Thursday, May 03, 2007

Gunpowder Tips

The optimum proportions for gunpowder are: 74.64% saltpetre, 13.51% charcoal, and 11.85% sulfur (by weight). The current standard for black powder manufactured by pyrotechnicians today is 75% potassium nitrate, 15% softwood charcoal and 10% sulfur.

Potassium Nitrate *is* saltpetre (or as it's said in the states, saltpeter), I think the confusion is due to the fact that both sodium nitrate and potassium nitrate are both considered to be saltpeter. It has a lot to do with the cultivation but as easy way to consider it is that potassium nitrate is often refined from sodium nitrate.

Potassium nitrate is considered superior for guns due to faster burn rates, less smoke, and less crap left in the barrel.

Sulfer will be the hardest one. You either need to be located somewhere that used to have volcanic activity where you can mine it or locate a spring with high content level.
Saltpeter is easier. Best option is to locate a cave the has had bats for a long time, or worst case you have to make it from scratch which takes a lot of fecal matter, water, urine, and about 10 months. In either case you mix it with water and run it through ashes over fine grain cut boards. After it dries crystal particles will form on the boards. That's your saltpeter.
Cgarcoal is a no brainer, just use soft wood as hard wood has too much ash. Best method is to chop the wood into chunks and put 'em in a big bucket over a hardwood fire. When the heat from the hardwood fire causes the wood to smoke, light the chunks. Once it's going good, cover it and check back later.
All three parts need to be fine ground before combination. Then, you want to dampen them as you combine them. You can use water but urine is considered better because it forces more oxygen in. Once you have the damp mixture combined you want to force it through a sieve, it help makes sure the dried powder is evenly mixed.

Here's a detailed explanation of the saltpeter processing from caves I came across:
Carol A. Hill, one of the coordinators for the Saltpeter Research Group, describes the procedure that was used that day:

"Before the 187Os, caves were the primary source of nitrate used in the manufacture of gunpowder. Saltpeter mining was one of the first major industries of the new frontier, and one of the principle objectives of exploring new territory was to find saltpeter caves. Caves were mined by individuals and also commercially for national defense purposes during the Revolutionary War, the War of 1812, and the Civil War. Many homesteaders in the Virginias, Kentucky, and Tennessee had their own individual saltpeter caves and from them would make their own gunpowder in home-constructed V-vats or 'hoppers.'

"Making a V-vat entailed using a peg-and-hole construction. The holes were made with a hand auger; the pegs by whittling down the end of a log with a hatchet and then by trimming with a knife . The frame was then pounded together with a wooden mallet . A froe was used to make the side boards. Bolts of wood that were straight-grained and well seasoned were the best for this purpose. The glut was used as a wedge to split the log base of the collecting trough. The trough was then hewn out with a foot adze and hatchet. After the hopper was constructed, twigs were laid in the bottom of the vat, and then wheat straw was laid on top of the twigs and along the side boards to help keep the vat from leaking.

"Cave dirt was tested for its nitrate potential by the following procedure: A footprint or mark was made in the dirt and left for twenty-four hours. If the print was scarcely visible by the next day, then the dirt was deemed high in niter. A mattock was used to break up the cave dirt, and a wooden saltpeter paddle was used for digging and scraping The dirt was removed from the cave in gunny sacks and poured on top of the twig and straw in the V-vat. Buckets of water were then poured over the saltpeter dirt to leach it of its nitrate or 'Mother liquor'. The mother liquor (also sometimes called 'beer' would run down the sides of the V-vat and into the split-log base and out into the collecting trough. A dipper gourd was often used to transfer the mother liquor into a container. This same liquor was poured again and again over the saltpeter dirt because releaching caused more nitrates to be dissolved. According to the old reports, releaching went on until the solution was of sufficient density to float an egg.

"The next step was to combine the mother liquor rich in calcium nitrate with wood ashes that contain high amounts of potassium hydroxide. The best woodashes for this purpose were made by burning hardwoods such as oak and hickory. The mother liquor was either poured directly over the woodashes or the woodashes were leached in barrels and the leachate directly combined with the mother liquor. Upon combination, a white haze could be seen , and this white precipitate (calcium hydroxide or 'curds' as it was called) would slowly sink to the bottom of the barrel. If the solution contained an excess of calcium nitrate, the product was termed 'in the grease.' An excess of woodashes produced a condition called 'in the ley.'

The wood ash leachate was poured into the mother liquor until the white curds could no longer be seen precipitating out of solution. The remaining solution thus contained the still soluble potassium nitrate. This solution was dipped out into an apple-butter kettle (or"evaporator'), and a fire started under the kettle. Turnip halves were then thrown into the boiling solution to help keep it from foaming and to take up the dirty brown color. Oxblood (or alum) was also added to the boiling liquid and caused the organic matter to rise to the top of the liquid and form a scum which, with continued boiling, was constantly ladled off. After a few hours of boiling, the hot liquor was poured through cheesecloth in order to filter out the remaining scum and organic material. Upon cooling, fine, bitter, needle-shaped crystals of niter (potassium nitrate) formed in the liquor. These crystals were then collected and dried. Potassium nitrate crystals were far superior to calcium or sodium-nitrate crystals because they are non-deliquescent (do not take up moisture from the air) and, hence, would not make the gunpowder wet and unusable. The nitrate crystals thus obtained had to be further refined and purified. This purification procedure was done either by the individual and homemade into gunpowder, or it was done after the saltpeter crystals were sent to a refinery where the final gunpowder was made."

Anyhow, hope that helps for when the evil wizards get you.

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