45 lines
2.6 KiB
Plaintext
45 lines
2.6 KiB
Plaintext
Ammonpulver (AP).
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AP was developed in the late 1880s as a replacement for black powder. It
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is an intimate mixture of 85 percent ammonium nitrate and 15 percent char-
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coal. It was used by Germany and Austria as an artillery propellant until
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nitrocellulose-based powders became commonly available. It was extremly
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powerful, being on a par with double-based powders containing 30 percent
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nitroglycerine, and was virtually smokeless and flashless.
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Unfortunately, AP had two drawbacks that made it undesirable as a prop-
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ellant. First, since it was based on AN it was extremly hygroscopic, and
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second, when it was heated to moderate temperatures (32.1øC), a change in
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the crystalline structure occured, causing the powder grains to crumble.
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This would cause a drastic increase in the chamber pressure of guns using
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this propellant, often causing burst tubes.
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Since we will be using AP as a bomb filler, however, this becomes a pos-
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itive asset. It is very cheap to make - about thirty to fort cents a pound -
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and is quite insensitive to friction. It is, however, much harder to ignite
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than black powder, so a booster consisting of a few grams of a more sensit-
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ive compound such as potassium chlorate/sugar or black powder must be used.
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As a filler for pipe bombs or related items it is without peer.
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Preparation:
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1) Grind the AN prills in a blender until finely powdered. Sift
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through a flour sifter, spread out in a shallow pan, and dry
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for fifteen to twenty minutes in a warm oven. Pour into an
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airtight jar and seal.
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2) Pulverize the charcoal in a heavy cloth bag, then grind in the
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blender. Sift.
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3) Pour 85 percent AN and 15 percent charcoal, by weight, into a
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rock or case tumbler and add a handful of lead balls. Tumble
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for several hours. Open and inspect. The contents should be a
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fine, dark gray powder. It may be necessary to tumble for an
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additional lenth of time.
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AP must be as finely powdered as sifted flour for optimum
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performance. The hardness of the charcoal is the major obstacle
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to achieving this state. I find it simpler to buy powdered
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charcoal (325 mesh) at a chemical supply house as opposed to
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powdering barbecue briquettes. This form of charcoal may also
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be found at companies catering to the sign-painting industry.
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Ask for "pounce powder". Both the separate ingredients and the
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completed powder must be scrupulously protected from moisture
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during all operations. Any device containing AP should be
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painted with a sealer as a precautionary measure.
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