I don’t have any questions, but I do want to thank you, as one individual among many, who have positively impacted my life: mine, my wife, our families, friends and loved ones over the year. Thanks!
Thank you, there is so much crap on UA-cam, but this is the kind of stuff that keeps me going. A great video with industry information presented in an understandable manner by a guy that is obviously at the top of his profession. And let's not forget, no annoying music, thank you for that as well.
Thank you something I wish there was more of these days on UA-cam and that's videos that are informative, not dumbed down, nor highbrow either that are presented by someone who knows what they are talking about! And not only that but then someone that is willing to take the time to share some of what he knows without music that makes you want to dig your ears out lol So thank you on many fronts! I have always thought that I would love to do what you'll do for living and after hearing all that you just explained I think I wood be quite capable of and enjoy doing so..... now if only I'd been born into one of the families in my part of the world that seem to control the larger end of the market.... Ohh well I can dream 👍 Keep up the amazing work! Cheers
Theyre safer because there isnt a big rocket hauling at anyone sideways if things go wrong. Mortars throw everything up and there is no big stick to drop from the sky afterwards either :)
I noticed that in this video the launch charge was very loud but at a professional fireworks show it sounds very subdued. Sometimes you can hardly hear it and I've always wondered how they are launched into the air and why it sounded that way. It sounds like a big puff of air and my guess is it's not very loud because it's down in a tube.
It sounds subdued at a professional display (if you can hear it at all) because the audience is a good distance away from where the shells are being fired, a safety requirement outlined by federal and local laws. The mortars are very loud, it is literally like a cannon firing a cannon ball. The pyro crew is much closer, which is where the footage you are referencing was shot from. The larger the shell caliber, the louder the mortar is. Some of the ones you see in this video are 8" shells, so those are pretty incredible when they fire. That is one neat thing about being a pyrotechnician, we get two "bangs" for every one bang the audience gets, one when the mortar fires, and another when the shell explodes. Thanks for the comment!
Thank you so much for this explanation!! I'm from Germany and saw a few fireworks that contained hearts, absolutely loved them but kept wondering how that would be made! Interesting!! I had just assumed they would be rockets but i see why mortars are better for professional shows :o Today I saw a show where they constricted cats and that looked so damn cool in the sky so i had to find out how that works and I'm glad i came across this explanation with examples! what happens to the mortar shells? do they burn up? do they explode into small enough pieces? i read through the comments and found that it is possible to find shell fragments sometimes! they come down in a zone where none of the viewers are allowed to be, only the protected crew. do they have to be round? (to have a precise angle and speed etc probably yes, right?) for example what would a mortar look like that shows up as a star shape in the sky? the outer shell a circle and in the front and back half more filling material and then around the midsection of the ball a star shape arranged with only the tips of the star close to the edge of the shell? and how would one make a mortar that shows up as a round circle that changes colour twice (so three colours in one explosion)? what makes the shrill whistling sound sometimes used? "Great question. The whistling effects are generated by Potassium Benzoate packed into a resonator tube." thanks 👍
Thanks for the kind words! Great questions, let's answer one at a time. What goes up, must come down. The cardboard shell casings just fall down to the ground after the shell explodes, the pieces varying in size. This is one reason we have a "fallout" zone where no one other than the crew is allowed during a show. No, they do not need to be round. Traditional Japanese style shells are round and a majority of what we typically use, but there are also Italian style shells that are cylindrical and can contain a variety of different effects and are a great compliment to round aerial shells during a show. Pattern shells are made by simply laying the stars out in the shell, exactly how you want them to appear in the sky. Burst charge would fill the remaining portion of the shell. A number of different laws of physics contribute to this capability, but the law of conservation of momentum is the main driving force behind the ability to make a simple pattern shell. Color changing stars are made by layering different compositions in appropriate thicknesses as you build the layering of a rolled star. The large shells, which can accommodate larger stars, can have a number of different color changing layers. Thanks for the questions and comments!
Great questions. We only need to clean debris out of the mortars which would prevent a subsequent shell from sitting all the way on the bottom. Black powder fouling is a non-issue. Smokeless powders don’t burn fast enough out in the open to produce sufficient pressure behind the shell. Smokeless powders perform well in confinement which produce a higher pressure environment such as a firearm cartridge.
Michael, that is a great idea, we will think about it for a bit and hopefully put together a great video showing the ins and outs of a big show in the near future. Thanks for your comment!
Can we get the slowMo guys to film one explode from close up. (Not launching into the air but filming off a gantry 10m off the ground) and some bullet proof glass. Thanks.
The cardboard shell casing certainly comes back down after the shell explodes, and this is not unique to locations like Disneyland. Pieces can range from tiny shreds of cardboard to entire hemispheres. This is one of the main reasons we have what is know as a “fallout zone” or “exclusion zone” at professional display, where only the well protected crew is allowed to be during the show.
Hi David, I think you are referring to the lift charge, not the burst charge, let me know if I misunderstood your question. The lift charge firing the shell out of the mortar is fairly violent; however, the hardened paper casing is more than enough to take the hit upon launch. The more common failure mechanism is not from the casing itself, but instead from a poorly sealed time fuse (time fuse is sealed to the shell casing). Any leak point can cause fire to leak into the shell during lift and cause a "flower pot" malfunction. Having said all that, it gets very complicated as you get above 12" shells, additional considerations like stand off distances and shell casing thicknesses become highly relevant in successfully getting the shell out of the mortar.
Very informative. Thank you. Your example looks like it's Japanese or Chinese. Did we inherit our knowledge of artful fireworks from them? Are any American companies doing innovative things with pro fireworks?
Thanks for the kind words, glad you enjoyed the video! Chinese were the first to invent black powder, which fireworks eventually evolved from. Fireworks are manufactured all over the world now and each culture brings a unique style. Yes, our spherical shell is a traditional japanese style shell.
I like those super loud BOOM ones, you know the one that kinda echos, shakes the ground a little bit sounds kinda like a thud. Usually not much of a display except for a little bit of orange. It's usually one of the first fireworks to be shot off, I guess to get people's attention. What are those called ? Thanks.
@Eddini76, those are known as Salutes. A salute isn't much different than a regular star burst shell, except it is filled entirely with flash powder instead of stars and burst charge, everything else being the same. Salutes break too hard to have stars, but sometimes titanium flakes are added, which give the ball of white sparks when a salute explodes. Flash powder burns much more rapidly than standard burst, which gives the loud "report" that you hear.
