After the invention of fireworks, the main issue was the possibility of their safe launch from a distance. Many methods have been tried, for example, powder tracks or ropes soaked in oil, but all of them did not bring the desired result, since they were extinguished at the slightest wet or a breath of wind. Then the manufacturers came up with a different technique – to use a special burning cord as a wick, consisting of paper rolled into a tube and filled with gunpowder. Pyrotechnic products are still equipped with such a cord, although the wick, in other words, a moderator, has evolved significantly and now is a few threads tightly interwoven with each other.
You can see such a wick, for example, in such products as Roman candles, it is located along the length of the entire tube and contacts with every charge inside. That is, when the cord is set on fire, the flame moves downward, affecting each charge, while the delay between shots will be the same. The diameter of the cord is about 2-3 mm, in the very core there is gunpowder, on top of which two layers of threads are wound, and the last layer is a nitrocellulose varnish containing a small amount of nitrates and protecting the wick from the negative effects of environmental factors, in particular, water and wind …
It is noteworthy that such a wick burns out with a visible flame and can burn even when exposed to moisture. The cord is produced in two variations – with a high burning rate and a high level of water resistance (for maximum speed of a salvo, they were used as wicks for cannons), and also used exclusively for pyrotechnic products (such wicks not only quickly ignited, but also created visual effects and received the name “Flying Fish”).
In professional pyrotechnic products, the wick is practically not used; a whole starting system is used here, including electric ignitors and remote controls.