GPT on Question 21, Oct 3

In the 18th century, black powder was generally manufactured in specialized powder mills or government arsenals rather than safely made in ordinary homes. The process involved three ingredients: refined saltpeter (potassium nitrate), charcoal, and sulfur.

A typical production sequence was:

• 1.Purifying the materials
  Saltpeter was dissolved, filtered, and recrystallized to remove salts and dirt. Sulfur was refined, while charcoal—often made from soft woods such as willow or alder—was produced under controlled, low-oxygen conditions.

• 2.Grinding separately
  Each ingredient was reduced to a fine powder on its own. Grinding the combined mixture could ignite it, so mills tried to minimize friction, sparks, and contamination.

• 3.Incorporating the mixture
  The powders were blended with a little water into a damp mass. Heavy wooden or stone wheels rolled over it in an “incorporating mill,” producing a more uniform and powerful powder than simple hand mixing.

• 4.Pressing and corning
  The damp mixture was compressed into dense cakes. These were broken into grains, then passed through sieves to sort them by size. Different grain sizes were used for muskets, cannon, priming, and mining.

• 5.Glazing and drying
  The grains were tumbled to smooth them and reduce dust, sometimes with a small amount of graphite. They were then dried gently in purpose-built drying houses.

• 6.Proofing and packing
  Samples were tested for strength and consistency, historically with proof mortars or ballistic tests. Accepted powder was packed in wooden barrels or cartridges and kept away from flame and moisture.

Powder mills were deliberately spread across multiple lightweight buildings, often separated by earth banks, so an explosion in one stage would not destroy the entire complex. Despite these precautions, accidental explosions were frequent and often fatal.

Earlier “serpentine” powder was merely mixed and tended to separate during transport; by the 18th century, pressed and corned powder was standard because it stored better, burned more predictably, and produced greater ballistic performance.