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Dragon Eggs (Dragon Flowers)


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#61 SharkWhisperer

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Posted 28 March 2021 - 09:36 PM

These are badass,nice stuff.

Yus creates respectable stuff. All the time. Own YT channel. Good info. Shares comps, too,


Edited by SharkWhisperer, 28 March 2021 - 09:37 PM.


#62 Yus

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Posted 29 March 2021 - 01:50 AM

Thank you. I use core comp. CuO - 40%, Bi2O3 - 30%, AlMg - 30%.



#63 ronmoper76

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Posted 29 March 2021 - 05:14 PM

I'm definitely gonna try it. I have been searching for different ratios that work with varying amounts of Bi2O3. Its kinda pricey here to be using 75% like a lot of formulas call for.



#64 SharkWhisperer

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Posted 29 March 2021 - 11:10 PM

 

Wow have been offline for a few days, but here's my reply anyway... I use this same formula too. MgAl is 150 - 200 mesh. Meanwhile i found a way to get the grains less porous. After drying i sieve them to get the small material out, the bigger ones are hand-rolled in a bowl with another layer of material. This produces more dense grains. I should try coarser MgAl too, sound promising! 

I'd use coarser MgAl; used to use FWC's old -60 mesh that had fines, too, and it works great. He's resized his selection and now I believe -50 and -50+100 is available--I'd probably try the latter first. 10 mesh seems too large to me, both for burn characteristics and ease of use. I think a lot of people make the mistake of using too fine of MgAl to begin with (150-200 wouldn't be my initial "go to" selection). But whatever works for you.

 

schroedinger, I was referring to aluminum. Not mgal! :)

Got 10-100mesh mgal that I will try, this is coarse enough (if not too coarse...).

Please see comment above--10 mesh might be a thorn in your side. The -40+100 fraction of your metal is what's doing the work. Simple to smash down with a hammer (no milling necessary) and rescreen to desired fractions...

 

Will try to roll them further spitfire, sounds like a good idea. I only granulated them, to create very porous granules! These obviously don't make great dragon eggs.

By the way, all I have is 400 mesh spherical aluminum. Anybody knows if this is a critical detail?

One thing I have never yet experienced is "porous" DEs!!! Heavy little dense bastards, they are!!! Solid. Maybe in the mixing/consolidation? You don't want to "granulate" them similar to how you might rub a ball of moist BP across a 1/4" or 1/8" screen. You can easily screen cut them, but you need to get your patty the right thickness first, and then press downwards more than rub across the screen, if that makes sense. Hot/combine prime the tops and bottoms of your slabs thickly before screening (or cutting), maybe with  a spritz of acetone first to rewet the surface and help it stick, and then drop them into more hot/combined prime immediately after making them into little squares. Be generous with the prime--they work better, though for the life off me it seems that the Chicoms don't worry so much about this. Probably using H3 as prime base (haven't tried, but see no good reason to try; suggest go with what's proven in the West)... Secondary prime at leisure. Hot but slower burning than the first hot prime, but with some extra retained heat (Si and Al or MgAL extra). Priming will definitely depend on whether your're making gerbs (gorgeous) or aiming for crackle core stars (now priming becomes critical). The priming approaches for different uses are not interchangeable, for obvious reasons besides working with a difficult-to-ignite comp.

 

Small sizing is generally good with DEs--maybe you'll figure a way but my DEs are around 1/8" (3 mm?) before priming in general, for ground effects and for aerials. They work great. Can make themmuch  bigger, but with my MgAl mesh sized, they'd likely just blow apart (probably blind). Still amazes me that the Chicoms make consistently functional (and decent) perfectly round primed DEs that are only 2mm diameter max. But they're likely using the better characterized (and toxic--how often are imported 1.4g devices actually dissected and tested by the supernanny CPSC?) lead comps to start with, and have an endless labor supply for when the first group of 12-year-old "technicians" occasionally go boom ("grease fire in kitchen, no ploblem! Evlyting unda contlow!").

 

400 mesh spherical sounds big--even larger than Al in Tannerite. That's an average particle size of 37 microns, which is rather large for spherical. Might work. Might be an impediment. Everybody's seen them, but sometimes it's useful to review the mesh-to-micron sizing chart (https://www.skylight...onversion-chart ), keeping in mind that you're referring to average size, and each batch, even from the same company will vary on either side. You can't screen sort 5 vs 40 micron--it's all dust. I use 5 micron spherical Al addition to my DE mix, with great results. It keeps the fire alive. Larger would probably work. 37 micron average? Wouldn't be my "go to" add-in Al size, but definitely worth comparing.

 

Save a lot of money by swapping (to your chosen extent) the classical 75% Bi2O3 for CuO (and vice versa). DEs will work essentially identically with this change (you might need to tweak your other chems, slightly, but not much). And at $20/lb vs $8/lb, I prefer using more CuO than that pretty yellow (and dense as hell) bismuth.

 

I used to add and add and add NC lacquer until I got a final estimated NC concentration of 5%, but seriously question if you need so much--I get solid DEs that perform well using just a single thorough wetting with 5% double-base/acetone (maybe just a little extra for good luck--it dries fast anyways). Turn a 2 hour production into a 45 minute production (not counting clean-up and secondary priming). And prime them lil' bastards well. I step prime with a hot 50:50 comp/hot prime mix (with a few % silicon and Al, Mg/Al if it's closer) and then a slower cover prime, also with silicon and another metal, just because, and they never fail to ignite. I don't bother with roughing the surface by including sawdust or diatomaceous earth--just never found it necessary.

 

Easy peasy. Chris at FWC is selling a variety of screen-sized MgAls these days. I used to love his -60 (no lower cutoff, so plenty of fines), but given the importance of your MgAl sizing, my next batch will be more tightly regulated--likely his marketed -50+100 or so. Those using -200 MgAl in crackle kinda catch my attention, but if it works, great. Once you have all the parameters pinned down, it's hard to screw it up and fast to whip up a batch... It dries quickly and I prime slabs wet before screen or hand-cutting. If this makes you nervous, then have some acetone at hand and you can back up a few steps no problem (if spraying, make sure it doesn't dissolve the sprayer contents--various plastics used in the sprayer vs the bottle...). And if you need even more time, then add some MEK (methyl ethyl ketone) from any big box store (Home Depot etc), which will slow the evaporation rate quite a bit. I've personally never found this necessary. NC/acetone comps tend to get "sticky", and some have suggested that adding 10% or so of alcohol (ethanol, isoprop, methanol/denatured...I don't care), can reduce this, though I've never found it necessary.

 

Crackle away!!!  Birth them thar Dragons!!!

 

p.s. Yus has on several occasions posted the size of his MgAl and other chems used in DEs and similar crackle comps, so please search/read these before you bug him with a "hey, what size MgAl do you use" query that you can answer for yourself. If he changed it from earlier postings, he'll let you know. TIP: You'll need your handy micron-to-mesh table to retranslate Yus' descriptions back to mesh size...


Edited by SharkWhisperer, 30 March 2021 - 01:03 AM.





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