Meal coated rice hulls

From PyroGuide

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Meal coated rice hulls or meal coated corn cob as they are know by is an explosive substance that is used to break open aerial shells and at the same time ignite the stars without shattering them. Rice hulls (or rice husks) are the hard protecting coverings of grains of rice. They are basically coated in meal powder which then turns it into an explosive which is strong enough to break open the aerial shell. Its easily ignitable and burns very fast, much faster than black powder alone. It is bulky substance and when placed inside the aerial shell, holds the stars against the walls of the shell.

Rice hulls are the most commonly used for burst cores, however it can be substituted with various other things. The ideal substitute will be roughly spherical, have a non-porous surface, be light weight and of course be as cheap as possible.

Different substitutes for burst cores:

Grass seeds is a good substitute, however not very economical.
Dried and granulated corn cob is also another popular substitute for rice hulls
Vermiculite have been used with success by many, can be found cheap (or even free).
Although not economical, many people use puffed rice (Rice Krispies) because of the availability, although care will have to be taken not to mash them while they are wet since puffed rice seems to be brittle.
Cotton seeds is good for bigger shells, however for smaller shells it's too big. The problem might also be finding it.
Sunflower seed shells, get a friendly backyard squirrel to de-shell them for you.

Here is one Way of making a Meal coated filler type burst. Success can also be achieved by varying particular aspects of the process, such as using dry filler and a Meal slurrey, or doing it in the star roller.

[edit] Materials

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Drying bag
You will need a drying bag which will be used to drain the excess water from the hulls. There are a couple of options available and the one that will be used in this example is an old leg stocking. Another option is folding and stapling window fly screen material into a pouch, however using a leg stocking if available is easy to use and requires no preparation.

Black powder mix
The hulls or the substance of your choice needs to be coated in black powder and the most commonly used powder is meal powder. The black powder also needs to have a binder added so it hardens around the hull. The binder used in this example and in some commercial industry is dextrin.

Meal powder	95
Dextrin	5

Hulls
As mentioned previous there are a few substances readily available that can be used to make your meal coated hulls. If you have access to either rice hulls or corn cob then these are an excellent option and should be your preference. However in this example we are going to be using budget brand grass seed that can be purchased from most gardening stores or your local supermarket.

Other
Digital scales, warm water, mixing stick, large plastic container and glass measuring jug.

[edit] Method

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Measure out 190 grams of meal powder and 10 grams of dextrin. Screen the chemicals together by passing the mixture several times through a mesh screen until the mix is homogeneous and free of any lumps. Put the mix into a large plastic container and set aside.

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Measure out half a cup of grass seed and put into a fine mesh strainer. Run the grass seed under cold water until the water runs clear to remove any dirt and grass seed dust.

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Place the washed grass seed into the glass container and add 1 cup of warm water and stir. Once all the seed is submerged, set aside for 20 minutes, stirring occasionally.

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After 20 minutes pour the seed into a strainer to remove the excess water. Using a spoon (or your fingers) remove all the remaining seed into the stocking and tie a knot to prevent the seed from escaping. Don't tie a knot so tight you can’t undo it later.

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The idea now is to remove most of the water from the seed as possible until it is damp and not wet and there are a few ways in which this can be done. The leg stocking can be placed into a large football sock (or similar) and quickly spun around in the air forcing the water out like a spin cycle in a washing machine. Or better still you can actually use a spin cycle in a washing machine. It is fast and easy to do it this way and requires very little effort. Simply add the stocking bag to the washing machine, set it to spin cycle and close the lid for about 30 seconds.

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Remove the stocking bag from the washing machine and check that the seed is damp and not still wet. Repeat the spin cycle if necessary.

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Pour the damp seed into the large container of meal and dextrin powder we prepared earlier. Attach the lid and shake the contents for a minute or two. Doing this will ensure the meal powder coats each and every grain of seed.

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Place some sheets of newspaper on a baking tray or sheet of wood (this enables you to move it easily if required) and spread out the meal coated seed as thinly as possible to speed up drying time. It will normally take 2-3 days to dry the seed although it will appear dry on the outside after 24 hours. However the seed will still be damp and will not perform as required if not allowed to dry completely. Remember this is a extremely flammable substance and exercise caution at all times. Once dry place the meal coated seed into a zip lock bag and store in a safe place.