@@PyroInnovations I live in N.H. sadly they are illegal here. They must be bigger though to be so loud. I also like the ones where the sparks break off into mini firework sparks.
Ignition of stars is very reliable. As mentioned in the video, stars are primed with black powder (more or less) which ignites very easily and seamlessly transitions to the colored composition inside. If the burst charge is too powerful you can get the stars to blow blind as they will not have enough time to reach their ignition temperature before the shell explodes. Great question!
@@pyroblastguy there is not a generic name for a shell that has whistling effects. The name is associated with the effect within the shell itself. In other words, an example of a shell with whistles could be named "Red Peony with Whistling Pistol."
I always wondered how a firework was made to explode in different pattern, shapes, & sizes. Another things what would happen if the firework had a malfunction when it’s already going into the air ....
If the firework "malfunctions" or explodes early, early being defined as some point after leaving the muzzle of the mortar to prior to reaching its apogee, you simply get what's called a "low break." This is simply the shell exploding closer to the ground, which is one of the many reasons we have a "fallout zone" or "exclusion zone" during a professional display, so that the only thing that happens is the audience goes, "ooooooohhh," and the show goes on.
Machines do most of the wrapping these days and the insides of a shell do not look like a Christmas bauble. This is a rather basic description and really doesn't get across what shell construction is like nor how stars are made.
Thanks for the comment! But…Incorrect. While certain manufacturers utilize pasting machines, this is definitely not the case for all. There are many countries and cultures that still paste shells by hand. Hand pasting can yield superior consistency and a more even break when done by experienced professionals. Take the Japanese for example, they are true masters of the art. Color was obviously added for better clarity and so that non-pyro audiences could clearly distinguish between the different areas of the shell as we went through the explanation. Basic description? That’s exactly what it is supposed to be, “How Fireworks Work,” not instructions on how to build a shell…LOL Thanks for your comment!
For the shells that have designs like the happy face, is there a way to know which way everything will fly out once it explodes, that way it wouldn't be sideways from the crowds perspective?
Only for one of two dimensions. You could theoretically configure it as a "rocket" by lowering the center of pressure down below the shell (think a stick like a sky rocket), but that would only control one dimension. It would still be able to rotate around its center axis. So long story short, no, which is why when ever we do a happy face or other pattern shell look, we send multiple shells up so that statistically one or more will likely break with the proper orientation to the audience. Great question!
For the most part no and for this reason I've always looked at this effect as kind of gimmicky. At the end of the day though if people enjoy the effect theres no harm in it.
This is such a great educational video - so clear, nothing overdramatised and simply explained. Thank you for teaching me something I had assumed completely incorrectly all these years!
I have a question. Thanks for the great explanation but there are some affects at the very end of the explosion which cause tge stars to travel or move if you get what i mean. How is this done?
Levi, what you are describing could either be an insert or flying fish fuse. An insert is exactly that, a small stand alone device that is inserted into the shell. Think of a small cardboard tube with composition in it, which ignites after the shell breaks. The insert could be a whistle, tourbillion, or a number of other effects. Flying fish fuse is a special type of fuse that gives a self propelling spreading in random directions spark effect. So for fish fuse, imagine a bunch of tiny pieces of fuse inside the shell that are designed to produce that effect. Thanks for the comments and question!
I miss the years doing shows with Bartolotta Fireworks. Back then ... late 70 - mid 80's shot our shows by hand .. electrical systems hadn't been perfected yet.
Farthest I travelled was N. Tonawanda maybe S Tonawanda NY. I was past 16 because I could drive. I remember digging in the mortars, back then they were still steel, and man what a bitch we shot from an old landfill. I swear they only had put like 6" of topsoil ... I remember being behind the Summerfest Mainstage and George Thorogood was the headlining act. He was supposed to do a couple encore's and then the Stars Spangled Banner for his final song. The fireworks were just a succession of salutes that were to be played in time with the music. I remember watching them feverishly loading salute after salute after salute and trying to keep time with the music using a flare ... While I left for the military at 18. I was given the honor to shoot one show for my dad, RIP pop, I tell ya the fun of pulling the cap off the match touching the end .... and watching it burn slowly and then when it hit the paper the whump of it going up. Or .... someone yells ... pick up the pace and ya touched it at the paper .... and the shell was gone before you could actually look down. Ahh the fun. I remember Bartolotta's early years in trailers behind the back barns at the chicken farm. Out of the family I really only remember Tuffie and Jeanie. Couple of years ago saw Jeanie and pretty sure it was mom bartolotta out in Palmyra at a stand there. Oh by the way .... where did all those ground set pieces go. Seems like the last time I saw show that had ground pieces was at the shows in Genesee Depot's park. Ah the memories.
Please make some videos on making small shells like these and instruments and ingredients used in a shell. And i really liked your videos Thanks for sharing such beautiful information ❤👍
Amazing explanation, just what I was wondering to know. But until now I still am intrigued on how do they made a cubic form on Disney Fireworks some times, that must be a little more tricky to do because of the circular explosion... 🤔 Or is it simple to do?! Ps. Once i saw this open model you used to show in the video, I imagined how cool it would be if someone film the open model exploding on a SuperSlow camera. It would be amazing. 🙂
Luigi, thanks for your kind words and comment. A cube can be made in the exact same way as the other pattern shells, maybe a bit more tricky in arranging them and keeping them in place, but ultimately the same physical principles apply. Don't think of it as a "circular" explosion, think of it as a "symmetrical" or "uniform" explosion due to Pascal's law which describes how pressure is equal in all directions within the confined space. Someone actually did that exact experiment a couple years back, can't remember where we saw it, but they basically glued a half built shell to a piece of ploycarbonate, and watched it burn and explode from the time it was ignited. Although very cool and able to provide a little insight, there were some flaws in their setup that would prevent a very accurate representation, especially since the glue would not hold with the same strength that a fully built shell would, causing leakage, lower pressures, and premature failure. Thanks again for your comment!
Great video! Much better than many other explanations of fireworks online. I really like that you don’t over simply and get into the details. Making fireworks is very impressive especially at the scale your doing it. Thanks for sharing!
Great Question! The answer is, very carefully. :) Different shell builders have different techniques, especially when it comes to larger shells, and when you get to a certain size, say above 24" diameter, they are no longer two halves that are put together, it is a different construction process all together.
