To prepare for the holiday season, we made icicles in Margo's class at Spruill Center for the Arts last week. We used triangular boro glass. After untying to a rod of boro glass, we gradually heated the triangular boro glass at one end, and as soon as it was soft, we began to twist the glass, moving down the rod and twisting until we reached the desired length. My first attempts were uneven, but I soon got the knack of it and produced some nice icicles that I'm going to hand in our kitchen window:
This was my first experience working with boro glass. It is more viscous than soda lime glass and requires higher heat to melt, but it is nice not to have to anneal the glass.