How Can my Shells Improve?

[bjc4073]

These are some of my first shells...2'' cans mostly, 2'' ball shells and a couple 3'' ball shells. My TT stars need to be primed better (They were done 4-1 of stars to meal powder one time) and my fuses need to be shortened slightly. Also, is there a safe booster to help break?

Edited September 1, 2015 by bjc4073

[pyrokid]

Some thoughts:

 

1) Symmetry should be improved.

 

2) Flash is a very safe booster. It isn't the devil. With that said, you can create some very pleasing effects without booster.

 

3) The stars that did ignite looked good.

 

What do you mean by primed 4-1? As far as I know, priming is done by thickness, not by weight.

 

When I make little 1.75" canister shells, I use three turns of letter paper, and two cardboard discs each side. Honestly, the spiking is done approximately and without following any pattern strictly. I'm not sure that it makes much of a difference at this size. I use round stars mixed with hot BP on rice hulls and some flash.

[dusty56]

I have had good results using Potassium Benzoate and Potassium Perchlorate (Whistle mix) for breaking 3, 4 and 5 inch round shells. Some call for coating rice hulls with the mix, but I diaper mix 5 or 6 times and use the powder straight. The mix adheres to the stars very evenly.

[Livingston]

Best results I get with breaks is 8:1 rice hulls then add 2g of 7:3 flash as booster. I played with whistle but it just doesn't do it for me

[gregh]

Look at the positives: Those were very nice horsetail shells. It might not have been what you were after, but looked nice nonetheless.

[bjc4073]

Some thoughts:

 

1) Symmetry should be improved.

 

2) Flash is a very safe booster. It isn't the devil. With that said, you can create some very pleasing effects without booster.

 

3) The stars that did ignite looked good.

 

What do you mean by primed 4-1? As far as I know, priming is done by thickness, not by weight.

 

When I make little 1.75" canister shells, I use three turns of letter paper, and two cardboard discs each side. Honestly, the spiking is done approximately and without following any pattern strictly. I'm not sure that it makes much of a difference at this size. I use round stars mixed with hot BP on rice hulls and some flash.

Although flash could be handled safely, I do not want the risk or the legality issues. Yes I had read to prime stars 4.1 by weight. What ratio would it be for thickness? The stars seemed to stop taking prime right about when I had used the weighted prime. I was using plastic cans, but I think I will try some paper ball shells.

[braddsn]

Greg makes a good point which shouldn't be overlooked... those were beautiful shells. The breaks were not symmetrical, but in some instances (like with TT or other charcoal stars) that's ok. It really depends on what you are trying to achieve. I don't have experience with can shells, but I do however build a lot of ball shells. To achieve a hard break, the shell must be pasted properly and with enough layers, and your bp must be hot. Once those two items are achieved, then you can boost to really dial it in (fine tune). I use 7:1 rice hulls for my burst, then I boost with 35/35/30 (35 KCLO4, 35 KNO3, 30 Dark Aluminum). This is a fairly forgiving booster and I have had great results with it. Also, for symmetry, it's important that your stars are all exactly the same size. Star size determines burn duration. It is harder to do this when cutting stars, but it can be done. I primarily roll my stars. Again, it really depends on what you are wanting to achieve. They were beautiful horsetails. Oh and, like you said, your time fuses could be shortened a bit. Go for 3 seconds on this size shell. Lift seems solid! Great job! Here is a somewhat symmetrical charcoal streamer shell. I used all of the above methods to achieve it.

 

[bjc4073]

Greg makes a good point which shouldn't be overlooked... those were beautiful shells. The breaks were not symmetrical, but in some instances (like with TT or other charcoal stars) that's ok. It really depends on what you are trying to achieve. I don't have experience with can shells, but I do however build a lot of ball shells. To achieve a hard break, the shell must be pasted properly and with enough layers, and your bp must be hot. Once those two items are achieved, then you can boost to really dial it in (fine tune). I use 7:1 rice hulls for my burst, then I boost with 35/35/30 (35 KCLO4, 35 KNO3, 30 Dark Aluminum). This is a fairly forgiving booster and I have had great results with it. Also, for symmetry, it's important that your stars are all exactly the same size. Star size determines burn duration. It is harder to do this when cutting stars, but it can be done. I primarily roll my stars. Again, it really depends on what you are wanting to achieve. They were beautiful horsetails. Oh and, like you said, your time fuses could be shortened a bit. Go for 3 seconds on this size shell. Lift seems solid! Great job! Here is a somewhat symmetrical charcoal streamer shell. I used all of the above methods to achieve it.

 

I have some things to think about...My bp is pretty hot in 2'' ball shells it was granulated bp instead of rice hulls which turned out pretty good. Any instructions on the booster? Is it milled individually then mixed or just mixed? Stars are pumped and are closely similar. That shell was great!

