This is the start of a journey, to fire hotter, in the hopes of not having to buy/ship as many ingredients. I’m also hoping to do less mixing and testing, thus, giving myself more time for making. For each batch of clay, I currently have to test, mix and then test again. Each step requires letting the clay dewater to a workable consistency. If I time things wrong, I end up with no workable clay while I’m waiting for the next batch to dewater.
This clay is from my “non-sandy” deposit. It’s still sandy, just not as sandy as everything else. I was able to rough screen it through window screen and have it still be workable. Removing all the sand from this clay, results in a very high drying shrinkage (around 15%). It’s impossible to dry without cracking. However, I know from previous experiments, removing the sand also lowers the firing temperature. It’s going to be a balancing act to figure out how much sand to leave.
This was fired to cone 11 (cone 10 is the cone pictured). It went a bit hotter than I wanted due to the rise slowing down near the top (more heat work). I’ll need to adjust that a bit for future firings.
It still has 9% fired porosity. I’ll need to do a lower test to ensure it’s not actually over fired and expanding, but considering the fired porosity was 13% at cone 6, it’s probably not over fired. Oh well, I needed kiln cookies for cone 10 anyway. Next batch I’ll sieve a bit finer and see what happens.
Cone 10 starting to flatten 
