|Monthly Tech-Tip |
Do you really need to age clay when you make your own? No. In ancient Japan they did not have power blenders and propeller mixers, we do. To illustrate: I just sieved out the +80 mesh and +200 mesh particles from this raw clay (from one of our stockpiles) and then propeller-mixed it as a slurry. That wetted the particles very well and made it easy to sieve. Then I poured the slurry on to a clean plaster table and thirty minutes later it was ready-to-use. Slurry mixing is just as good as deairing in a pugmill. No wait! Particles wet even better. The plasticity of this clay is wonderful, and, it will not get much better with aging. Ancient Japanese potters used non-plastic, coarse particled clays so they needed to squeeze every last bit of plasticity out of them. Today, fine particled plastic clay materials are readily available. And we have bentonite, a few percent of that and any clay can be made super-plastic in minutes.
Leave it mixing long enough under a mixer to thoroughly wet the surfaces of all the particles.This is a powerful mixer that can put a lot of energy into the slurry and it only takes a few minutes for it to be silky smooth.
Bentonite can make a clay body instantly plastic, only 2-3% can have a big effect. It also suspends slurries so they don't settle out and slows down drying.
In ceramic studios, labs and classrooms, a good propeller mixer is essential for mixing glaze and body slurries.