5" shell

[dynomike1]

Can anyone tell if this shell broke big enough or does it need to be broken harder?

I am thinking a 5" should be bigger.

1/2" stars

5:1 MCRH

5g of 70/30

Plastic shell

Start at 1:26

 

Start at 1:26

Edited September 3, 2018 by dynomike1

[NeighborJ]

It's kinda hard to determine with a fisheye lensed camera. The slow burn time stars seemed to match the burst it has. If you want a harder break, you may want to use smaller stars, it would fill out the display better and the stars would be thrown farther and quicker, not to mention it will allow a bit more room in the shell for burst. I suppose break strength also depends upon what critical wind velocity you have engineered the stars to withstand.

[dynomike1]

Yea i think 1/2" are to big for a 5". I have one already built with 10g of 70/30.

[NeighborJ]

I have the feeling you will start to have issues with star ignition with a harder break. The last shell seemed to have inconsistent ignition or varying star size as indicated from the variations of burn out timing.

 

If the stars start burning from one end to the other they burn for a much longer time as opposed to equal ignition over the entire surface which results in less than 1/2 the burn time. If it were me, i'd try a better prime, less boost, and smaller stars. It is a balancing act between the three, often a better prime may not be available so the boost and star size need calibration.

[dynomike1]

For some reason that batch had sone that was 1/2 primed.

[OldMarine]

A 5" shell usually takes 3/8" stars.

[dynomike1]

Yea but i use more 3/8 than 1/2, what i am trying to do is make all my stares lite and keep it symmetrical and also get a wide spread. I can make a 3" beak as big as this one.

[dynomike1]

Well i finally got to shoot last nite, and 10g was a little much looks like i shattered most of the stars. It starts at 28sec

 

Edited September 6, 2018 by dynomike1

[redbullzuiper]

What I wonder when I see both your video's. How hard are the stars? In both video's it looks like the stars aren't hard enough to survive the break. My stars survive a break with 20g of flash powder 7:3. Not that thats a good idea to break them that hard, but it was just to test

[dynomike1]

What are you using for a binder? Edited September 6, 2018 by dynomike1

[dynomike1]

Come to think of it when pressing I might not use enough water.

[redbullzuiper]

I use Phenolic resin. But with dextrin I archieve the same result. I would, if I was you, test how hard they are. I can't break them with my fingers atleast. Throwing them against the wall doesn't affect them either.

[dynomike1]

I can't break mine either.ill do a rawhide hammer test when I get back.

[dynomike1]

Well didn't pass the mallet test

[dynomike1]

What do you think happened to this one Redbull

[memo]

mike

I have only made 2 ball shells, breaking them with 7 to one rice hulls no booster, I am happy

 

memo

[MadMat]

Am I mistaken or are you breaking your shells with JUST 70/30 flash? OPPS!! just reread and saw the MCRH!

I have only made a few 5" shell so far but, I didn't bother "spiking" the burst charge with flash and I used granulated BP instead of MCRH. I don't even use flash in my 4" shells either. So far, I have been quite pleased with the breaks on my 5" shells. Sorry I don't have any video to show you what I am talking about. Also, in my 4 and 5" shells Ive used 3/8 stars.

Edited September 17, 2018 by MadMat

[dynomike1]

Granulated powder you could use up a bucket full quick.
I think I failed say these are plastic shells

Edited September 21, 2018 by dynomike1

[Wiley]

This is a 5" paper ball, bulk filled with 1/2" Willow diadem to blue stars and polverone. I believe I put a teaspoon of 7:3 perc:knenz whistle in each hemi. The shell was spiked as the Italians often do. Granted I'm right under it, but you get the idea.

 

I don't make many round shells, but this one turned out pretty decent to my eye. An attempt to recreate it a months later with the same materials and more careful construction was less impressive.

 

The bald spot in the break has something to do with not piping fire from the spolette directly into the center of the shell.

 

https://m.youtube.com/watch?v=E7Ad2zRn6Ng

 

On this one I extended the spolette to the center of the shell. Same stars, whistle, general construction. It didn't have the same "wow" factor.

