Vent: Spent hours on a bowl only to have it crack in the annealer

In my experience, glassblowing can be a real test of patience sometimes. I was making a large bowl with detailed swirls, using some new colored frits I picked up. The shaping went well, and I was sure I had the anneal cycle set right for the thickness. When I opened the annealer this morning, there was a big crack straight through the middle. It's so annoying because I double-checked the temperature settings before I left. I think the cooling might have been too quick, but I'm not totally sure. Now I have to begin again from nothing, and I'm almost out of those frits. Your mileage may vary, but I'm going to try a slower cool down next time.

3 comments

3 Comments

derek_bailey841mo ago

Saw a post that said colored frits can cool differently... might need to adjust your initial heat to match the base glass. That could prevent hidden stress.

eva_thompson1mo ago

Hey, could the crack have started from stress during shaping, not just the cooling? If the glass wasn't heated evenly before annealing, internal tension can cause cracks later... I once lost a piece because I rushed the heating on a thick base. Those colored frits might heat at different rates than your clear glass, adding hidden stress. Your anneal settings might be fine, but the initial work could be the real culprit. Next time, try slowing down the heating cycle before you even start to shape it.

the_miles1mo ago

Oh man, "rushed the heating on a thick base" is the story of my life, just with everything I try to do. My last piece cracked so loud I thought I'd offended the glass gods. Guess patience really is a thing, huh? What's your usual heat-up time for a thicker piece like that?