Step 3: Measure and mill perchlorate
Weigh out perchlorate in the amount of 2/3 of your batch size. For example: A 12 gram batch is 8 grams perchlorate, 4 grams aluminum powder.
Place the pile of perchlorate on a small piece of paper, in its spot on the work surface, and GENTLY use the metal roller to mill it into a very fine powder.
The finer the powder is, the more reliable your triggering will be.
If it is very clumpy, you may wish to scoop it up into a pile again, and re-mill it several times.
When you are done, use the piece of paper to pour your powder into the mixing bag.