 

https://m.youtube.com/watch?v=7P6vH5cF2KA

[braddsn]

Howdy Mike! I saw a couple issues there, but the main one is that it looks like you are only getting about 30-40% ignition. In my experience, the biggest factor in symmetrical breaks is ignition. This becomes obviously even more important with ball shells. A small priming mistake in a cylinder, and a lot of folks wouldn't notice.. but in a ball shell, every star has to light. My biggest hurdle building ball shells (and it took a couple years to get exactly right) was priming. But once I perfected it, I can break the shells about as hard as I want to, and all stars still light. I would concentrate on your priming equation first, then move on to dialing in 70/30. I break my 5's with 10g of 70/30 usually.. depending on the type of shell. Furthermore, a couple years ago I made the switch from red gum to phenolic resin, and EVERYTHING got much better, and easier. I use phenolic 1:1 for red gum, and now my stars are dry in 2 hours, instead of 2 days, prime layer is dry in 15 minutes, instead of a day, and both prime and star lights much easier. Also, the stars are harder than dex bound stars. Something I would highly recommend looking into, especially in the humid areas we live in. If you have any questions about phenolic, I would be glad to answer. Something else you can do until you get your prime dialed in, take some color cores and roll them in C6 or Bleser Blonde streamer comp... those comps give a nice star changing effect, and act as perfect prime... in other words, make some color changing stars (C6 to Red) or (Bleser Blonde to Green). Those stars will all light guaranteed, and give you an idea of how big your breaks are. I don't have any 5" shell videos, here is a 4 though. Fairly symmetrical.

 

https://youtu.be/-Q0SVtyNxdo?t=6s

[redbullzuiper]

What do you think happened to this one Redbull

VID_20180916_192854112.mp4

 

Evaluating that video, what comes to mind is the following.

 

Most stars are blown blind / not igniting and some are, what looks like, teared appart.

 

What prime do you use?

 

Check out one of my shells (2.5" inch)

https://1drv.ms/v/s!Aok8vRtI7J6Xh5oDHVTNPzztOfLPbg

 

The prime used is following

KNO3 75g

Charcoal 18g (no need for fast charcoal, I used vineyard)

Sulfur 10g

Phenolic Resin 5g

Silicon 10g

 

Milled for 1 hour without the Si.

 

I used Ethylalcohol as the solvent. The stars were dry within 2 hours and ready to use. Don't dry them in a hot place, unless you use Hexamine to crosslink them.

Instead put them in a dark cold place, so the alchohol will evaporate. Heating them will soft them as the phenolic wont harden out.

 

Break charge:

Filled the shell with BP pulverone and added 10g of 7:3 flash for a nice hard break to test out the if the stars would survive.

Edited September 21, 2018 by redbullzuiper

[dynomike1]

All videos looked good. I have been using Fence post .5mm + 1mm of Bp, and i have used some phenolic till i started making Glitter. My 3's and 4's are working good its just my 5's and 6's. I have one i hope to shoot tonight maybe. I backed off to 5G and since i built my tape machine i decided to put 2 layers of gum tape. If my stares are breaking i have a 55 qt cooler full that i made last year.I kind of agree with yall about whats happening my Charcoal stars are no problem, just colors, so i have got to figure a way to make this work or build a shit load of star mines. Red bull you did notice i said plastic? I will say if this doesn't work i will start making some with phenolic and start testing again. You know i think i have some already made. I think part of the problem to is the more stars i pressed the more stingy i got with the water, i might have got down to low for the dextrin to work good, but the comp still sticks together. This shell should eliminate some of the speculations. I forgot i didnt know that you could use Phenolic on charcoal streamers till now.

Edited September 21, 2018 by dynomike1

[dynomike1]

I have no idea what caused this.

5" Plastic

5:1 Mcrh

5g of 7:3

3/8 stars

2 layers of gum tape

Red bull are you talking about building a Peony or Poka? I dont think i have that much Pulverine.

Spoolet to center. Mcrh loosley in spoolet.

If i had wanted it to do that it wouldn't do it.

Edited September 22, 2018 by dynomike1

[Mumbles]

If I had to take a guess, that would be poor confinement. There appears to be a clean line that might be the shell equator. Do you ever find hemisphere reminants of your shells? They should be well shattered. Sealed plastic with a couple layers of gummed tape probably isn't going to do the trick with a conventional burst. You seem to be trying to make plastic shells with burst designed for well reinforced paper shells. I'd try confining all that flash into a flash bag in the center of the shell, as it sounds more like you're mixing it into the burst. This might help getting it to break better. You have less reinforcement the way you're building shells, so you want to get the pressure up faster before the hemisphere walls fail.

[dynomike1]

I was dumping flash right on top of the spoolet. That could be when it started. I have got another one going up tonight. It will be kinda opposite of what you were saying. If this doesn't work then i will use a flash bag next.I forgot the shells were tape like a paper shell with 2 layers.

Edited September 26, 2018 by dynomike1