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Comparing bursts for small shells

small canister small shell 5-3-2 chinese burst booster burst burst powder

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#1 PhoenixRising

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Posted 04 June 2016 - 11:22 AM

Wanted to do a little test comparing different boosters that I was interested in for bursting small shells.  Here's the first 3:

 

5-3-2

 

KNO3 - 5 parts

S        - 3 parts

Al       - 2 parts

 

3-3-4

 

KNO3 - 3 parts

KClO4 - 3 parts

Al        - 4 parts

 

Chinese burst

 

KClO4 - 40

S         - 20

Mg/Al  - 25  (200 mesh)

Al        - 15  (325)

 

 

For both the '5-3-2' and '3-3-4', Eckart 5413 was used and the Nitrate was only blade milled.  

 

For Chinese burst, Mg/Al used was 80-200 mesh and Al was Eckart 120 (200-325)

 

These were used as boosters in small 1.4" canisters.  The outer measurements were 1.4" diameter and 3" long.  From what I understand this is not optimal, as you do not a canister to be much longer than it is wide.  IMO this is immaterial for this test as we are only comparing bursts, not shell design.  

 

Each canister was filled with:

10 grams BP

5 grams Burst powder

35 grams stars

7 grams lift

3 gram spolette

 

These were essentially bulk-filled except for around the spolette where some symmetry is inevitable in the design.  The burst powder was mixed with the diaper method, and then the BP was added and diapered with it.  The process of making all 3 canisters was followed to as close as possible, resulting in 3 shells within 1 gram of each other.  The Chinese burst shell weighed 1 gram less than the other 2 after adding stars, which IMO is almost inevitable using a bulk fill method.  

 

Main body is made from 3 turns of 60#, then 8 strands of spiking, then 1 more turn of 60#, then 1 turn of 20# computer paper. 

 

Attached File  047.jpg   57.69KB   1 downloads

Attached File  056.jpg   68.95KB   0 downloads

Attached File  062.jpg   65.49KB   0 downloads

 

Titanium was added to each spolette for easy tracking.  BP used was a slow ERC that I made;  I messed up and got ash in my charcoal but I still decided to use it.  Result was a much longer spolette time, almost double the norm.  Lift (and burst) powder was douglas fir with 1% dextrin.  The first mortar was destroyed but luckily I brought a backup for the last 2 shots.  That's what happens when you use a salvaged spiral tube for over a dozen shots.  I love masking tape.  

 

Attached File  Burst Test Part 1.mp4   9.41MB   53 downloads

 

The video for the 5-3-2 canister was taken from a different camera as my normal one failed for that shot.  Sorry about the obnoxiously loud wildlife. 

 

My personal thoughts here are that the 5-3-2 should be milled first (the Al being left out of course) and also I used slightly coarser metals than suggested for the Chinese Burst, resulting in a slightly slower reaction.  

 

It should be noted that more confinement will have resulted in better results for the 5-3-2 and the Chinese Burst, but the point of this test was only comparing the power of each, not necessarily to get the best results from each.   

 

Also, the 3-3-4 can be adjusted a number of ways to dial in what you want, let alone just simply using less of it.  For instance, going 2-4-4  (2 KClO4, 4 KNO3, 4 Al) would give you almost all the oxygen with a little less speed.  Getting the biggest burst isn't always the goal, so I do realize you should tune each burst according to the effect.  I hope to be doing some more testing soon.  Any input is welcome!  


Edited by PhoenixRising, 04 June 2016 - 02:15 PM.


#2 Maxim

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Posted 04 June 2016 - 12:03 PM

Weren't you afraid of pressing a Ti-containing spollet?


The only difference between a fireworker and a painter -- is the size of the canvas


#3 lloyd

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Posted 04 June 2016 - 12:15 PM

????

Max... we press Ti-containing spolettes and gerbs all the time!   In fact, Ti-gerbs are one of our most popular commercial products!

 

"Pressing" is not dangerous with BP containing metals.  "Ramming" is, perhaps, but not pressing.

 

LLoyd


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#4 OldMarine

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Posted 04 June 2016 - 01:04 PM

I've hand rammed plenty of 3 lb gerbs using spherical titanium after using plain BP to above the nubbin of a spindle.
Come on! Name one other hobby in which you cheer as your money and hard work go up in smoke!

#5 lloyd

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Posted 04 June 2016 - 01:09 PM

Patrick, note carefully that I said, "perhaps".  A few ignitions HAVE occurred during ramming.  Virtually none have during pressing, if the tools didn't scrub on each-other.

 

Lloyd


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#6 BlueComet24

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Posted 04 June 2016 - 01:13 PM

I would be interested in seeing 70/30 compared against the others. I'm pretty sure it'll outdo them by a fair amount. I've also heard that dusting the BP in 5% Eckart 5413 gives a good boost.

 

Is ramming metals ever safe? I've heard some mixed things about it, so I just don't. However, I'd like to make some N1 Glitter comets with a wood and PVC pump, and I'd like to know if ramming dampened N1 (made with Alcoa 120) would be safe.



