Crackling microstars

[Bigfatorange]

Hi does anyone know if there is a difference in the loudness of the crackle in these two formulas

 

bismuth trioxide 37.5%

copper(II) oxide 37.5%

magnalium 25%

+10% NC

 

Bismuth trioxide 75

Magnalium (-200 mesh) 15

Copper (II) oxide 10

Aluminium (200 mesh atomized) 5

 

If so which one is louder

Thank you

[JeyJey]

Bi2O3 is expensive, hope that the first formula works

[BizzarePyro]

Hey I dont know how to post as Im new to this forum but, I was wondering if the ratio below would work for crackle micro stars

Bismuth triOxide - 35%

CuO - 38%

Mg/Al - 18%

KClO4 - 4%

NC - 5%

[Twesla]

Hey I dont know how to post as Im new to this forum but, I was wondering if the ratio below would work for crackle micro stars

Bismuth triOxide - 35%

CuO - 38%

Mg/Al - 18%

KClO4 - 4%

NC - 5%

My experience is extremely limited, so I cant offer insight as valuable as many other people here. I can tell you that Ive been experimenting with crackle a lot recently and that Ive had good results from 37.5 bismuth trioxide 37.5% cupric oxide and 25% magnalium bound with 10% nitrocellulose. I havent used another oxidizer in place of part or all of the NC before, but Im sure its worth a try.

 

One thing Ive noticed is that the 1-1 bismuth and copper oxide formula has a longer delay than the formula that calls for 70% bismuth if youre using the same mesh size of magnalium for both formulas. For the formula that uses less bismuth, you may use a finer mesh magnalium than youd be able to with the formula that calls for 70% bismuth. I made a 10 gram batch of crackle using 37.5% each of bismuth and copper oxides and 25% 230-325 mesh Mg/Al, and it was practically indistinguishable from crackle I made using 70% bismuth oxide 15% copper oxide 10% 80-200 mesh Mg/Al and 5% atomized Al (Eckart 120). Both batches were bound in 10% NC and were no more than 3mm in diameter.

[SharkWhisperer]

Hey I dont know how to post as Im new to this forum but, I was wondering if the ratio below would work for crackle micro stars

Bismuth triOxide - 35%

CuO - 38%

Mg/Al - 18%

KClO4 - 4%

NC - 5%

Hey Amigo. Probably nobody answered you for 10 days because they were waiting for you to do your expected homework. Study up on why the chemicals in DEs/crackle are in there and what they specifically do. Search the forum (and maybe others) for "dragon eggs" and "crackle" and "bismuth", for example. Compare the mechanics of DEs burning to the two phases of strobe formulations burning. Why you would put KCLO₄ into the mix--what exactly is it's purpose? Is it needed? Is perc commonly used in crackle comps? What's the oxygen balance of that mix? Balanced? Oxygen rich? Does the Mg and Al in your alloy both react identically with oxygen providers to form their combustion products? How do you think the crackle mix would burn if you just used pure Mg or pure Al instead of MgAl? What is the purpose of the bismuth compound? Why is it a good replacement for the more toxic (and cheaper) lead oxide from older formulations? Why two oxides? Anything reminiscent of a Goldschmidt combo in the comp? This information is mostly in the threads. You can just mix things together like a kitchen recipe, but it's more rewarding to be able to predict how changing one item might affect the outcome, and why. Nobody's expecting you to be a chemistry PhD overnight, but some chemistry knowledge is super useful when you're mixing energetic chems. You'll benefit from doing a little more background reading, and folks will be more receptive if it's obvious you've done some detailed research--there's a lot of easily accessible information. The "will this formula work?" approach might not be the best one to take. More impressive would be if you did some self-educated hypothesizing and maybe test a small batch yourself--then you can tell us if it works (and works the way you want it to).

 

Well-tuned comps have specific ratios of specific chems for a reason. Suggest not trying to reinvent or improve the wheel before you learn the basics of the tried-and-true established formulations, so you're branching off from a proven starting point. Then change only one parameter at a time. And all MgAl is not the same, so nobody can really comment unless they know the particle size of your metal, which is a critical factor in deciding how big to cut your DEs (that is assuming it is a 50:50 alloy).

