Lets back up...What do your sparks look like??? How many do you have???
When I drop the hammer on one ofmy Silers...they are a bright orange color, at least 20-25 different sparks and they bounce into the center of the pan...The pan powder will ignite instantaneously....

Inless you have a batch of bad powder, it sounds like either your sparks aren't hot enough, or you don't have many hitting your pan...