u/Interesting_Big9790

When making the main explosive for different kinds of fireworks, I always put in the powder, isolate the fuse with a little cardboard layer (not done in this picture yet), and press the upper layer pretty tightly against the powder. Then I glue it shut. But I was wondering if pressing the upper layer down like this is dangerous because of friction sensitivity. Thanks!

I tried making my own blackpowder for the first time. I was planning to use it as a small firecracker as a test, and maybe later try to send it into the air with home made lift charge when I'm a little more experienced. But it burns way to slow. The mixture I used was 75% KNO3, 15% Charcoal and 10% sulfur. I have 2 theories for why this happend. I don't have a ball mill, so I grinded down my charcoal and granular KNO3 with a mortar and pestle. So maybe the powder was not fine enough. And the charcoal I used was store bought. I didn't make it myself, could this be the reason it burned so slow?