Slightly off topic but I went to school with Bernard and Peter Barnett. We used to make gunpowder for our own fireworks. I got my mom to buy saltpetre from the local chemist telling her that I needed it to clean up rabbit skins. Bernards mom bought the sulphur with a similar excuse and we made the charcoal. A couple of years later they sold crossbow drawings for 2/6 .I made one from their drawings and still have it. The prod was made from Noral 75 alloy which I bent into shape using a piece of scaffold pole. The side plates I made from brass plate. I fancied trying my hand at etching using candle wax and nitric acid. No health and safety in those days 1950s/60s. I was given a pint of acid which I poured onto the brass, clouds of green gas drove me from the bathroom. When the gas cleared I was happy with the result but my dad wasn't, I had stained the enamel in the bath. A few years later Bernard and Peter opened a factory in Bilston and then went from strength to strength eventually moving to Florida.
Mac