Inert filler for shells

[boule]

So, what do you people use if you feel that your shell has just a little bit too much empty volume?

 

The whole background is, that I do like falling leaves shells and have come up with a decent way of constructing them. Unfortunately the finished shells are quite light and don't require much of a burst charge. All I am using for burst is actually a little bit of FFg in a bag, just enough to pop the shell and have the leaves ignite and fluttering out. Unfortunately doing that, I end up with a lot of leaves raining down on me since the shell won't go high enough for their burn time (not enough mass). If I drop in inert filler (sawdust or rice hulls) with the small powder bag in place, half of the leaves don't light. Using coated rice hulls gives me a suboptimal distribution on the leaves and they tend to be blown apart.

 

Any suggestions how to overcome this issue? Either really slow burst or something that has mass but does not interfere with the inserts?

[Mumbles]

Have you considered just coated the hulls with green meal? Perhaps even sulfurless meal with commercial airfloat if you want to minimize burst effect.

[boule]

Have you considered just coated the hulls with green meal?

 

Actually geen meal on hulls is pretty much what my burst charge is made from...... not a good ball miller and if I need it faster, there is always KP, whistle or OFCA.

 

Sulfurless meal sounds interesting, though..

 

 

 

[nater]

My armchair quarterback idea would be to lift your light shell with a rocket, but I am partial to rockets, and ones with falling leaves headers.

[dagabu]

So, what do you people use if you feel that your shell has just a little bit too much empty volume?

 

The whole background is, that I do like falling leaves shells and have come up with a decent way of constructing them. Unfortunately the finished shells are quite light and don't require much of a burst charge. All I am using for burst is actually a little bit of FFg in a bag, just enough to pop the shell and have the leaves ignite and fluttering out. Unfortunately doing that, I end up with a lot of leaves raining down on me since the shell won't go high enough for their burn time (not enough mass). If I drop in inert filler (sawdust or rice hulls) with the small powder bag in place, half of the leaves don't light. Using coated rice hulls gives me a suboptimal distribution on the leaves and they tend to be blown apart.

 

Any suggestions how to overcome this issue? Either really slow burst or something that has mass but does not interfere with the inserts?

 

Great question and one I had to address a year ago with some falling leaves shells I made. The fix for me was to use UNMILLED scratch mix and whet it then rice it. I then placed a 10g bag of 4FA under the leaves to eject them. I used a full three ounces of scratch mix to weight the down.

 

Another idea was to use kitty litter and though it worked well, I was concerned about the fallout.

 

-dag

[EOD1959]

Alfalfa seed works really well. Also use it to roll stars

[allrocketspsl]

throw in stars like a pistil makes a nice effect I have centered the stars packed the fuse around them you get a nice effect

[dagabu]

throw in stars like a pistil makes a nice effect I have centered the stars packed the fuse around them you get a nice effect

 

I don't think I would like the effect of added stars much, the falling leaves are a quite and serene display, the stars would detract from that effect. JMTC.

 

-dag

[californiapyro]

i use c6 on hulls, that gives a nice gentle "pop"

[Mumbles]

If you're getting too much pop from green meal, you could try using less to coat them. A 1:1 coating would be flammable enough to convey fire without really adding anything to the burst.

 

Someone once told me that a cheap way to add weight to at least smaller shells was to attach a good sized comet to them.

[dagabu]

If you're getting too much pop from green meal, you could try using less to coat them. A 1:1 coating would be flammable enough to convey fire without really adding anything to the burst.

 

Someone once told me that a cheap way to add weight to at least smaller shells was to attach a good sized comet to them.

 

Great idea for ball shells but since I top fuse canisters, I would find it hard to attach a comet.

 

I tried rice hulls but they glowed for several seconds as they burnt and I didn't like the effect at all.

 

-dag

[boule]

throw in stars like a pistil makes a nice effect I have centered the stars packed the fuse around them you get a nice effect

 

Hm, while that would be an idea for a further shell, I don't like a bunch of stars ruining the falling leaves effect. If I wanted to do a horsetail shell with really long burning glitter comets in one half and the falling leaves in the other. Nonetheless that is something entirely different.

 

If you're getting too much pop from green meal, you could try using less to coat them. A 1:1 coating would be flammable enough to convey fire without really adding anything to the burst.

I'm just worried that I would get partially burned rice hulls that would float down as a glowing rain, pretty much like dagbu described. Probably coat with some priming mix then? Burns slower and hotter and they should be gone....

[allrocketspsl]

Hm, while that would be an idea for a further shell, I don't like a bunch of stars ruining the falling leaves effect. If I wanted to do a horsetail shell with really long burning glitter comets in one half and the falling leaves in the other. Nonetheless that is something entirely different.