As Pyro Innovations says, 'very carefully' but it often involves a layer of fine tissue paper on each half, to hold things in place for just long enough to close the shell. The contents of each half are usually pretty firmly packed anyway and the tissue is not substantial enough to affect the ignition or function of the burst charge or stars/effects.
Great question! If not pasted properly or burst charge is not fast enough, yes, but if pasted properly and the correct amount of burst it will be unnoticeable. Some shells also have a boost within the burst consisting of a small amount of flash powder or whistle mix (which burns very fast). Thanks for the comment!
Waited years for a video like this - thank you. Is black powder simply a very refined version of gunpowder? Sulphur, charcoal, potassium nitrate, but calibrated perfectly?
Glad you enjoyed the video. Gunpowder is really just a generic term. When guns were first invented, gunpowder and black powder were one in the same. Today however, nitrocellulose based "smokeless" powder is what is used in modern guns, so in that context gunpowder means something entirely different and is unrelated to black powder. Thanks for your question and comment!
@@PyroInnovations: Thank you! Have just seen a fireworks presentation video and learned about nitrocellulose and its accidental discovery. 🙂 Have learned lots today. Thanks again. 👍
Not too tough to do on the side actually. In normal times, when there are more shows and the aerial display companies need more assistance, keep an eye out for trainings. This is NOT the same as getting your pyro license. I attended a one day training advertised on Facebook run by one of the large companies. It was half a day of classroom training (mostly safety related) and a half day of hands-on setting up different types of shells out in the desert and firing them. Since then, I’ve probably done a dozen or so shows in 2 years fit 3 different companies. The time commitment fit a show is fairly low, usually 1 or 2 days. It’s tough work out in the elements and the pay is usually pretty low, but it’s a lot of fun. There is a federal background check done, so keep that in mind as well. Also your wife will be pissed that you never see 4th of July or NYE fireworks with her. 🙃
Great question. The shell casing is actually very strong and can handle the forces from the lift charge. In larger shells, additional considerations have to be taken into account as the lift forces begin to become more troublesome. Shell casing thickness, stand-off from the bottom of the mortar (and the lift), time fuse sealing, are just a few of the additional considerations that are taken into account for much larger shells.
@@PyroInnovations Wow, that's a lot I didn't even think about! Not that I would as I'm just a layman, but this is fascinating stuff. I assume professional display companies buy their stock ready made? I'd love to build my own one day to experiment but legally speaking it would have to be absolutely tiny as hell so I don't have MI5 knocking at my door 👀 I should probably work on getting a sugar-rocket to fly first...
Good day! can i know why lift charge is confined in plastic? Is this for additional protection to prevent the Lift charge from spilling when the lift cup is torn? Thank you very much
What I really wanna know is how they compress those effect balls and what material they have. We all know the lift is black powder and hard salute breaks are titanium and potassium perchlorate+aluminium powder(flash) 😉
There are a number of different methods of manufacturing stars, the three main ones are rolled, pressed, and cut. Compositions for each effect type vary quite a bit. We recommend getting involved with a local pyrotechnics club if you are interested in learning more.
@@PyroInnovations Its not my "calling" so to speak but I'm a little bit of a fanatic still about having the best bang for buck and knowing what I'm dealing with when using fireworks :) So do the professional display shells ever contain flash as the break charge or are those shells mostly only black powder explosions? Anyways thanks for the reply!
Burst charge used in shells isn't quite black powder, but somewhat similar. It produces a larger quantity of hot gas which allows it to overpressure the shell appropriately. Shells can have the burst charge "spiked" with a small amount of faster burning comp, but it is rarely flash powder. The most common we have seen used is whistle mix as it burns faster than burst charge, but not as fast or as sensitive as flash.
@@PyroInnovations Yeah I was thinking theres no way BP could be "that" powerful. Ive heard some people use kno3 instead of KClO4 for bangers so I wouldve guessed its nitrate if not powder or chlorate :)
Brilliant! I'll have to show my son this video tomorrow after he asked me how fireworks work at tonight's public display. Now I know how they work too! Thank you
Hi Zion, great question. The answer is, it depends on what state you are in. Every state has different requirements, here is a good example of what is required in CA to become a licensed pyrotechnician: pyroinnovations.com/pyrotechnics_license_requirements.html
Im surprised the shell can handle the lift charge without destroying it. And the pressure in the shell must be substantially greater in order for it to explode when ignited.
The shell casing, especially after being pasted with the many layers of paper, is actually quite strong. If a shell fails in the mortar (i.e. explodes) when the lift charge fires, it’s usually because of improperly or inadequately sealed time fuse. This of course is a simple spherical shell example, as things get more complicated with multibreak. Things start to get real interesting with larger shells (greater than 12”), as they begin to require a stand-off distance from the lift charge due to the substantial size of the lift charge as you go up in shell size. In the large shell case, you could start destroying the shells in the mortar with the power of the lift charge. To make it even more complicated, the thickness of the shell casing increases as well as you go up in shell diameter, so it is a always a balancing act to ensure the shell functions as designed.
@@donamills Actually, the larger the shell, the higher it needs to go before functioning. The general rule of thumb is 100’ per inch diameter of shell. So for example, a 16” shell will reach approximately 1,600’ before exploding. Roughly half that is the break diameter, meaning that same 16” will likely break close to 800’ across in the sky. They get pretty heavy as they go up in size, a 16” shell will typically weigh a bit over 50 lbs.
@@PyroInnovations wow, that's super crazy. It's like lobbing a 50lb bag of salt a quarter-mile up in the air. Instead of oohs and aahs, it should be "holyshit!"
i am now at my kitchen table making one from his detailed articulate explanation of how it goes boom pop bang i much rather id he showed us a 60 inch shell split in half and held it like that
Can someone teach me how to make a little one in my house? I really want to make one for our traditional ceremony which is called Chaharshanbe soori which is in the next few months
I have a question how do I become a 🧨 pyro ❓I been a huge fan of fireworks all my life. I always bought fireworks every year.Didn’t know if you want big fireworks I 👀 it cost more.Right now how can I become a pyro?
You’re very welcome! Once you turn 18 and if you reside on the west coast of the USA, you can apply to join our team here: www.pyroinnovations.com/becomecrew2.html
Very well done. I've always wondered how these things worked. About how high does that 8" shell go before exploding? How much does a single 8" shell cost (on average, I realize they can vary)? How much debris falls back to the ground? The shell casing looks very thick.
