The local clay I’ve been digging around BC is all low-fire clay; cone 1 is probably its ideal temperature, and it’s completely melted at cone 10. As the studio I work at regularly fires to cone 10, I decided to do some glaze tests with this clay.

I decided to try a very simple ash glaze, combining the local clay with wood ash, reasoning that the local clay would be similar enough to redart, and with a line blend I could try and figure out a good ratio. I posted on my local buy nothing group to see if anyone had ash in their fireplace or fire pit that I could collect, and someone responded! However I’m pretty sure they weren’t exclusively firing wood in their fireplace… there was definitely remnants of combustible trash and nails, so in retrospect I shouldn’t have had high hopes for this experiment!

I tested the glazes on both a light and a dark clay- Plainsman H550 grey stoneware and Plainsman H440 red stoneware. And I threw in an extra test of 100% clay just to see if there was a difference in the look of Ladysmith clay vs Port Moody clay, and there was! The Ladysmith clay is darker, slightly purplish and with a metalic sheen. The Port Moody clay is more red and chocolatey with no metalic quality.

The tests with higher ratios of clay worked well- I think this clay would be great as a glaze just by itself. But the higher the ratio of wood ash, the less the tests melted. They might need additional flux, but it would probably be worth trying with a better source of wood ash, maybe from the wood kiln at the Shadbolt. There were some interesting dark speckles throughout the tests with higher ash content, and who even knows what they were! The mystery ash probably contains too many variables, and ash is variable enough on its own, given that every tree or plant is going to have a different chemical makeup that will affect the glaze chemistry. It was a neat experiment to get me started though!