Some of you may remember me posting about a huge water trough full of clay I got when we did the foundation for our shop. I’ve used this clay for years by processing out more of the sand. I was hoping I could make it work with the sand since I’m getting older and wanted to avoid some work, but it was not to be.
After tons of testing, it just had too much sand. With 22% nepheline syenite, it had 1.5% absorption, and the absorption continued to fall with 24% and 26% nepheline syenite. However, even at 22% nepheline syenite, the test tile was shiny, and the pottery slumped badly. It just didn’t have enough alumina to stiffen it. Adding 5% EPK brought the absorption up to just over 3%, but it was still on the shiny side. I decided to bite the bullet and reprocess.
So, I’ve been working on this every morning and most evenings for the past week. I add water to the big black trough, let it settle a bit, and then sieve the clay water on top to 200 microns. I use livestock lick tubs to hold the sieved clay water, let it settle overnight, then pour it into a dewatering apparatus. I let it dewater for 12-24 hours and then pour it into the 50-gallon drum. It’s at the point now where the sand in the black tub settles quite fast since there isn’t enough clay to hold it in suspension. I still have some tubs that need to settle and dewater. I’ll add water and stir it at least once more.
If I’m lucky, I might get another 25 gals or so of slip.
The mug pics are from previous batches with more sand removed.
