For the last couple of years I’ve been trying to work more with local, hand-gathered materials, to reduce my reliance on materials that come from far away through resource-intensive processes, and which have major impacts on local ecologies. Most of the clay near me in BC is low-fire/earthenware, which makes sense given the brickmaking industry in the lower mainland, Vancouver Island, and the Gulf Islands.
With some help from my friend’s kiddos, I dug out a small amount of exposed clay in Ladysmith, processed it, and prepared some test bars to figure out its optimal firing temp.
Decided to try dry processing- completely dry out the clay and then crush it into small pieces. Dry clay slakes down in water more easily which means it will make a more uniform mixture with no lumps, as opposed to moist clay which is resistant to taking on more water and mixing evenly. Having now wet processed clay, I’d say it was easier than dry-processing.
After drying the wets, wet the dries. Added water to the dry clay and let it slake down into a runny solution. It needs to be runny enough to pour through a fine mesh to get out all the stones, twigs, and other organics. I saved the sand in case the clay needed some grog.
Now to dry the wets by leaving the bucket to stand for a few says and siphoning off the clear water on top after the clay particles sink to the bottom. Then I poured the remaining mixture into an old pillowcase and hung it to air dry, moving it to rest on a plaster bat after a few days.
I made some test bars and some pinch pots to fire at different temperatures. From left to right, top to bottom:
Bottom left: unfired
Second from bottom left: cone 06
Second from top left: cone 04
Top left: cone 5
Bottom right: cone 06
Middle right: cone 6
Top right: cone 10
The ideal temperature for a clay body is probably somewhere around cone 2, but it could make a nice cone 10 glaze!