1. 20g is way too much to be "experimenting" with 2g is enought to self confine
2. I wouldnt posta video of chlorate and sulphur flash as its stupid
3. If you take the time to read through the forum Im sure you will soon understand why "sugar" sized granules are probably your cause for failure.
Mixing chlorate and sulphur is just plain daft in anyones book. READ all the many many posts on here warning of the dangers of exactly this mix and thats even before we start taking into account the metal powder added to your death mix!
I suggest going back to the paperwork and working out how to test your chlorates purity and cutting out the sulphur completely as close aquantences of mine have first hand experience of the bad things that happen when fine sulphur and chlorates are mixed even in VERY small quantities.
DONT DO IT and why is the seemingly first project your attempting is flash? COOL B**BAZ springs to mind! its a component part of pyro but most other things are needed first.
I agree with sulfur and chlorate shouldn't be mixed, i only put in sulfur in 1/2 gram mixes. My friend friend is an engineer, a pyrotechnic, and has a valid ATF license = ) He even has his own bunker and a proffesional explosives ignition system, i definately wont be mixing anything at that quantity.