Thanks for the kind words! Standard rule of thumb for height is 100’ per inch of shell diameter, so for an 8” shell it would be roughly 800 feet. Check out this video, it covers some of that sort of info in more detail: ua-cam.com/video/C7lCoRVoxLM/v-deo.html. Cost can vary dramatically, best to look up price lists online, there are a number of vendors who publish them on the web. Yes, everything that goes up, comes back down. The entity of the cardboard shell casing is the bulk of what comes down, it can come down in small fragments to entire hemispheres depending on how it broke. This is why we have a “fallout zone” or exclusion zone when it comes to professional fireworks displays, where only the well protected crew is allowed. Thanks for the comments, great questions!
In the video, we are specifically referring to a public display being shot by professional pyrotechnicians, which clearly was not the case in the example you gave. Mortars are very safe when used and secured properly, and shot a safe distance from the audience.
Strontium salts, not radioactive strontium isotopes…LOL. Keep in mind, elemental Sodium explodes when it hits water, and elemental Chlorine is toxic, but when molecularly combined into sodium chloride, it’s known as table salt… 😉
So i'm wondering how the squirrely lights are done? After the explosion a small number of lights appear and they wiggle around on their way out from the main explosion
There are a couple different effects you may be referring to, but I believe what you are describing is what we call fish fuse. The other effect you may be describing could be a tourbillion.
in another video you said the height of detonation is 100 ft per 1 inch firework thickness so in this firework does the timefuse need to be 8 inch long to achieve the 800 ft detonation? or are there different timefuse burns?? thank you for all the information you provide..
Great question! Short answer is no, the 8” shell used in the example would not have an 8” time fuse. The time fuse shown in the example is exaggerated and would not be that long in a real shell of that size. The time fuse would actually be much shorter, and terminate in a passfire tube that would have something like black match in it, which would flash very fast (like quick match) to the end of the passfire tube in the center of the shell. Great question!
I think this was a great and informative video! I enjoy learning about how things work and have been watching Workers assembling shells. Their work is so intricate!
Wow what an interesting video (and channel). Ok for my question, does the lift charge have to be greater than the time the black powder filled straw takes to burn so the shell detonates at the correct time. In other words, do you want the shell to detonate at the epogy, or when the shell is still climbing. I gather you don;t wat the shell to detonate when it's comming down, or worse at ground level.
Great question, and the answer is yes, you want the shell to explode at apogee. This yields the desired look, height, and doesn’t lead to stars hitting the ground, which would be a fire hazard. Professionally made shells rarely have any issues with burst height, unless they were not loaded all the way down in the mortar like they were supposed to be.
I don’t have any questions, but I do want to thank you, as one individual among many, who have positively impacted my life: mine, my wife, our families, friends and loved ones over the year. Thanks!
Thanks for the kind words!
I was a nuclear weapons specialist in the Air Force. Thank you for the video. Always wondered how the little guys worked.
Thanks for your service!
Thank you, there is so much crap on UA-cam, but this is the kind of stuff that keeps me going. A great video with industry information presented in an understandable manner by a guy that is obviously at the top of his profession. And let's not forget, no annoying music, thank you for that as well.
@Steb Stebanesier, thanks for the kind words, much appreciated.
Right. I hate annoying music
Spot on with this comment. Couldn’t agree more
I couldn't have said this better. Completely agree
Thanks for sharing, explained very clearly and simply.
Thanks for the kind words, glad you enjoyed it!
Thank you something I wish there was more of these days on UA-cam and that's videos that are informative, not dumbed down, nor highbrow either that are presented by someone who knows what they are talking about!
And not only that but then someone that is willing to take the time to share some of what he knows without music that makes you want to dig your ears out lol
So thank you on many fronts!
I have always thought that I would love to do what you'll do for living and after hearing all that you just explained I think I wood be quite capable of and enjoy doing so..... now if only I'd been born into one of the families in my part of the world that seem to control the larger end of the market.... Ohh well I can dream 👍
Keep up the amazing work! Cheers
Thanks for all the kind words! Glad you enjoyed the video!
Watching this as the 4th of July firework show across the street keeps me awake! “What’s going on out there?” 😂🎉
Glad we could both entertain and inform! Happy 4th!
Nice commentary...thanks
Our pleasure!
Great to hear about all this. I was really amazed by the fact that pro fireworks are actually mortar shells instead of rockets.
Thanks for your comments, glad we could help!
Theyre safer because there isnt a big rocket hauling at anyone sideways if things go wrong. Mortars throw everything up and there is no big stick to drop from the sky afterwards either :)
I noticed that in this video the launch charge was very loud but at a professional fireworks show it sounds very subdued. Sometimes you can hardly hear it and I've always wondered how they are launched into the air and why it sounded that way. It sounds like a big puff of air and my guess is it's not very loud because it's down in a tube.
It sounds subdued at a professional display (if you can hear it at all) because the audience is a good distance away from where the shells are being fired, a safety requirement outlined by federal and local laws. The mortars are very loud, it is literally like a cannon firing a cannon ball. The pyro crew is much closer, which is where the footage you are referencing was shot from. The larger the shell caliber, the louder the mortar is. Some of the ones you see in this video are 8" shells, so those are pretty incredible when they fire. That is one neat thing about being a pyrotechnician, we get two "bangs" for every one bang the audience gets, one when the mortar fires, and another when the shell explodes. Thanks for the comment!
@@PyroInnovations Very interesting, thanks for replying 👍
Thank you so much for this explanation!! I'm from Germany and saw a few fireworks that contained hearts, absolutely loved them but kept wondering how that would be made! Interesting!! I had just assumed they would be rockets but i see why mortars are better for professional shows :o
Today I saw a show where they constricted cats and that looked so damn cool in the sky so i had to find out how that works and I'm glad i came across this explanation with examples!
what happens to the mortar shells? do they burn up? do they explode into small enough pieces?
i read through the comments and found that it is possible to find shell fragments sometimes! they come down in a zone where none of the viewers are allowed to be, only the protected crew.
do they have to be round? (to have a precise angle and speed etc probably yes, right?)
for example what would a mortar look like that shows up as a star shape in the sky? the outer shell a circle and in the front and back half more filling material and then around the midsection of the ball a star shape arranged with only the tips of the star close to the edge of the shell?
and how would one make a mortar that shows up as a round circle that changes colour twice (so three colours in one explosion)?
what makes the shrill whistling sound sometimes used?