[SharkWhisperer]

My experience is extremely limited, so I cant offer insight as valuable as many other people here. I can tell you that Ive been experimenting with crackle a lot recently and that Ive had good results from 37.5 bismuth trioxide 37.5% cupric oxide and 25% magnalium bound with 10% nitrocellulose. I havent used another oxidizer in place of part or all of the NC before, but Im sure its worth a try.

 

One thing Ive noticed is that the 1-1 bismuth and copper oxide formula has a longer delay than the formula that calls for 70% bismuth if youre using the same mesh size of magnalium for both formulas. For the formula that uses less bismuth, you may use a finer mesh magnalium than youd be able to with the formula that calls for 70% bismuth. I made a 10 gram batch of crackle using 37.5% each of bismuth and copper oxides and 25% 230-325 mesh Mg/Al, and it was practically indistinguishable from crackle I made using 70% bismuth oxide 15% copper oxide 10% 80-200 mesh Mg/Al and 5% atomized Al (Eckart 120). Both batches were bound in 10% NC and were no more than 3mm in diameter.

Twes hey, just to say you could probably cut that NC final content in half to the more usual 5% (or possibly even a little less) and not see much of a difference--it's a bitch waiting around for all that acetone to evaporate from the amount of NC lacquer needed to add 10% NC final mass! That is what your formulation indicates, right? Or is it just mixing your dry chems with whatever quantity of 10% NC lacquer it takes to get the dry chems into a damp ball? Big difference. Good observation on the MgAl particle size change.

[Twesla]

That is what your formulation indicates, right? Or is it just mixing your dry chems with whatever quantity of 10% NC lacquer it takes to get the dry chems into a damp.

I have a pre-made solution (more like a gel) of 10% w/v NC in acetone that I keep in my chemical mini freezer, but since the gel can no longer flow, I scoop out the amount I need and measure the weight. Since acetone is less dense than 1g/ml, I weighed out 9 grams of gel before mixing. The kicker is that the NC is homemade, and the only testing I do is to light a small piece to ensure it ignites instantly with no residue, which only tells me that it will dissolve completely. It lacks the stabilizers present in double base smokeless powder, which I cant find anywhere for the life of me. Thank you for the feedback, every last tidbit is appreciated!

[SharkWhisperer]

I have a pre-made solution (more like a gel) of 10% w/v NC in acetone that I keep in my chemical mini freezer, but since the gel can no longer flow, I scoop out the amount I need and measure the weight. Since acetone is less dense than 1g/ml, I weighed out 9 grams of gel before mixing. The kicker is that the NC is homemade, and the only testing I do is to light a small piece to ensure it ignites instantly with no residue, which only tells me that it will dissolve completely. It lacks the stabilizers present in double base smokeless powder, which I cant find anywhere for the life of me. Thank you for the feedback, every last tidbit is appreciated!

Good on the NC.

 

But for stabilizer, you must not have looked too hard. Diphenylamine (not phenylalanine!). It's a weak base. Can buy it on Amazon... Here's one w/free delivery; took 5 seconds: https://www.amazon.com/Diphenylamine-99-93-Analytical-Reagent-ACS/dp/B07GMV3949/ref=sr_1_4?dchild=1&keywords=diphenylamine&qid=1625686904&sr=8-4 . Take an extra minute and get it cheaper. Probably Ebay, too. Or from any of many chem suppliers. Stuff's toxic. Read up on it. You don't need much--smokeless MSDSs may give an approximate amount, or keep researching--it's published. There are other stabilizers too, but this one's pretty commonly used. Homemade NC is notoriously unstable and fast-degrading. The freezer storage helps.

 

"9 grams of gel" means nothing if you don't state the total amount of comp it's going into.

 

Unsure why, if you're in the US and 18 y/o, you're having trouble locating smokeless powder. Less regulated than black powder. Flammable, not explosive. Cabellas or any local gun store. Armslist.com or similar. Unless you're living in a nanny state that requires an FID card to buy even lead musketballs. Maybe many reloaders have stocked up and shorted the market. Where there's a will there's a way. Looking up "double-base smokeless powder for sale" online should point you in the right direction? Much easier (and cheaper) than making your own with a limited lifespan. Plus, you get an extra bonus of some slightly more brisant NG. If possible, buy the thin fast-burning wafers for shotgun shell reloading--dissolves faster than extruded pellets for magnum rifles etc... Maybe $15-20/pound, but more is possible if folks are hoarding it...

