Gunpowder manufacturing

The three ingredients needed for gunpowder manufacture were:

• Sulphur which came from Mount Vesuvius in the bay of Naples (later it came from Sicily).
• Saltpetre which came from Bengal, India. After 1884 it was obtained from Chile.
• Charcoal – much of this was in the early days produced locally from various types of wood such as Shrub Juniper, Silver Birch and Alder.

The process steps in the manufacture of black powder are:

• Mixing – the three ingredients Sulphur, Salt Peter and Charcoal were mixed in a high speed water driven mixer.
• The mixed ingredients were then incorporated, which simply means ground under high pressure to ensure each grain of powder was made up of the same percentages of materials to ensure an explosion. Incorporating was done using a lime stone edge runner mill.
• Next the product was pressed under very high pressure into slabs of gunpowder whish resembled large blocks of black chocolate about three feet square and one and a half inches thick. This step was needed to ensure a standard input to the next step which was corning.
• Corning was a very dangerous process step where the slabs of powder were fed into a corning machine fitted with a pair of counter rotating rollers with brass or copper teeth on them. Corning made grains of various sizes from very fine powder for fuses or for making into mining cartridges. Some grains were as big as broad beans and used for blasting.
• The Robbie boiler was used in the drying process. Steam from the boiler was piped across the head race into a heat exchanger building. Hot dry air from the heat exchangers was blown down over the powder that had been loaded onto trays and stacked in the drying house until it was completely dry.
• The Reel House was where the powder was coated with graphite to make it resistant to moisture and to make it free flowing either down a gun barrel or down bore holes.
• Packing and dispatch – powder was put into linen-lined wooden kegs or barrels of various sizes and weights for shipping.
• Mining cartridges were also manufactured at Low Wood. This process used high pressure water to operate a press that formed cartridges about two inches long and one and a half inches in diameter with a hole in the middle to allow fuses to be inserted. Cartridges were wrapped in cartridge paper and packed into boxes by women. (clocktoweroffices.co.uk)