"Great question. The whistling effects are generated by Potassium Benzoate packed into a resonator tube." thanks 👍
Thanks for the kind words! Great questions, let's answer one at a time. What goes up, must come down. The cardboard shell casings just fall down to the ground after the shell explodes, the pieces varying in size. This is one reason we have a "fallout" zone where no one other than the crew is allowed during a show.
No, they do not need to be round. Traditional Japanese style shells are round and a majority of what we typically use, but there are also Italian style shells that are cylindrical and can contain a variety of different effects and are a great compliment to round aerial shells during a show.
Pattern shells are made by simply laying the stars out in the shell, exactly how you want them to appear in the sky. Burst charge would fill the remaining portion of the shell. A number of different laws of physics contribute to this capability, but the law of conservation of momentum is the main driving force behind the ability to make a simple pattern shell.
Color changing stars are made by layering different compositions in appropriate thicknesses as you build the layering of a rolled star. The large shells, which can accommodate larger stars, can have a number of different color changing layers.
Thanks for the questions and comments!
Underrated video
Thanks for the kind words!
Do you have to clean your mortars after each display to reduce black powder fowling? Do you ever use smokeless powder or pyrodex as a propellent?
Great questions. We only need to clean debris out of the mortars which would prevent a subsequent shell from sitting all the way on the bottom. Black powder fouling is a non-issue. Smokeless powders don’t burn fast enough out in the open to produce sufficient pressure behind the shell. Smokeless powders perform well in confinement which produce a higher pressure environment such as a firearm cartridge.
The shell shock... Nice.. Large. Like a s550 luancer
Hi sir,
Please share a video on star roller, how to make a star roller, and what type of motor should i use for it???
Made my first 3 and 4 inch shells last year. Some fails and some were good
At first I thought he was holding a huge onion.
Anything can be done, anything can be anything if you believe it hard enough
It is an onion.... Of explosives.
You think that’s something, you should see the hamburger it goes on! 😯
😂😂😂
I thought the same thing 😂😂😂
Where can I buy those?
can you do a video of how they ignite and time big shows
Michael, that is a great idea, we will think about it for a bit and hopefully put together a great video showing the ins and outs of a big show in the near future. Thanks for your comment!
Can we get the slowMo guys to film one explode from close up. (Not launching into the air but filming off a gantry 10m off the ground) and some bullet proof glass. Thanks.
Yes! We actually reached out to them for this very thing a number of years ago, but no response. :(
Amazing! I was today year old to find out.
Glad we could help!
In a display like Disneyland’s for instance, do remnants of the cardboard shell fall onto neighborhoods, or are they completely consumed by the blast?
The cardboard shell casing certainly comes back down after the shell explodes, and this is not unique to locations like Disneyland. Pieces can range from tiny shreds of cardboard to entire hemispheres. This is one of the main reasons we have what is know as a “fallout zone” or “exclusion zone” at professional display, where only the well protected crew is allowed to be during the show.
How does the burst charge not damage the load/shell on the way out of the tube? The explosion of the charge always sounds pretty violent.
Hi David, I think you are referring to the lift charge, not the burst charge, let me know if I misunderstood your question. The lift charge firing the shell out of the mortar is fairly violent; however, the hardened paper casing is more than enough to take the hit upon launch. The more common failure mechanism is not from the casing itself, but instead from a poorly sealed time fuse (time fuse is sealed to the shell casing). Any leak point can cause fire to leak into the shell during lift and cause a "flower pot" malfunction. Having said all that, it gets very complicated as you get above 12" shells, additional considerations like stand off distances and shell casing thicknesses become highly relevant in successfully getting the shell out of the mortar.
@@PyroInnovations Thanks! yes I meant lift charge.
Very informative. Thank you. Your example looks like it's Japanese or Chinese. Did we inherit our knowledge of artful fireworks from them? Are any American companies doing innovative things with pro fireworks?
Thanks for the kind words, glad you enjoyed the video! Chinese were the first to invent black powder, which fireworks eventually evolved from. Fireworks are manufactured all over the world now and each culture brings a unique style. Yes, our spherical shell is a traditional japanese style shell.
there aren't many american firework companies but devices like the whistle rocket and strobe rocket were invented in America
Not much unlike 19th century cannonfire. Especially the smoothbore shells looked very much like this.
I like those super loud BOOM ones, you know the one that kinda echos, shakes the ground a little bit sounds kinda like a thud. Usually not much of a display except for a little bit of orange. It's usually one of the first fireworks to be shot off, I guess to get people's attention. What are those called ? Thanks.
It almost sounds like when the shuttle breaks the sound barrier.
I don't know if this helps but in another comment he said salute shells were the loudest.
@Eddini76, those are known as Salutes. A salute isn't much different than a regular star burst shell, except it is filled entirely with flash powder instead of stars and burst charge, everything else being the same. Salutes break too hard to have stars, but sometimes titanium flakes are added, which give the ball of white sparks when a salute explodes. Flash powder burns much more rapidly than standard burst, which gives the loud "report" that you hear.
@@PyroInnovations I live in N.H. sadly they are illegal here. They must be bigger though to be so loud. I also like the ones where the sparks break off into mini firework sparks.
The thumbnail made it look like dude was missing fingers.
👏
Awesome! Now I have a clue.
I also wonder how reliable ignition of all stars is.
Ignition of stars is very reliable. As mentioned in the video, stars are primed with black powder (more or less) which ignites very easily and seamlessly transitions to the colored composition inside. If the burst charge is too powerful you can get the stars to blow blind as they will not have enough time to reach their ignition temperature before the shell explodes. Great question!
I had crewed maybe 6 shows before I found my first unignited star.
What are the shells with whistling called?
Great question. The whistling effects are generated by Potassium Benzoate packed into a resonator tube.
Pyro Innovations That’s amazing! The shells with the whistles, what is the name of those?
@@pyroblastguy there is not a generic name for a shell that has whistling effects. The name is associated with the effect within the shell itself. In other words, an example of a shell with whistles could be named "Red Peony with Whistling Pistol."
Pyro Innovations Alright. Really cool! I could learn about this stuff all day haha.
Consumer is wistling buster
I always wondered how a firework was made to explode in different pattern, shapes, & sizes. Another things what would happen if the firework had a malfunction when it’s already going into the air ....
If the firework "malfunctions" or explodes early, early being defined as some point after leaving the muzzle of the mortar to prior to reaching its apogee, you simply get what's called a "low break." This is simply the shell exploding closer to the ground, which is one of the many reasons we have a "fallout zone" or "exclusion zone" during a professional display, so that the only thing that happens is the audience goes, "ooooooohhh," and the show goes on.
