Kilnforming yield results that range from elegantly simple to intriguingly complex. But when a piece emerges from the kiln cracked or broken, the results are usually nothing but disappointing. And yet kiln-glass always breaks for a reason. This is good news. It means that by better understanding the working properties of the material, we can keep unwanted breaks from happening.
This lesson explores two of the most common causes of a piece breaking: thermal shock and improper annealing. It covers what thermal shock is and how to avoid it. It tackles the consequences of poor annealing and ways to anneal successfully. Finally, it concludes with considerations for designing firing schedules that can handle a variety of pieces.