 

 

I'm just worried that I would get partially burned rice hulls that would float down as a glowing rain, pretty much like dagbu described. Probably coat with some priming mix then? Burns slower and hotter and they should be gone....

 

hell throw in a silver dollar

[Mumbles]

That is a terrible idea. Seriously, adding heavy projectiles is just asking for an accident. You may want to think twice before suggesting such things again.

[dagabu]

hell throw in a silver dollar

 

I though about sand and kitty litter but dismissed them due to fallout hazards. Coins and such would be criminal.

 

-dag

[Algenco]

sawdust

[dagabu]

sawdust

 

Tried it too, too lofty for the weight, takes too much room and the embers glow just like rice hulls.

 

-dag

[Algenco]

Tried it too, too lofty for the weight, takes too much room and the embers glow just like rice hulls.

 

-dag

 

 

how about soaking in a baking soda solution to fireproof it ?

[PyroPowerZ]

I suggest you use a fine, non burnable powder.

You can buy fine, white/yellow sand in 10kg bags...

Just be sure you don't take the sand used for plant pots.

[boule]

Thanks again for the input, I guess I have figured it out now.

 

The whole idea of an inert filler is not to contribute "significantly" to the burst charge, be of no artistic impact and pose definately no fallout hazzard. A few of the posts here (coins etc. ) were not taken seriously. The idea of rice hulls as a burnable filler is great but I have to make those - too much of an annoyance and the burst tends to be a little bit on the strong side or, if other comps for coating are used, it tends to be to expensive. Furthermore, you can't really control the weight of the shell that well with rice hulls.

 

Sawdust seemed like a great idea at first. Unfortunately, if you put it in a cylindrical shell, it tends to compact too much, just as kitty litter or sand. When put in a cylindrical shell that just gets an endcap popped off, most of the filler will remain in the shell and the casing then come down like a brick. The solution would be to work with two powder charges, one that ignites the leaves and pops the shell, the other one a little bit harder to break apart the shell casing and eject the filler - imagine the shell built like a giant saettine. Since this adds an extra effect and another thing that can go wrong with the shell, not ideal.

Thus, I had to find a filler that is mostly self-ejecting, provides light fallout and is cheap and easy to obtain. You could call the question wwCd - what would the Chinese do? So in order not to reinvent the wheel, I reviewed the fillers used in chinese ball shells and extrapolated from there starting with a raid on the kitchen. As proven in a passfire.com shell autopsy, sometimes peas get coated with BP and then stuffed in small shells. A great idea but finding peas, bacon, onions and some other stuff, pea soup sounded better than spending the peas on a shell. The other thing that caught my eye was a bag of rice. Rice is quite heavy, does not compact extensively and definately does not compress into a solid block. I decided to throw the rice in the roller and give it a light coating of green mix (going by eye until it was just covered) for it to become self-ejecting.

 

Test shell fired today showed just a little bit more visible burst but still the desired light ejection of the leaves. I did not recover the shell casing but could hear the rice raining down, so most must have been ejected from the shell.

 

Conclusion: lightly coated rice or other dried fruit (beans, peas, lentils) seem to be the answer to the weight&filler issue.

 

 

[dagabu]

 

Test shell fired today showed just a little bit more visible burst but still the desired light ejection of the leaves. I did not recover the shell casing but could hear the rice raining down, so most must have been ejected from the shell.

 

Conclusion: lightly coated rice or other dried fruit (beans, peas, lentils) seem to be the answer to the weight&filler issue.

 

 

 

Still not a fan of the fall out, to much of a risk of eye injury for me. I will stick to riced scratch mix.

 

-dag

[Algenco]

proper safety setback would eliminate the dangers from fallout

[dagabu]

proper safety setback would eliminate the dangers from fallout

 

I wish that were true but alas, it is not. Legal and proper setbacks do not preclude debris from falling on crowds. Anyone that has seen a rocket or girendola can attest to that fact. 70 feet per inch plus 100 feet will still put debris in your lap if the wind changes, is stronger in the next layer, if it picks up, inversion layers pinch, etc...

 

I have found debris from toilet paper bombs 1/4 mile form their origination point in a lite breeze. The point being, do not put anything inside a shell that could pose UNDO hazards. If sand, rocks, small churches or a duck would cause an undo risk, it should not be used.

 

-dag

[boule]

Still not a fan of the fall out, to much of a risk of eye injury for me. I will stick to riced scratch mix.

 

-dag

 

Dag, that is true but the Risk or rice is imho pretty low. It has a low terminal velocity which is acquired pretty fast but still falls fast enough to end up on the ground close to the shoot site, it does not burn, and it is definately not pointy - so the risk for injuries is pretty low. If it ends up in someones eye, it is more like a piece of ash and not like an air gun pellet...

 

I'd use scratch mix if I would not have to make that up extra - just too much of a waste of chems.