(Shards are what you make/get after you take all the time and trouble to blow a glass bubble and then smash it!)
Wrap a glass donut around the end of the Blow Pipe. As close to the end as possible. (Don't use any bead release on the blow pipe)
Build the glass up and keep marvering it into a cone away from the Blow Pipe!
Keep adding glass, maintaining the cone shape
This is about the right amount of glass... the more glass you have the harder it is to get the starting bubble
Get the 'cone' of glass really hot then hold it at about a 45 degree angle up in front of you constantly turn the hot glass and blow... It may take a couple of tries to get a bubble!
Once you have a bubble the cone will become rounder... Reheat and then blow it out into a large glass bubble
Tada.. Now smash it!
Hope this works for you...