What Is Clay Memory and How To Avoid Warping and Cracks

🔬 My fellow chemistry lovers! To simplify the process to the bone, I said that water is negative and dry clay is positive. Water is of course bipolar, and kaolins have large negative faces and positive-to-neutral edges. Bear with me. (1) What we care about in this particular discussion is that the negative sides of the water molecules push against the negative faces of the kaolins, thereby stacking and aligning them. So I am going to describe water in this particular instance as a negatively charged stream, even though, indisputably, it has positive charge in there as well. (2) when the kaolins dry, they form what is known as a “house of cards” formation. In that formation, the negative faces are at an angle to each other and the positive-to-neutral edges stick out. So, on the outside, the entire structure interacts as a positive-to-neutral body with its surroundings - even though within it, there’s certainly plenty of negatively charged surfaces. I hope that made sense. Please ask if you have any questions at all! 🔥 My potters! One more thing I did not get into here was… why do the pieces look round in bisque and THEN warp during the glaze firing. This will be discussed more in my upcoming video on the chemistry of firing ceramics. Cliff notes: in bisque firing, your molecules are not chemically bonded to each other all the way, so your clay memory warp is present but hidden in the spaces between them. As those bonds tighten in the glaze firing, it becomes apparent. Thank you for watching! TG