 

Pyrochemsource has it in stock for $16/lb but it isn't stabilized either. https://www.pyrochemsource.com/Nitrocellulose_p_120.html

[Twesla]

Youre right about me not looking very hard for stabilizing ingredients, because I didnt look at all. I wasnt really aware of significant deterioration being a concern until very recently: I assumed it was more of a long term storage problem. As for my inability to access double base shotgun or pistol reloading powder, theres a crazy shortage right now. None of the online sources (that Ive browsed so far) have it in stock, nor have I been able to find it locally. Even my boss whos in with all the local gun enthusiasts and ammo suppliers has been unable to score even a pound for me. I just assumed this is a temporary issue and Ive only been doing a couple of small scale comparison tests recently, hence the mention of using an aliquot of 9 grams of 10% w/v NC/acetone added to the 10 gram batch previously mentioned.

 

I really appreciate both the suggestion of diphenylamine as a functional stabilizing agent and even more, the use of wafers over extruded pellets in terms of preferential workability. While I have you here, Im not sure if youve seen some of the more premium crackling fountains people have been using this Independence Day season, but Ive seen more than one where each individual pop sprays long, bright titanium sparks spherically around the origin. Ill try to link a video of an example, but Im merely curious if youre familiar with this effect and/or if you have any ideas or insight into how something like this is accomplished. My only guess is that its some sort of melt layer thin enough to keep the star particles small, but drossy enough to hold the titanium required to create such brilliant streaks of light. Either way, thank you for your input and direct interaction!

[Twesla]

https://m.tiktok.com/v/6981616595252579589.html?_d=secCgYIASAHKAESMgowvh1kFdx4F6PehL61lRzaw3EY%2FJpuJSHtMzh4TZPdYR1TQk8FizGa1qxudhmZ738FGgA%3D&checksum=b7f0f950d85578e90e769d6dde73b69a92937e21334578482ab36e6042d1ca8a&enable_clips=1&language=en&preview_pb=0&sec_user_id=MS4wLjABAAAAtSUwTpUiSG7G1NGoKfxn2FXq0yHkQ1Ras7EKUq_atowIPfHoh2j9UHanUdeMvlEE&share_app_id=1233&share_item_id=6981616595252579589&share_link_id=70145014-1EC8-4DE9-8EDB-8E2DC24CDBF3&source=h5_m&timestamp=1625688752&tt_from=sms&u_code=defha4dm0i7488&user_id=6874292216576902149&utm_campaign=client_share&utm_medium=ios&utm_source=sms

 

Heres an example of what I mean. I have my own video and a few photos as well that Ill upload a bit later. Basically, when the pikachu begins firing crackle, each pop is a massive dandelion ball of silver streaks.

Edited July 8, 2021 by Twesla

[SharkWhisperer]

https://m.tiktok.com/v/6981616595252579589.html?_d=secCgYIASAHKAESMgowvh1kFdx4F6PehL61lRzaw3EY%2FJpuJSHtMzh4TZPdYR1TQk8FizGa1qxudhmZ738FGgA%3D&checksum=b7f0f950d85578e90e769d6dde73b69a92937e21334578482ab36e6042d1ca8a&enable_clips=1&language=en&preview_pb=0&sec_user_id=MS4wLjABAAAAtSUwTpUiSG7G1NGoKfxn2FXq0yHkQ1Ras7EKUq_atowIPfHoh2j9UHanUdeMvlEE&share_app_id=1233&share_item_id=6981616595252579589&share_link_id=70145014-1EC8-4DE9-8EDB-8E2DC24CDBF3&source=h5_m&timestamp=1625688752&tt_from=sms&u_code=defha4dm0i7488&user_id=6874292216576902149&utm_campaign=client_share&utm_medium=ios&utm_source=sms

 

Heres an example of what I mean. I have my own video and a few photos as well that Ill upload a bit later. Basically, when the pikachu begins firing crackle, each pop is a massive dandelion ball of silver streaks.

