited May 19, 2019 by Aspirina

[MinamotoKobayashi]

Star roller is suitable for rounded or cylindric stars, not for smashed pieces with flat surfaces and irregular edges.

Besides this, I need to have all the cores with the same dimensions.

My idea is to use 3mm gang pumps made by Zmuro.

It is not possible to replace NC laquer with other binding agents like phenolic resin?

[Aspirina]

Star roller is suitable for rounded or cylindric stars, not for smashed pieces with flat surfaces and irregular edges.

Besides this, I need to have all the cores with the same dimensions.

My idea is to use 3mm gang pumps made by Zmuro.

It is not possible to replace NC laquer with other binding agents like phenolic resin?

dont know you can try to mix the NC lacquer with acetone or alcohol

[Sulphurstan]

Minamoto.

I used to try a redgum based crackle, bound with alcohol. It was a success and a loud success 👍.

I'm currently out of my home for a week, and cannot access the formula, if you can wait until next Tuesday, I could send it to you.

[MinamotoKobayashi]

Hi Suplhurstan .. very interesting, I never hear that dragon eggs can be made without Bismuth or Lead !!

 

In the meanwhile I have found this interesting old thread:

 

https://www.amateurpyro.com/forums/topic/11523-easy-safe-crackling-stolen-formula-from-china/

 

If it works as shown in the video, it will be a nice cheap solution!

I already have HD Bismuth in my hands, so I will try it asap ...

[mabuse00]

 

My idea is to use 3mm gang pumps made by Zmuro.

 

That's something I've been thinking about for some time too. Making very small stars with consistent size is a job I could never accomplish in good quality.

 

But 3mm is still on the large side for DEs, also operating this kind of pump must be an unpleasant job, especially with sticky binders...

(thats what I expect...)

How about some kind of starplate... a starplate for 2mm stars. Or maybe some starplate-like pressing die that creates a pattern, like a block of chocolate, with predetermined breaking lines...

 

Would also be useful to make coloured microstars for fountains...

Edited May 21, 2019 by mabuse00

[Arthur]

There used to be a current thread "No NC dragons eggs" I can't search for it at the moment.

[Sulphurstan]

Hi Suplhurstan .. very interesting, I never hear that dragon eggs can be made without Bismuth or Lead !!

 

In the meanwhile I have found this interesting old thread:

 

https://www.amateurpyro.com/forums/topic/11523-easy-safe-crackling-stolen-formula-from-china/

 

If it works as shown in the video, it will be a nice cheap solution!

I already have HD Bismuth in my hands, so I will try it asap ...

Minamoto, The recipe I think about contains Bi2O3! just it is not NC bound, but redgum bound.

I found this formula on another (GREAT) forum, but I'm not sure it is the one I already succesfully tested (I can confirm next week). As you can see, Bi203 is in, but NC is out :-):

 

Bismuth trioxide 33.5%

Black copper oxide 33.5%

Magnalium 22.3%

Potassium perchlorate 6.2%

Red gum 4.5%

(Alcohol)

[MinamotoKobayashi]

I can try this formula tomorrow!

But .. the Magnalium mesh?

 

Also .. it is possible to replace red gum with phenolic resin?

I have a batch of phenolic resin cured with 8% of hexamine ... dried at 70 *C the stars usually become hard like steel.

Maybe interesting give a try ... maybe hardening the dragon eggs can create a louder bang?

Edited May 22, 2019 by MinamotoKobayashi

[Mumbles]

You'll probably have to dial it in. These comps are controlled by mesh or mixes of meshes of mostly MgAl, but I'm sure everything matters. I always like a mix of 200 and 100 mesh. Sometimes you need 60 or so for the best delay though.

 

Pressed does work, actually better in some cases since its denser. 3mm is large, but should probably be able to work.

 

Any substitutions like phenolic will need testing. Dragon eggs can be touchy and sensitive to seemingly minor variations. Test it out, and please report back.

[Sulphurstan]

I can try this formula tomorrow!

But .. the Magnalium mesh?

 

Also .. it is possible to replace red gum with phenolic resin?

I have a batch of phenolic resin cured with 8% of hexamine ... dried at 70 *C the stars usually become hard like steel.

Maybe interesting give a try ... maybe hardening the dragon eggs can create a louder bang?

Minamoto.

Back home, I can send you the formula I tested : it was was exactly this one:

 

Bi2O3: 30

CuO: 35,5

MgAl (100-200 mesh): 23,5

KP:6

RedGum: 5

Alcohol bound.

 

Have you tested something already?

[MinamotoKobayashi]

HI.

Yes, nothing works, I need to do more practice

 

For KP do you mean this mix:

 

https://pyrodata.com/compositions/KP ?

[starxplor]

HI.

Yes, nothing works, I need to do more practice

 

For KP do you mean this mix:

 

https://pyrodata.com/compositions/KP ?

 

Generally, in a comp listing, KP just means Potassium Perchlorate. Otherwise, it would be listed as "KP burst" (what your link is) or something similar.

[MinamotoKobayashi]

Thanks.

Today I will try to make cracking stars in the same way that I make common stars: rolling it in my star roller starting from a 2mm lead shot.

It is possible to add 5% of titanium to the mix to make the flower effect?

[Rmholbert]

Minamoto.

Back home, I can send you the formula I tested : it was was exactly this one:

 

Bi2O3: 30

CuO: 35,5

MgAl (100-200 mesh): 23,5

KP:6

RedGum: 5

Alcohol bound.

 

Have you tested something already?

I have used this formula substituting Red gum for phenolic resin at a 1:1 ratio. It does indeed work but if I'm recalling correctly Red Gum/Phenolic bound DE's do not seem, at least to me to be as loud as ones bound by NC lacquer. Still works, easy to make and a nice effect.

[Sulphurstan]

I confirm, the pops are not as loud as NC based mix.

The batch made recently is just a disaster (crispy crappy silent burn)😖😖.

I used the exact same chems as last time, maybe just too much alcohol for wetting?...

For me, I go back to NC bound mix, reliable, proven, efficient. Basta!

Edited June 11, 2019 by Sulphurstan

[Mumbles]

NC has a slightly negative oxygen balance. Phenolic is probably quite a bit positive. I wonder/bet you could mix in a little perc to counteract it. A member here, USApyro did some work on this in the past, and I think that was the trick.

[Sourdough]

I wish i could be sure what you mean by bound with NC Lacquer. Does it mean to use NC Lacquer in place of alcohol (presumably denatured alcohol) or do you use the lacquer in place of both the alcohol and the red gum, or does the lacquer replace the red gum, or am i missing the whole point? Id love to make these.

[Mraliksr]

Greeting Sir,

 

I have tried lead tetrooxide, bismuth trioxide and bismuth subcarbonate with megnalium nothing explode or crackling voice created

 

i used magnalium 150 to 200 mesh with all net formnula like copper oxide and magnalium 30 and 64 so becareful to perchase expensive chemical in bulk quanity first try in small quantity

 

thanks.

 

mraliksr

Edited March 30, 2022 by Mraliksr