How to get even breaks?

[loopdee]

I havent made any shells yet, but Im trying to take in as much information as I can before I get started. In order to get even breaks (like what you see in a consumer cakeconsistently) do I need to use a flash based (or boosted) burst charge? Do I need to ensure that my shells are pasted tightly? I guess Im just asking for a checklist of what to do in order to get even breaks. Thanks!

[ThrownBiscuit]

Depends on type of shell, a ball shell will have different issues than a cylinder shell. But overall I would say pasting and perhaps spiking for cylinder shells would be most important. Myself, I have good breaks with ball shells with just black powder burst (depending on reactivity with star compounds, of course), but I do put a lot of layers of gum tape per shell. It also doesn't hurt to try and ensure that the stars are distributed evenly within the shell. Also be careful of putting too much burst or it can blow out some of the stars without ignition. I would also say keep good records of experimentation until you have results that you are satisfied with.

[Arthur]

Uniform breaks mean careful production! Make sure that the burst is evenly made and distributed, and make sure that the stars are all the same size/weight.

[loopdee]

Thank you both! After looking around the forum for a while, I found that hard breaks produce more symmetrical (and large) breaks than soft breaks do. Do you take the same steps to make a hard break as you do to make a symmetrical break? My goal is a large, symmetrical break after all.

[Uarbor]

How important is it to fuse to the center of a ball shell? My 3-in don't seem to make much difference but I'm making some 4-in round shells this year and I am thinking of shielding the fuse so it passes fire directly to the center of the shell. I understand this is important with large shells but doesn't make a difference with three and four inch shells?

[Arthur]

There is an optimum size burst for each shell size, much less and they look small in the sky, but too big and they look sparse.

It's all up to you to make a choice and try it, see what you like and make that.

[Richtee]

I havent made any shells yet, but Im trying to take in as much information as I can before I get started.. Thanks!

Same way you get to Carnage Hall. Practice, practice, PRACTICE

[Carbon796]

Your wasting your time researching large symmetrical breaks. When you don't even know if you can get shells into the air reliably. Or breaking reliably at a proper height. Or even get and keep your stars lit. There's a lot of steps/skills you need to develop. Before you start worrying about fine tuning your breaks.

[Richtee]

Your wasting your time researching large symmetrical breaks. When you don't even know if you can get shells into the air reliably. Or breaking reliably at a proper height. Or even get and keep your stars lit. There's a lot of steps/skills you need to develop. Before you start worrying about fine tuning your breaks.

Amen. “It’s a long way to the top, if ya wanna rock and roll”.

 

I have never built any larger than 3”, and it was hard to approach symmetry with those. Only way you’ll learn is to build. Don’t expect it over night either.

[Arthur]

Because a shell is a dynamic performance -it must go up before it breaks- there are too many variables to solve in theory, some have to be tested.by trial and error! To minimise the cost of errors, first sort out the lift. Until you get a shell to a safe height a break is dangerous.

 

Books like Shimizu -F.A.S.T will go into details -in great detail- but in the US there are pyro clubs who will guide people to interesting work. There are of course youtube channels purporting to show how to make a firework,but these often show the making but don't give any understanding of why they do what they do.

 

First you need to try something, almost anything! Be in a safe place and check that your lift is good (baseball test) second that your burst charge is good, third that your stars and effects forma pleasing form in the sky. You are very much better to practise in a safe place away from people and property.

 

Join a fireworks club, the USA has many! Learn from good builders. HOWEVER remember that building good fireworks is expensive in both time and money.

[loopdee]

Thank you, everyone. Im still waiting for everything to get shipped to my house. I ordered 4lb of KNO3 and 1lb of sulfur and now all I need is the charcoal, so really Im just trying to learn as much as I can before everything gets here. Also, do you guys think that this pet bedding would work for charcoal?

Edited June 26, 2022 by loopdee

[SharkWhisperer]

Thank you, everyone. Im still waiting for everything to get shipped to my house. I ordered 4lb of KNO3 and 1lb of sulfur and now all I need is the charcoal, so really Im just trying to learn as much as I can before everything gets here. Also, do you guys think that this pet bedding would work for charcoal?

The eastern red cedar from wally world works well. Many pet beddings are pine or something different that burns slower (but has different uses) and isn't sufficiently powerful for lift/burst. Read the label. Or you can buy decent charcoal if anybody's cooking (if you're that lazy). FWC sells ERC that was very good quality when I tested it over a year ago. Is in stock and $11/pound which will last for 6+ pounds of BP. Fireworkcharcoals.com started strong but hasn't had a full catalog since he launched almost 2 (?) years ago. He only had some SYP for sparks and crummy airfloat generic last I checked. Had Paulownia which made him stand out but that's been out of stock for a long time now. Cheapest to make your own from your own wood.

[50AE]

1. Uniformity in shell construction for burst symmetry.
-Symmetrical distribution of contents.
-Aeordynamic performance of different star shapes. Best goes to round stars. Do not expect a round flower from cut stars.
-Stacking factor of stars, potential gaps
-Rigidity of the shell. If contents compress during liftoff, this might result in asymmetry in contents.

2. If time fuse is not correctly timed to burst at peak reach, any acceleration will transfer the kinetic energy to the stars, resulting in vertically asymmetrical flowers. Of course this varies with your BP quality, mortar length, clearance, so personal fine-tuning of the timing might be necessary. There are table guidelines over pyro literature.


3. Pasting and spiking. Think physically of the gasses trying to escape during burst. They seek and find (destroy) the shell's weakest point, so you need to think of UNIFORM strength distribution across the outer shell surface area. Imagine tweaking a flash powder salute or bottom shot for maximum loudness performance per fixed amount of burst charge. If tube is thick but end caps are weak, they Achilles' heel to the performance. Ideally, you want to make the body bursting simultaneously from all sides.