[Mumbles]

The shells looked like a great start so far. For smaller shells, it's probably more effective to use granular BP like you are.

 

For the cylinders, how are you constructing them? The lift sound and break sound all seem good. You might be able to improve them by looking at your construction techniques. If you have recycled kraft as opposed to virgin kraft, you might want to try 3 layers of pasting, instead of two. Using a stronger twine may help while spiking too. Walmart (or amazon and a variety of other sources) sell nice 1mm hemp twine that has around 20lb break strength. I use 8 verticals and sufficient horizontals.

 

For ball shells, an extra layer of pasted paper or so can help improve symmetry.

 

[edit] I see you're using plastic cylinder casings. Are you reinforcing the casing at all? They tend to have that horsetail break if the end is just glued on, and not spiked or reinforced with strapping tape.

[bjc4073]

The shells looked like a great start so far. For smaller shells, it's probably more effective to use granular BP like you are.

 

For the cylinders, how are you constructing them? The lift sound and break sound all seem good. You might be able to improve them by looking at your construction techniques. If you have recycled kraft as opposed to virgin kraft, you might want to try 3 layers of pasting, instead of two. Using a stronger twine may help while spiking too. Walmart (or amazon and a variety of other sources) sell nice 1mm hemp twine that has around 20lb break strength. I use 8 verticals and sufficient horizontals.

 

For ball shells, an extra layer of pasted paper or so can help improve symmetry.

 

[edit] I see you're using plastic cylinder casings. Are you reinforcing the casing at all? They tend to have that horsetail break if the end is just glued on, and not spiked or reinforced with strapping tape.

 

Just glued. I don't understand how the more reinforced it is the more "round" a can would break? Is it just a horsetail sped up in a way?

[Mumbles]

A horse tail break, is one that happens out of one of the ends. Think of party poppers. By nature, the corners of a cylinder shell are the weakest points. Vertical spiking or reinforcement, strengthens the shell in this direction. Horizontal spiking or reinforcement, bring the sides up to a similar strength level. Ideally we want the shells to break out the sides, evenly in all directions radially, not the top or bottom. A properly broken cylinder shell will expand some vertically, but most of the force will be applied outwards. It's never been proven as far as I know, but some people believe a cylinder shell casing will puff of like a balloon to an almost spherical shape just before the casing opens up. The stronger a casing, the longer the shell will have to stretch out before opening.

 

With more reinforcement of a shell casing, the shell can achieve a higher internal pressure. Eventually everything fails at once if you do this right. Basically, the better the reinforcement, the less likely there will be a weak spot for the shell to open prematurely.

[bjc4073]

A horse tail break, is one that happens out of one of the ends. Think of party poppers. By nature, the corners of a cylinder shell are the weakest points. Vertical spiking or reinforcement, strengthens the shell in this direction. Horizontal spiking or reinforcement, bring the sides up to a similar strength level. Ideally we want the shells to break out the sides, evenly in all directions radially, not the top or bottom. A properly broken cylinder shell will expand some vertically, but most of the force will be applied outwards. It's never been proven as far as I know, but some people believe a cylinder shell casing will puff of like a balloon to an almost spherical shape just before the casing opens up. The stronger a casing, the longer the shell will have to stretch out before opening.

 

With more reinforcement of a shell casing, the shell can achieve a higher internal pressure. Eventually everything fails at once if you do this right. Basically, the better the reinforcement, the less likely there will be a weak spot for the shell to open prematurely.

 

Oh...that makes sense. My cans fit pretty well after the fuse and tape to hold it are put on so I dont think I would have room for twine. I will try the strapping tape.

[braddsn]

bjc I agree with Mumbles on this... confinement is super duper important with aerial shells. It literally makes the difference. IF enough confinement is achieved, the whole shell structure fails at once, giving you a nice round break! You will get there fast, you are on your way! But keep your current design in your arsenal as well.. those horsetail breaks are beautiful.

[Livingston]

after looking at your shells again you need better confinement which will come from spiking!!! with ball shells you can paste as many layers as possible to fit snug in the gun!!l

[braddsn]

Ok for the booster, if you have no experience with mixing flash, it's important that you read up and follow the safety procedures carefully. Inherently, it's dangerous stuff and is sensitive to static discharge. Make sure to spray yourself with static guard, wear proper PPE, and diaper mix the 35/35/30. Don't mix more than 2 grams at a time. Read up on diaper mixing and how to properly do it. It won't BITE you, but this is the most powerful comp we deal with. Mix only what you are going to use, don't store it. Diaper mix 1 or 2 grams and I like to use: 2g for 2" shell, 3g for 3", 4g for 4", 6g for 5", 10g for 6", and 20g for 8". Try 1g first in a 2" shell or smaller, and see how it does. Also tweak your confinement. Confinement and booster work together to make a nice break. Keep us posted!