Looks like an onion an behaves as such to. Layers after layers. 500 kg BOOM is AWESOME
Machines do most of the wrapping these days and the insides of a shell do not look like a Christmas bauble. This is a rather basic description and really doesn't get across what shell construction is like nor how stars are made.
Thanks for the comment! But…Incorrect. While certain manufacturers utilize pasting machines, this is definitely not the case for all. There are many countries and cultures that still paste shells by hand. Hand pasting can yield superior consistency and a more even break when done by experienced professionals. Take the Japanese for example, they are true masters of the art. Color was obviously added for better clarity and so that non-pyro audiences could clearly distinguish between the different areas of the shell as we went through the explanation. Basic description? That’s exactly what it is supposed to be, “How Fireworks Work,” not instructions on how to build a shell…LOL Thanks for your comment!
no
So how do babies get their hands on them and disturb my sleep I heard from firefighters that they can kill you 😢
For the shells that have designs like the happy face, is there a way to know which way everything will fly out once it explodes, that way it wouldn't be sideways from the crowds perspective?
Only for one of two dimensions. You could theoretically configure it as a "rocket" by lowering the center of pressure down below the shell (think a stick like a sky rocket), but that would only control one dimension. It would still be able to rotate around its center axis. So long story short, no, which is why when ever we do a happy face or other pattern shell look, we send multiple shells up so that statistically one or more will likely break with the proper orientation to the audience. Great question!
I've seen pattern shells blow every possible angle it just depends which way it tumbles before reaching apogee and the Burst charge ignites
You can build shells Like parosol shells, that is in the right direction
The shell spins in the air so no not really
For the most part no and for this reason I've always looked at this effect as kind of gimmicky. At the end of the day though if people enjoy the effect theres no harm in it.
This is such a great educational video - so clear, nothing overdramatised and simply explained. Thank you for teaching me something I had assumed completely incorrectly all these years!
@TheEnglishRedneck45 Thanks for the kind words, glad you enjoyed it!
I have a question.
Thanks for the great explanation but there are some affects at the very end of the explosion which cause tge stars to travel or move if you get what i mean.
How is this done?
Levi, what you are describing could either be an insert or flying fish fuse. An insert is exactly that, a small stand alone device that is inserted into the shell. Think of a small cardboard tube with composition in it, which ignites after the shell breaks. The insert could be a whistle, tourbillion, or a number of other effects. Flying fish fuse is a special type of fuse that gives a self propelling spreading in random directions spark effect. So for fish fuse, imagine a bunch of tiny pieces of fuse inside the shell that are designed to produce that effect. Thanks for the comments and question!
Here's some more info/visuals on what Mike is describing: www.skylighter.com/blogs/how-to-make-fireworks/stars-shell-inserts
I miss the years doing shows with Bartolotta Fireworks.
Back then ... late 70 - mid 80's shot our shows by hand .. electrical systems hadn't been perfected yet.
Farthest I travelled was N. Tonawanda maybe S Tonawanda NY. I was past 16 because I could drive. I remember digging in the mortars, back then they were still steel, and man what a bitch we shot from an old landfill. I swear they only had put like 6" of topsoil ...
I remember being behind the Summerfest Mainstage and George Thorogood was the headlining act. He was supposed to do a couple encore's and then the Stars Spangled Banner for his final song. The fireworks were just a succession of salutes that were to be played in time with the music. I remember watching them feverishly loading salute after salute after salute and trying to keep time with the music using a flare ...
While I left for the military at 18. I was given the honor to shoot one show for my dad, RIP pop, I tell ya the fun of pulling the cap off the match touching the end .... and watching it burn slowly and then when it hit the paper the whump of it going up. Or .... someone yells ... pick up the pace and ya touched it at the paper .... and the shell was gone before you could actually look down.
Ahh the fun. I remember Bartolotta's early years in trailers behind the back barns at the chicken farm. Out of the family I really only remember Tuffie and Jeanie. Couple of years ago saw Jeanie and pretty sure it was mom bartolotta out in Palmyra at a stand there.
Oh by the way .... where did all those ground set pieces go. Seems like the last time I saw show that had ground pieces was at the shows in Genesee Depot's park.
Ah the memories.
Please make some videos on making small shells like these and instruments and ingredients used in a shell.
And i really liked your videos
Thanks for sharing such beautiful information ❤👍
Thank's man voor the clear explenation. What is de ration between de size of the shell and the blackpowder undernead the shell?
Amazing explanation, just what I was wondering to know. But until now I still am intrigued on how do they made a cubic form on Disney Fireworks some times, that must be a little more tricky to do because of the circular explosion... 🤔 Or is it simple to do?!
Ps. Once i saw this open model you used to show in the video, I imagined how cool it would be if someone film the open model exploding on a SuperSlow camera. It would be amazing. 🙂
Luigi, thanks for your kind words and comment. A cube can be made in the exact same way as the other pattern shells, maybe a bit more tricky in arranging them and keeping them in place, but ultimately the same physical principles apply. Don't think of it as a "circular" explosion, think of it as a "symmetrical" or "uniform" explosion due to Pascal's law which describes how pressure is equal in all directions within the confined space.
Someone actually did that exact experiment a couple years back, can't remember where we saw it, but they basically glued a half built shell to a piece of ploycarbonate, and watched it burn and explode from the time it was ignited. Although very cool and able to provide a little insight, there were some flaws in their setup that would prevent a very accurate representation, especially since the glue would not hold with the same strength that a fully built shell would, causing leakage, lower pressures, and premature failure. Thanks again for your comment!
@@PyroInnovations thank you very much for the reply and the explanation. I think I got it. 🙂 I wish you health and sucess. Thanks
@Luigi, no problem, same to you!
I’ve always wondered how they make it to where it makes designed in the air like how do they know it gonna do that😭😭
This makes me really appreciate the work that Disney puts into their firework shows even more
@Kiwi Kiwi, you might appreciate this video then: ua-cam.com/video/chWpijWjQCo/v-deo.html
@kiwi kiwi, our pleasure.
@@PyroInnovations He definitely changed how the public sees pyro displays forever!
Great video! Much better than many other explanations of fireworks online. I really like that you don’t over simply and get into the details. Making fireworks is very impressive especially at the scale your doing it. Thanks for sharing!
