Bismuth Dragon eggs size

[Todd]

What is the best size to make the bismuth dragon eggs? I have been using a 4 mesh screen giving me eggs approx 1/4 square but I am thinking this is too large

 

When lighting on the ground I get some chunks which shoot away from the main mass amd do not ignite

 

When firing from a shell I get some fallout i can hear of unlit eggs

 

The majority of each egg lights and pops with a nice bang but I still see some fallout, is this due to size?

 

Comp is

Bismuth trioxide 37.5

Copper oxide black 37.5

Magnesium 200 mesh 25

Nc laquer made from double base smokeless

[Carbon796]

I want to say its around 8 mesh or so. But, I don't really follow the DE threads that closely. Usually formulas from a reputable source, will spec that kind of information.

 

If you search FW'ing or Ned gorski on youtube for crackle or DE. You'll probably find some useful information.

Edited February 27, 2022 by Carbon796

[deepakpyro]

I faced similar issue on DE which made by passing DE dough through 6 mesh. On surface it performed good with blow torch however in star gun it went blind without pop. I would recommend 8 mesh for 3inch shell and 12 mesh for inner core of starts or 2.5 or 2 inch. Edited March 1, 2022 by deepakpyro

[Richtee]

I was intrigued by this. Picked up the chems and played around. A length of visco dipped in NC lacquer and rolled in it is fun

[Uarbor]

I was thinking about getting into some crackle myself. I just made my first experimental small batch of NC lacquer. I was going to make some e matches with it to get used to working with it. When you guys put the crackle Stars through a screen are they sticky? Do you prime them with BP and silicon or a perc based Prime?

[SharkWhisperer]

I was thinking about getting into some crackle myself. I just made my first experimental small batch of NC lacquer. I was going to make some e matches with it to get used to working with it. When you guys put the crackle Stars through a screen are they sticky? Do you prime them with BP and silicon or a perc based Prime?

I usually hand cut instead of screen cut because they're pretty sticky. Best to use a step-prime. First layer is a hot perc prime (add some Al and Si), which I usually spread atop the moist patty (both sides; gotta flip it once) before cutting so it sticks right on. After cutting, I sprinkle another handful to get the sides where cut. Second prime is a slower BP base with acetone or alcohol soluble binder (can use water/dextrin, but I like quick drying). Usually I spray heavily hot-primed cut stars with a few layers of slow prime in a bucket or dish so they round out as they build up layers. Essential to get a good prime layer on DEs because the comp doesn't ignite easily...they're no charcoal stars for sure. But it's pretty straightforward. There are several threads here with specific primes and processes detailed, including mine, that work reliably.

 

Longest part is if you actually try to get a final NC concentration of 5% in your comp instead of a lesser amount as just a binder and less as a component, because you need to add a lot of 10% NC lacquer to get that quantity, so there's a lot of acetone that needs to evaporate. That said, I've done it both ways--NC to 5% and NC to 1% both work well for me. But the second way is a lot faster. You can bet the Chicoms don't use NC as their DE binder--probably a phenolic resin. I started playing around with phenolic DEs and was getting there but got sidetracked.

 

If using pure acetone as solvent, it's handy to have a spray bottle at hand to keep comp surfaces moist because it evaporates so quickly. Test your sprayer first; while most HDPE bottles are spray resistant, the plastic in the nozzles/spray device are not necessarily acetone resistant and might clog up on you unexpectedly--best to know ahead of time. Can slow evap time/increase working time by adding some MEK or paint thinner to your acetone, if desired, but I don't bother.

 

DEs are a ton of fun, both for aerial and ground devices. Chris at FWC is selling BiO₃ for $15/pound these days, which is the cheapest I've ever seen it at the pound level (probably to offset the necessary price increase in CuO this year...).

