I never would have guessed, from the amount of sand in this body, that it would craze. Never in my wildest dreams and yet, here we are.
This is my latest dug clay and one I will be working with more soon. It seems to be low enough in iron to avoid cementing but still have enough to give a nice red color. I dug it from a ditch right beside my house. With the sand removed the drying shrinkage was a crazy 15% (just drying, total was 22%). I added some of the fine sand back in and it’s still fairly high at around 9% but I’ve had no problems with things cracking thus far. It’s a very nice fired color. The glaze is denim, it has a bit higher expansion than some of my other glazes but should be well within range of a stoneware glaze. Glazy.org puts the expansion at 7.3. It fits my reclaim well.
The fired porosity of this body, at cone 6, is 2.9% which is higher than I’d really like (I shoot for 1.5%). Adding a bit more neph sye to the mix will perhaps cause enough shrinkage to eliminate the crazing. I’ll just have to test it and see. If not, I’ll use lower expansion glazes with this one and/or add some of my silt to increase expansion.
Do your testing and know your materials.
Handcrafted Functional Pottery from Native Clays and Materials