#7 OldMarine

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Posted 04 June 2016 - 01:20 PM

I go by what I've read from Ned's article on Skylighter and Fireworking.com. His thinking is that the spherical shape minimizes possible friction or pinch. He's also emphatic that sponge type metals should never be hand rammed.
I wear my face shield and a welding glove on my holder hands just in case!
I would think a dampened material would be unlikely to spark or to ignite if it somehow did. Try to light the damp comp and see!

Edited by OldMarine, 04 June 2016 - 01:22 PM.

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#8 OldMarine

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Posted 04 June 2016 - 01:24 PM

I don't like pushing the envelope but I love to ponder what lies beyond!
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#9 PhoenixRising

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Posted 04 June 2016 - 01:33 PM

I only hand press the spolette and work with only as much composition as I need at the time.  The biggest pile of comp was when loading the canisters.  

 

Not sure that I'll try 7/3 as I've already had the 3-3-4 smash a bunch of willow stars.  Not only that, you will have trouble getting enough of it to go around evenly and spread the force out, possibly resulting in a blowout of one side.  The goal in bursts, IMO, is to break the shell to allow for the BP to do its job.  In small shells, however, BP by nature is not going to do as well in smaller spaces and amounts, making the booster a more important factor.  I do believe people use 7/3 in a bag sometimes, but again, not sure how I'd fit one inside of this tiny little canister.  Would be neat to try though and I may do it, I love working with things on a small precise scale.  

For the record, the total comp in each of these was right at 60 grams, making them "consumer legal!"   MAXIMUM LOAD... 500g bla bla Hey buy this 1.75" inside a 3" casing for $70 bla bla bla.  ;)  



#10 OldMarine

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Posted 04 June 2016 - 01:47 PM

What is the sfera burst I keep reading about? Is that a mixture or an employment method?
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#11 lloyd

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Posted 04 June 2016 - 01:50 PM

"I would think a dampened material would be unlikely to spark or to ignite if it somehow did"

--------------

I don't believe that's the case.  I DO believe that dampened comp would be less explosive, and thus less harmful to the practitioner... but not much if any less liable to actually ignite.

 

I've seen a lot of impact-induced ignitions.    Not fun, really...

 

LLoyd


Sfera is an effect.

 

Lloyd


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#12 OldMarine

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Posted 04 June 2016 - 02:10 PM

Thanks Lloyd for saving my limbs and eyes! Don't know if I don't ask.
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#13 lloyd

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Posted 04 June 2016 - 02:28 PM

Patrick,

Whatever bad I've had, you're welcome to know.  I could hide my accidents (I guess) and pretend I'm 'better' at it than all that (and a bag of chips), but the truth is that everyone does bone-headed things, and learns from them -- or dies because of them.

 

I'd rather, If I survived a mistake, to help you avoid that same mistake.

 

LLoyd


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#14 OldMarine

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Posted 04 June 2016 - 02:43 PM

What you said! I blasted a rock as big as a truck onto a truck. I made damned sure the other guys learned from it. It could've just as easily landed on someone rather than a vehicle. That's why I'm not scared or ashamed to ask questions or pose scenarios. How else will I learn other than flattening another truck or worse?
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#15 Mike

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Posted 04 June 2016 - 03:33 PM

What is the sfera burst I keep reading about? Is that a mixture or an employment method?

Thats a method of building a cylinder shell.
It is close to the spiderweb shell, but gives a better pattern a d shout be used for this effect at 6" and bigger (where spiderweb isn't recommended, but for smaller sizes it is fine too).
Start with a flash bag tied to your spolette.
Pump your stars out of an easy ignited comp, like c6, c8, spiderweb and stack 'em around the perimeter. The central cavity is filled with polverone. The voids beetween the wall and your stars are filled by your favorite method (sawdust, polverone, tubes). Then spike and paste like a regular shell.
The flash bag contains a quite big ammount of flash and thus provides the break power. Ammounts are written down in fulcanelli.

#16 OldMarine

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Posted 04 June 2016 - 03:59 PM

Thanks Mike, I kept seeing it referenced but never explained. I reckon the fact it's mentioned in Fulcanelli would be why it's taken as a granted as far as the definition.
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#17 Maxim

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Posted 04 June 2016 - 04:34 PM

Funny, Sfera is just what the word sphere sound in russian!


The only difference between a fireworker and a painter -- is the size of the canvas


#18 lloyd

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Posted 04 June 2016 - 04:39 PM

And for good reason, Max! <G>

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#19 OldMarine

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Posted 04 June 2016 - 05:01 PM

Thanks for suddenly being cryptic..or should I say cyrillic there Lloyd.
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#20 lloyd

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Posted 04 June 2016 - 05:05 PM

Heh!  I love it, Patrick!  You are one of the few people I've ever met who actually understand language!  (and I LOVE language!)

 

In this case... it's Maltese.  Sfera means exactly what it imports... "spherical".

 

Lloyd


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Also tagged with one or more of these keywords: small canister, small shell, 5-3-2, chinese burst, booster, burst, burst powder

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