I have used seaweed in my work for some time, laying it directly onto the surface of pots during firing. For years I have been meaning to test its use as a glaze component. Wood ash is commonly used in glazes as is other organic matter, I have only ever seen one reference to seaweed ash. It took a sack full of seaweed to make a handful of ash, enough for a few tests.
It is so rewarding using raw materials from my surroundings. I am often struck by the subtlety of the materials and how they exude there location. These tests with seaweed ash definitely have a sense of the atlantic about them. Every raw material that I collect has a unique quality, a strength of character that prevails through the extreme metamorphic processes of the firing.
I left a Votive Jar among the kelps and Worts, which have been such a rich and important resource for thousands of years.