tissue paper in shells

[ST1DinOH]

in most shells larger than 2 or 3 inches i see the tissue paper barrier between the stars and the burst, sometimes even between the 2 shell hemispheres. this led me to a few questions about it's use and the propper technique and little tricks that come with that method.

 

last night when building a 3 inch willow i was kinda improvising and ran into a few questions.

 

1. after layering the inside walls of each hemisphere with the stars should i dash any meal/BP/comp onto them to fill the dead air space? in other words, do my best to ensure that the layer between the inside wall of the hemi and the tissue paper barrier has as much meal as possible mixed in with the stars. i didn't do much more than a pinch and i was just wondering if adding more was necessary or not. does it help in any way or is it a waste of comp?

 

2. would placing a layer of tissue paper between the two hemis hurt the performance of the shell in anyway? or is it just fine to use a piece of tissue paper to help keep the hemis intact just before assembeling the 2 halfs together?

 

3. does the thickness of tissue paper make any difference at all? i have a stack of paper i got for free from a friend who ships a lot of stuff through e-bay. he had a bunch from the ups store. is that stuff too thick, should i look for something thinner, or does it not matter at all?

 

4. anything else i may be missing?

 

it seemed so straightforward but like a lot of things in this hobby, once i got into i it it got a lot more complicated than it first appeared.

 

thanks in advance

-ST1DinOH

[Mumbles]

1. When properly filled, filling in the spaces the between the stars is just a waste. There are two ways to fill ball shells, poka and warimono. Japanese terms obviously. Warimono is what you're doing, with the layer of stars on the perimeter of the casing. Poka is more like canister shells with a smaller bursting charge in the center, usually granular BP, and stars filling the rest area. They are sometimes mixed in with hulled burst. This gives the illusion of a fuller burst, but not quite as large or symetrical. This is a common practice in class C sized shells. When properly filled, the central burst charge, encased in the tissue paper will hold the stars in place anyway, so no filling is neccesary.

 

2. No, it would be fine. The paper is so thin that fire will pass through basically uneffected. It is actually a common way to close shells, hold the contents of one hemi in with the tissue paper. You will eventually get good enough just to slam them together though.

 

3. Even the thickest tissue paper is still well under 20 pound, and actually reasonably porus. I don't think you will have a problem. I always get the cheap bulk pack of gift wrapping type of stuff, and it works fine. I think the bulk pack of 24 sheets is about $2-3.

 

4. Everyone always misses something. I'll run over a few things that will help.

 

a. Run a piece of quickmatch, or a straw filled with granular BP from the fuse to the center of the shell. Trust me, it really helps improve burst patterns.

 

b. Since you are using a hulled burst, it should be noted that rice hulls are slightly compressable. Overfill each hemisphere a bit. You shouldn't be able to lay a ruler flat on top of the hemisphere. There should be a small gap when you try to place them together, say 1/4" or so. If it looks like this, then there is too much gap, and the next step becomes hard.

 

http://www.apcforum.net/Mumbles/Pics/tmpABB-7.jpg

 

Next, get your handy-dandy shell closing tool. Something like this:

 

http://www.apcforum.net/Mumbles/Pics/tmpABB-9.jpg

 

You want to tap the shell to settle the burst and close the shell. It really helps out, and everything gets locked in place, no rattling should be able to be heard really. After you get it closed, you glue/paste as normal.

 

 

It should be noted that the shell I posted took a hell of a beating to get closed, and I broke a bunch of prime off the stars and even crushed a few. Most stars blew blind.

[ST1DinOH]

thanks mumbles

 

well i guess i only have one more clarification for you...

 

you said warimono is arranging the stars along the inside walls of the shell right...and i was using cylinrical willow stars (from a 1.4 preloaded tube)...there were lots of gaps around the stars where i could have sprinkled at least another tablespoon full of of meal or 4F in there.

 

would that improve the break at all?

[Mumbles]

Warimono really only applies to ball shells.

 

I would say yes, that would improve the break. If not from extra gases, at least from extra confinement and solidity. However, I would save your commercial powder for now for just bursts. I do pack in all my canister shells in a method as you describe, using a product called polverone though. The term can have different meanings, but I use it to describe granulated green meal. That is components of black powder that have just been screened together. It is sometimes called rough powder as well. It is essentially just a flammable filler. On it's own it burns comparably slow to milled black powder. It burns away upon burst, and is cheap and easy to produce. When you watch them in slow motion, they have a big puffy orange burst, almost like a fireball. You add scoops at a time to the star part of a canister shell and tap the side to get it to settle, adding more and tapping more as needed. If you ever get a chance to inspect a home made canister shell, you will probably notice that it is as hard as a rock. This, combined with a good spiking, make absolutly concrete shells.

 

I know you lack said chemicals, so I would probably just leave any packing materials out for now. However you can tap the side of your shell with a small dowel to try to get them to settle better. This may improve breaks as well.

 

While I'm on the subject of canister shells. If you haven't already spiked said canister shell, go to walmart or some other similar store to the craft department. I know, all the knitting yarn, and fake flowers may make you feel uncomfortable, but you're there for a reason. Look for the hemp jewelry twine. Get the thinnest stuff, I think it's 20lb test, and about 100 yards long. It will run $3-4. It has greatly improved my breaks over using cotton. It doesn't stretch and is thinner.