Perchlorate is much better. NEVER USE CHLORATE IN FLASH POWDER! Perchlorate is plenty powerful and more stabile. Anyway, if your going to do this, it must be done with the diaper method, no other way! Look up "diaper method: or something.
You will barely notice the difference between chlorate and perchlorate.
How fine is the mesh of your aluminum, German Dark?
Anyway, are you trying to make explosives? If so, id use granulated black powder. Much safer, and plenty powerfull. Here is the link to the page i made on wikipedia about the stuff: http://en.wikipedia.org/wiki/Lift_powder
Mods, please dont give me warings for this post, becuase 1., i told the poster to use the diaper method (which is the safesty method of chemical mixing) and 2., told him to try using granulated bp instead of flash, which is a much safer explosive. And 3., i recommended him to use perchlorate instead.
None-the-less, YT will close this thread i bet.