We appreciate the kind words!
This was so good, I would watch this fellow teach us about anything at all. Peanut butter? Snakes? World War 1? I'm in.
Peanut butter it is. 😜
How are the two halves brought together without the contents spilling out?
Great Question! The answer is, very carefully. :) Different shell builders have different techniques, especially when it comes to larger shells, and when you get to a certain size, say above 24" diameter, they are no longer two halves that are put together, it is a different construction process all together.
As Pyro Innovations says, 'very carefully' but it often involves a layer of fine tissue paper on each half, to hold things in place for just long enough to close the shell. The contents of each half are usually pretty firmly packed anyway and the tissue is not substantial enough to affect the ignition or function of the burst charge or stars/effects.
Does the shell split down the center where the two halves are fastened together if not what stops this being a weak point
Great question! If not pasted properly or burst charge is not fast enough, yes, but if pasted properly and the correct amount of burst it will be unnoticeable. Some shells also have a boost within the burst consisting of a small amount of flash powder or whistle mix (which burns very fast). Thanks for the comment!
Thanks
Give me a good deal of information to my desire of know how it works.
Glad we could help!
Excellent video. Great explanation. I learned something.
Thanks! Glad we could be of service!
Waited years for a video like this - thank you. Is black powder simply a very refined version of gunpowder? Sulphur, charcoal, potassium nitrate, but calibrated perfectly?
Glad you enjoyed the video. Gunpowder is really just a generic term. When guns were first invented, gunpowder and black powder were one in the same. Today however, nitrocellulose based "smokeless" powder is what is used in modern guns, so in that context gunpowder means something entirely different and is unrelated to black powder. Thanks for your question and comment!
@@PyroInnovations: Thank you! Have just seen a fireworks presentation video and learned about nitrocellulose and its accidental discovery. 🙂 Have learned lots today. Thanks again. 👍
Well explained! Consider me your newest subscriber!
😃 Thanks!
That was a really good educational video. I learned alot.
Glad it was helpful!
So friggin kewl. I should have chosen that as a career path.
Not too tough to do on the side actually. In normal times, when there are more shows and the aerial display companies need more assistance, keep an eye out for trainings. This is NOT the same as getting your pyro license. I attended a one day training advertised on Facebook run by one of the large companies. It was half a day of classroom training (mostly safety related) and a half day of hands-on setting up different types of shells out in the desert and firing them. Since then, I’ve probably done a dozen or so shows in 2 years fit 3 different companies. The time commitment fit a show is fairly low, usually 1 or 2 days. It’s tough work out in the elements and the pay is usually pretty low, but it’s a lot of fun. There is a federal background check done, so keep that in mind as well. Also your wife will be pissed that you never see 4th of July or NYE fireworks with her. 🙃
The video i didn't know i needed
Thankyou for defining internal structure of it. I was wondering since childhood about effects of it.
Great! Glad we were able to provide some insight. Thanks for your comment!
Mp
that was so worth the view
No waste of time. Just good info. Thanks.
Thanks for the kind words!
And to top it off, it’s ashes where it came from people’s bodies where it was cremated where it goes in the shell.
i really like your hair.
How does the black powder charge not blow the top of the shell off?
Great question. The shell casing is actually very strong and can handle the forces from the lift charge. In larger shells, additional considerations have to be taken into account as the lift forces begin to become more troublesome. Shell casing thickness, stand-off from the bottom of the mortar (and the lift), time fuse sealing, are just a few of the additional considerations that are taken into account for much larger shells.
@@PyroInnovations Wow, that's a lot I didn't even think about! Not that I would as I'm just a layman, but this is fascinating stuff.
I assume professional display companies buy their stock ready made? I'd love to build my own one day to experiment but legally speaking it would have to be absolutely tiny as hell so I don't have MI5 knocking at my door 👀 I should probably work on getting a sugar-rocket to fly first...
Will you ever do a "yonshakedama"?
One can only dream. 😄
Good day! can i know why lift charge is confined in plastic?
Is this for additional protection to prevent the Lift charge from spilling when the lift cup is torn? Thank you very much
this should be on UA-cam front page
Best comment ever! 👍👍👍
What I really wanna know is how they compress those effect balls and what material they have. We all know the lift is black powder and hard salute breaks are titanium and potassium perchlorate+aluminium powder(flash) 😉
There are a number of different methods of manufacturing stars, the three main ones are rolled, pressed, and cut. Compositions for each effect type vary quite a bit. We recommend getting involved with a local pyrotechnics club if you are interested in learning more.
@@PyroInnovations Its not my "calling" so to speak but I'm a little bit of a fanatic still about having the best bang for buck and knowing what I'm dealing with when using fireworks :) So do the professional display shells ever contain flash as the break charge or are those shells mostly only black powder explosions? Anyways thanks for the reply!
Burst charge used in shells isn't quite black powder, but somewhat similar. It produces a larger quantity of hot gas which allows it to overpressure the shell appropriately. Shells can have the burst charge "spiked" with a small amount of faster burning comp, but it is rarely flash powder. The most common we have seen used is whistle mix as it burns faster than burst charge, but not as fast or as sensitive as flash.
@@PyroInnovations Yeah I was thinking theres no way BP could be "that" powerful.
Ive heard some people use kno3 instead of KClO4 for bangers so I wouldve guessed its nitrate if not powder or chlorate :)
One of the best YT videos I’ve seen in a while. Thank you!
Thanks for the kind words Kevin, glad you enjoyed it!
Kaboom.
Brilliant! I'll have to show my son this video tomorrow after he asked me how fireworks work at tonight's public display. Now I know how they work too! Thank you
Thanks for the kind words. We hope your son enjoys it too!
How long does it take to become a pyro
Hi Zion, great question. The answer is, it depends on what state you are in. Every state has different requirements, here is a good example of what is required in CA to become a licensed pyrotechnician: pyroinnovations.com/pyrotechnics_license_requirements.html
What happens to the outer shell casing? Does it burn up?
The bursting of the shell causes the paper casing to shred into small pieces, it does not burn up.
Not always. Sometimes you get big chunks coming back down. That's why we need a fallout zone
Thank you. 🎈
Im surprised the shell can handle the lift charge without destroying it.
And the pressure in the shell must be substantially greater in order for it to explode when ignited.