Cool crackle effects. Try adding some spherical Ti to your crackle. Ned Gorski has a video somewhere showing his addition, but those were more along the lines of loud brisant DEs vs more tame, quieter, softer exploding crackle. Might need to adjust your base comp to get the burst characteristics dialed in.

 

The fountain base doesn't appear to be BP based or you'd expect to see more smoke and orange flame; probably a slow perc and/or barium nitrate comp. The non-crackle sparks from the fountain appear to have an orangey tint. This could be if they used FeTi in the matrix instead of pure Ti or it could also just be the camera's take on things. Hard to tell. So overall it looks to me like the base matrix contains metal and layers of it contain both metal and crackle microstars containing Ti, probably with a reasonably thick prime.

 

Simple to test out various small batches of different comps. I'd make a non-charcoal fountain matrix with Ti or FeTi to try to match the sparks, while separately trying to develop Ti-containing crackle that burns with those trails that are very cool, tuned for sparks vs explosion. I would adjust the strobe/smoulder oxidizer relationship first to tone down the crackle brisance and then start adding various fractions of Ti to the crackle mix until I got microstars with the desired effect. Then it'd be a simple matter to add them to the fountain matrix, whether throughout or just in layers as it appears to be the case in the gerb in the video.

 

Need to adjust microstar size and matrix burn characteristics to nozzle selection to get a nice powerful exhaust that doesn't risk slagging up and clogging the nozzle.

 

But that's a cool fountain and worth trying to replicate.

[Twesla]

I really appreciate you taking the time to add your insight to this! Your observation of how clean burning the base comp must be is extremely helpful, too

 

The very first time I attempted to make a crackling gerb, the base comp was too hot and was launching roughly half of the microstars out without igniting them. I came across a video from Yus Fireworks where they were testing different microstar formulas in a cooler matrix, so with a cooler base composition and a bit of prime added to the crackle I was able to get a satisfactory basic effect that I was going for.

 

By the way, that YT channel seems to have disappeared recently. Yuss work was great, and the composition ingredients were always generously listed in the video description section. I try to avoid YouTube for any how to advice since someone could easily share mixtures or process techniques of questionable value and safety, but there are exceptions, e.g. Ned Gorskis channel.

Ill be sure to post an update if I manage to make any significant progress in achieving a result that is closer to emulating the effect in the video I posted. Thank you again for your reply!

Edited July 8, 2021 by Twesla

[SharkWhisperer]

I really appreciate you taking the time to add your insight to this! Your observation of how clean burning the base comp must be is extremely helpful, too

 

The very first time I attempted to make a crackling gerb, the base comp was too hot and was launching roughly half of the microstars out without igniting them. I came across a video from Yus Fireworks where they were testing different microstar formulas in a cooler matrix, so with a cooler base composition and a bit of prime added to the crackle I was able to get a satisfactory basic effect that I was going for.

 

By the way, that YT channel seems to have disappeared recently. Yuss work was great, and the composition ingredients were always generously listed in the video description section. I try to avoid YouTube for any how to advice since someone could easily share mixtures or process techniques of questionable value and safety, but there are exceptions, e.g. Ned Gorskis channel.

Ill be sure to post an update if I manage to make any significant progress in achieving a result that is closer to emulating the effect in the video I posted. Thank you again for your reply!

Yus does good work. He's posted some of his videos and comps on this site that might overlap with what he had posted on Youtube. Crackle/DEs need a hearty priming, and thicker prime will take a moment longer to burn through and prevent the star from blowing inside or immediately above the tube exit. Remember that elevated pressure inside the gerb will enhance matrix burn speed, with some comps more affected than others. And pressing density of the comp in the tube can temper this. Most gerbs benefit from tamping/pressing but generally nowhere near the pressures used for pyro rocket BP propellant grains.

 

Are your DEs sensitive to impact? Hopefully it won't take a tube exploding in your hand while pressing/ramming for you to find out. I often use cheap wood tools/dowels to compact gerbs, especially containing metals. Oak dowels are cheap and easy to shape. And effectively disposable. I have gerb spindles for metal tooling, but that's expensive and limited to use with certain comps. Smack a microstar with a hammer and see what happens. Wearing full PPE, of course...