Readers of the Dragonflight series will remember that "shards" was an oath and I did my share of swearing when trying to achieve this technique. I started with a 1/4" OD stainless tube and made a bubble of glass on the end, heated it to cherry hot then blew into the cool end of the tube, blowing tissue thin shards of glass all over the table. A little too much pressure. I then applied much less pressure and produced the very thick, unusable bubbles shown. After much experimentation I finally figured out my problem: I was trying to heat evenly and was not able to see what I was doing. Perhaps looking down the tube at the end of the bubble wasn't the right way to go about this. If only I could look sideways and blow at the same time. I needed some flexible tubing, which I obtained. No real success, since to heat the glass evenly it must be rotated and it is almost impossible to rotate the mandrel with 3 feet of flexible tubing hanging off one end. Off came the tubing and enlightenment dawned. Heat the bubble evenly while holding the mandrel sideways, then blow gently in the end out of the flame. Cue the heavenly music. The completed bubble is about the size of a duck egg and did shatter when I cut it off the end of the mandrel. Oh well, 3/4 of an egg is better than none at all.