The shell casing, especially after being pasted with the many layers of paper, is actually quite strong. If a shell fails in the mortar (i.e. explodes) when the lift charge fires, it’s usually because of improperly or inadequately sealed time fuse. This of course is a simple spherical shell example, as things get more complicated with multibreak. Things start to get real interesting with larger shells (greater than 12”), as they begin to require a stand-off distance from the lift charge due to the substantial size of the lift charge as you go up in shell size. In the large shell case, you could start destroying the shells in the mortar with the power of the lift charge. To make it even more complicated, the thickness of the shell casing increases as well as you go up in shell diameter, so it is a always a balancing act to ensure the shell functions as designed.
@@PyroInnovations Thats crazy. So I take it the larger the shell the less height you get out of them? BTW 12" is a huge shell. And what do they weigh?
@@donamills Actually, the larger the shell, the higher it needs to go before functioning. The general rule of thumb is 100’ per inch diameter of shell. So for example, a 16” shell will reach approximately 1,600’ before exploding. Roughly half that is the break diameter, meaning that same 16” will likely break close to 800’ across in the sky. They get pretty heavy as they go up in size, a 16” shell will typically weigh a bit over 50 lbs.
@@PyroInnovations wow, that's super crazy. It's like lobbing a 50lb bag of salt a quarter-mile up in the air. Instead of oohs and aahs, it should be "holyshit!"
i am now at my kitchen table making one from his detailed articulate explanation of how it goes boom pop bang i much rather id he showed us a 60 inch shell split in half and held it like that
Very informative thanks!
You’re very welcome, glad you enjoyed it!
Can someone teach me how to make a little one in my house? I really want to make one for our traditional ceremony which is called Chaharshanbe soori which is in the next few months
Can I use Nano3 in blackpowder. Cause other materials are not existed here.
Cool👍
Very interesting, thankyou
Glad you enjoyed it!
I have a question how do I become a 🧨 pyro ❓I been a huge fan of fireworks all my life. I always bought fireworks every year.Didn’t know if you want big fireworks I 👀 it cost more.Right now how can I become a pyro?
If you reside in CA, WA, or ID, you can apply to join our crews here: pyroinnovations.com/becomecrew2.html
How about the one Gandalf use
It's good to see a professional video on how fireworks work, by someone who is in the industry.
Glad you enjoyed it!
Im 14 years old and i always wanted to become a pyrotechnic. Thank you for this informational video!!!
You’re very welcome! Once you turn 18 and if you reside on the west coast of the USA, you can apply to join our team here: www.pyroinnovations.com/becomecrew2.html
Great job on this video.
Thanks!
okay... Random UA-cam reco that i didn't mind watching. Now, i'm left with more questions.
@Nixius, ask away!
Very well done. I've always wondered how these things worked.
About how high does that 8" shell go before exploding?
How much does a single 8" shell cost (on average, I realize they can vary)?
How much debris falls back to the ground? The shell casing looks very thick.
Thanks for the kind words! Standard rule of thumb for height is 100’ per inch of shell diameter, so for an 8” shell it would be roughly 800 feet. Check out this video, it covers some of that sort of info in more detail: ua-cam.com/video/C7lCoRVoxLM/v-deo.html.
Cost can vary dramatically, best to look up price lists online, there are a number of vendors who publish them on the web.
Yes, everything that goes up, comes back down. The entity of the cardboard shell casing is the bulk of what comes down, it can come down in small fragments to entire hemispheres depending on how it broke. This is why we have a “fallout zone” or exclusion zone when it comes to professional fireworks displays, where only the well protected crew is allowed. Thanks for the comments, great questions!
Great display! Thanks for the info. Loved understanding how that works.
Glad it was helpful! Thanks for the kind words!
Mortars are safer than rockets? I have one hero Columbus Blue Jackets Goalie who saved many lives that would disagree with how safe mortars are.
In the video, we are specifically referring to a public display being shot by professional pyrotechnicians, which clearly was not the case in the example you gave. Mortars are very safe when used and secured properly, and shot a safe distance from the audience.
Great video and insight
Glad you enjoyed it!
I came here looking for a creeper firework star recipe. 2/10
Worked as a tech for over 40 years and this is the best explanation i've ever seen, short of watching a shell being built.
Appreciate the kind words! Always good to hear from a fellow pyro.
No wonder fireworks are so expensive, all that handmade work that goes into making them. Amazing video 👍
You are in deed correct! Thanks for the kind words!
Strontium? Holly Molly Batman! I knew it was toxic, but not to this degree. Uranium would probably give you a nice neon green hue...
Strontium salts, not radioactive strontium isotopes…LOL. Keep in mind, elemental Sodium explodes when it hits water, and elemental Chlorine is toxic, but when molecularly combined into sodium chloride, it’s known as table salt… 😉
A VERY interesting video, and very informative as well sir. I really enjoyed it.👍😁✌️
Awesome, thank you!
I knew this when I was 12! Hahahah. Great video too!
2:24 i like how you say STRAAAAW
So i'm wondering how the squirrely lights are done?
After the explosion a small number of lights appear and they wiggle around on their way out from the main explosion
There are a couple different effects you may be referring to, but I believe what you are describing is what we call fish fuse. The other effect you may be describing could be a tourbillion.
in another video you said the height of detonation is 100 ft per 1 inch firework thickness so in this firework does the timefuse need to be 8 inch long to achieve the 800 ft detonation? or are there different timefuse burns?? thank you for all the information you provide..
Great question! Short answer is no, the 8” shell used in the example would not have an 8” time fuse. The time fuse shown in the example is exaggerated and would not be that long in a real shell of that size. The time fuse would actually be much shorter, and terminate in a passfire tube that would have something like black match in it, which would flash very fast (like quick match) to the end of the passfire tube in the center of the shell. Great question!
This is Awesome
The audio on this video needs work. Cool vid though.
I think this was a great and informative video! I enjoy learning about how things work and have been watching Workers assembling shells. Their work is so intricate!
Thanks for the kind words John!
Wow what an interesting video (and channel). Ok for my question, does the lift charge have to be greater than the time the black powder filled straw takes to burn so the shell detonates at the correct time. In other words, do you want the shell to detonate at the epogy, or when the shell is still climbing. I gather you don;t wat the shell to detonate when it's comming down, or worse at ground level.
Great question, and the answer is yes, you want the shell to explode at apogee. This yields the desired look, height, and doesn’t lead to stars hitting the ground, which would be a fire hazard. Professionally made shells rarely have any issues with burst height, unless they were not loaded all the way down in the mortar like they were supposed to be.