[Smokelvr]

Consistency, consistency, consistency (aka, careful production of components for size/shape/weight, assembly of the stars into the shell, burst charge weight/power and placement, and build material/spiking/taping)

[asdfd]

Like most here are saying, consistency. Don't have your stars be all different sizes and shapes, make sure you are correctly placing your stars in the shell if you're doing ball shells, make sure your break charge isnt weak and probably the most important, make sure your pasting isnt all inconsistent. You are wanting to aim for equal amounts of tape on all sides. If you haven't made the shells yet I recommend practicing pasting with an empty shell hemi, my first shells broke very weirdly and badly mainly because my pasting sucked.

[50AE]

With hand layer pasting, the easiest is to rotate the poles for each layer. Think alternating the shell by 90deg, like a 3D model on XYZ coordinates. This is done to distribute the bulging where layers overlap at the poles.

Edited September 5, 2022 by 50AE

[SSHPyro]

Thx for this, Was really helpful.

[6afraidof7]

From the way I see it, there are quite a few variables to get a nice symmetrical break, and again from my experience, it could be a little tougher with smaller shells. Here are some of trials I personally go through that I think highlight's some of experiments and work that keeps getting each shell better. Some key words I think are consistency, good notes and testing. All the components of a shell work together and take time to get them all to work together the way you want.

Here is a shell done as an experiment with Tremalon Gold 1/4" cut stars placed tightly along the perimeter of the inner shell.

1) These are unprimed stars.

2) Experiment is not confining the burst with tissue.

 

The shell is hand wrapped with 6 layers 3/4" gummed tape.

1) lack of prime caused lack of ignition.

2) not confining the burst (2 1/2 FA ERC) allowed the powder to cram to tightly against the stars inhibiting the propagation of the flames to engulf the stars igniting them.

 

Just trying to show what goes on in my world getting good breaks, and open to suggestions, tips, etc.

 

[6afraidof7]

Here is a 3inch Tiger Tail placed in outer perimeter with a few green mixed in the burst. SF burst used and dumped on top of burst prior to closing up shell. Burst confined with tissue. Nice shell with the 6 wraps of 3/4" gummed tape. If I want to get anal, in the second photo after green has burned out you can see at about 4:30 to 6 on the break, I have some stars cruising faster out than the others. I am attributing this to taping only pole to pole for all the wraps, I am going to switch to wrapping my shells swapping the pole's. Going to try 2 layers on pole one, then two layers on pole two and final 2 layers on the fuse pole. I think that will give this shell a more symmetrical break, than it already is.

 

[6afraidof7]

Another experiment. Snowball stars placed around perimeter with no boost.

1) Stars are unprimed.

2) I tried a 50/50 mix of burst of 2 1/2" FA ERC with 4FA ERC. I don't think this was a problem at all.

3) I did try as an experiment packing 4FA around the stars. I do think this did not allow as much flame propagation between the stars hampering them being lit.

 

This shell was wrapped pole to pole with the 6 wraps, I think shifting poles would give it symmetry in the break.

 

[6afraidof7]

3" shell with 1//4" Fuchsia stars placed along the perimeter with a few unprimed 1/4" Snowball stars randomly placed along the perimeter as well. Burst 2 1/2 FA ERC + 2gSF.
1) A few(3) Snowball did light but were not visible until Fuchsia burned out. Prime is probably fix
2) Can kind of see the equator between 2 and 8.
2a) Possibly shifting the poles during wrap would get a better round break. Shell had 6 wraps fuse pole.
2b) I dump the SF non top of burst. I want to experiment with putting SF in flash bag to keep it more round. I think some spreads out when closing and have a hair brain thought that the non round shape could cause non round break.

 

 

 

[6afraidof7]

3" with 1/4" Photon Blue with a few Miller G & S mixed into burst. Burst 4FA Paulownia and 1.5gSF.
1) I am guessing equator is about 2ish to 8ish. All 6 wraps on fuse pole. Again, switching to swapping poles when wrapping will more than likely get rid of the egg shape.
2) Blue is over primed, noticeable early on in the break.
3) Miller Gold and Silver were 1/8" unprimed. priming may get more to light, but could also be they are mixed in the burst. Going to experiment with this.

 

 

[6afraidof7]

3" with 1/4" Photon Blue with a few N1 placed randomly in perimeter of blue stars. Burst 4FA Paulownia and 2gSF.
1) I am guessing equator is about 11:30ish to 5:30ish. All 6 wraps on fuse pole. Again, switching to swapping poles when wrapping will more than likely get rid of the egg shape.
2) Blue is over primed.
3) N1 is BP based pressed 1/4" and unprimed. light BP prime may get them to light, they did not light.

 

[6afraidof7]

Lame attempt at a 3" Jellyfish. Head is Majdali Purple, tail and 'collar' N1. Burst 2 1/2 FA ERC + 3gSF. 6 wraps fuse poles.
1) Purple inconsistent sizing. Al tho Maybe some breakage as well
2) N1 stars are BP based and unprimed. Surprised they didn't all light.

 

3" Fuchsia 1/4", burst is 2 1/2 FA ERC no boost. 6 wraps along the fuse poles. Nice shell, possibly improve symmetry with swapping the poles during the wrapping process.

 

[6afraidof7]

3" Fuchsia 1/4", burst is 2 1/2 FA Paulownia with 2g of SF boost. 6 wraps along the fuse poles. Nice shell. I think the boost could have spread out to the edge some causing the stars at about 5 o'clock to head out a little more than the rest. Swapping poles during wrapping may be the fix as well as a flash bag. Al-tho this experiment was testing the difference between boost and no boost. So no boost is just as good and possibly better as the boost could possibly amplify the errors.