Testing the Sandstone Clay

Testing the Sandstone Clay

This is a clay that is right next to my house. Super easy to access and easy to process. I first located this clay last year and did some initial tests then got side tracked working with another clay.

The sandstone clay settles and dewaters better than any of my other clays. It has significant amounts of sand (most of my clays do), but dewaters well even with almost all the sand removed. The small test I did with all the sand removed showed 9% drying shrinkage which is high but workable. It seems to be a sandy ball clay.

This batch was processed in two segments. The first one, I removed most of the sand as I was washing it to process. The second one was the one I processed with the cement mixer and that method didn’t remove as much sand as it used less water which resulted in a thicker slurry and less settling. I mixed these two together and it’s still a bit grittier than I like but I think I can still use it. Glaze fit could potentially be affected by the extra sand but that will be tested.

I am a bit worried as the extra sand/silt is making it thixotropic and adding Neph Sye as a body flux usually makes things worse. If I had been thinking when I mixed up these bars, I would have used the Mahavir Feldspar I have sitting instead of the Neph Sye. I just grabbed the Neph Sye out of habit.

The bowl was thrown with the 14% batch it it threw quite well. Better than I had expected. I’ll need to throw a mug and handle it to see how things really work.


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