Edited March 31, 2022 by SharkWhisperer

[Uarbor]

I usually hand cut instead of screen cut because they're pretty sticky. Best to use a step-prime. First layer is a hot perc prime (add some Al and Si), which I usually spread atop the moist patty (both sides; gotta flip it once) before cutting so it sticks right on. After cutting, I sprinkle another handful to get the sides where cut. Second prime is a slower BP base with acetone or alcohol soluble binder (can use water/dextrin, but I like quick drying). Usually I spray heavily hot-primed cut stars with a few layers of slow prime in a bucket or dish so they round out as they build up layers. Essential to get a good prime layer on DEs because the comp doesn't ignite easily...they're no charcoal stars for sure. But it's pretty straightforward. There are several threads here with specific primes and processes detailed, including mine, that work reliably.

 

Longest part is if you actually try to get a final NC concentration of 5% in your comp instead of a lesser amount as just a binder and less as a component, because you need to add a lot of 10% NC lacquer to get that quantity, so there's a lot of acetone that needs to evaporate. That said, I've done it both ways--NC to 5% and NC to 1% both work well for me. But the second way is a lot faster. You can bet the Chicoms don't use NC as their DE binder--probably a phenolic resin. I started playing around with phenolic DEs and was getting there but got sidetracked.

 

If using pure acetone as solvent, it's handy to have a spray bottle at hand to keep comp surfaces moist because it evaporates so quickly. Test your sprayer first; while most HDPE bottles are spray resistant, the plastic in the nozzles/spray device are not necessarily acetone resistant and might clog up on you unexpectedly--best to know ahead of time. Can slow evap time/increase working time by adding some MEK or paint thinner to your acetone, if desired, but I don't bother.

 

DEs are a ton of fun, both for aerial and ground devices. Chris at FWC is selling BiO₃ for $15/pound these days, which is the cheapest I've ever seen it at the pound level (probably to offset the necessary price increase in CuO this year...).

thanks for all the info. I think my first attempt is going to be some crackling micro Stars in a matrix comet. I am coming up on my 1 year anniversary in Pyro. Hard to believe I came here to save a few bucks making my own black powder and now I'm into this hobby for thousands of dollars LOL multiple sets of Rocket tooling and a press and I seem to have a chemical collecting Obsession LOL needing some the Bismuth trioxide give me an excuse to make another big order to "save" on shipping.

[SharkWhisperer]

thanks for all the info. I think my first attempt is going to be some crackling micro Stars in a matrix comet. I am coming up on my 1 year anniversary in Pyro. Hard to believe I came here to save a few bucks making my own black powder and now I'm into this hobby for thousands of dollars LOL multiple sets of Rocket tooling and a press and I seem to have a chemical collecting Obsession LOL needing some the Bismuth trioxide give me an excuse to make another big order to "save" on shipping.

Cool beans. Microstars/mouse turds are harder to make than bigger stars, but if embedded in a matrix you don't really need to worry about the prime so much, so that makes things simpler. If I was going for tiny, then I'd probably screen them through a 10-mesh or so and maybe hand-roll them to rough spheres while still damp (spray bottle...).

 

Think I settled on 35:35:25:5 for my go-to recipe, with the first two being oxidizers, the third MgAl (generally use -60 or -50 mixed mesh), and 5% dark pyro Al (need to check notes; think it's worked equally well with 5-micron atomized and smaller flake Indian dark) to get the fire cooking. The MgAl sizing is key, and generally you want a smaller mesh for smaller DEs. With the range of MgAl sizes I use, it seems to work fine with 1/4" to 1/8" sizing (haven't gone much outside that, though the smaller scraps still blow in the firepit). Many recipes omit the Al, use 200-mesh MgAl or so, and are BiO₃ heavy, but my combo works fine for me.

 

DEs are a lot of fun and addictive. Heavy, too.

 

Yes, something always can be added to the chem/tooling/supply shopping list to "save" on shipping, tsk tsk. I'm the same way with fireworking chems and finned rockets, too...