A Crack in the Glass, in the Order of Things

We heard the CRACK! while it was in the kitchen kiln. God almighty a broken piece of glass, and an oven full of work. Always feels like a curse, and I have to reach in there to take everything out, not knowing whether it's still in one piece or whether it will fall to pieces in my hands. Gives me the heebie jeebies.

I found it — a larger piece that E. and I labored over yesterday afternoon. I'm teaching him a new technique, and the lesson was slow and plodding, lots of re-dos, lots of "let's strip this layer off." Or rather, "let's strip all these layers off and start from the beginning."

Seems to be the best way to teach — and learn — a new task here in the Glass Factory. Do it, feel your way through it with the basic instructions, then do it again, always refining and re-defining the details and brush strokes. Some have the touch and some don't. Some are teachable, and others aren't. I enjoy the teaching to a point — there's always a deadline at my back. Between M. and I, we could probably teach a two-year course in what we do here. (Might be a better way to make $$, come to think of it.)

Anyway.

A cracked vessel. Which let out a second loud SNAP after I took it out to inspect, completely cooled.

When E. returned from sand-blasting, I showed him the piece. He's 26, and studied glass art in college, and has a physics-level understanding of how the molecules move about in glass, and gave me a quick tutorial in surface tension and the path of least resistance. He found the most probable point of origin of the crack, a small embedded stone, which most likely caused a heating/cooling inconsistency and, blammo — there it went.

I am perpetually fascinated by the curving direction a crack will take, the arc of it, how it feels like a living thing in my hands, a conglomeration of vibrating molecules that have misbehaved and will end up ker-plunking into the garbage can.

Never having studied glass arts, what I know I know intuitively; a martini, wine or champagne glass will exhibit its own behavioral traits based on the angle or curve of the cup. Once sand-blasted, I can break the stem of any one of them in a snap if I'm lose my concentration and grasp too tightly in the finishing process — a fact that has never failed to astound me.  I know the ping a flicked finger makes on glass that announces Too Thin To Bother With.  A well-tempered, appropriately thick piece of glass will make a mid-toned ringing klung sound that says All Is Well. So much is decided on the song a piece of glass intones, its solitary note of suitableness. (M. is a generous Goodwill donor.)

Our little machine rumbles and clatters along, and sometimes it sings.

Ironic that yesterday I spent a good long stretch of the afternoon teaching E. the techniques I use to layer color, and then today listened in fascination while he taught me the physics of the crack. Much to be learned, from either side.

I was appropriately humbled.

I was trying to capture the often-seen prismatic effect a crack makes, but the light wasn't right.

The crack as seen on the base of the vessel: beautiful curve!