Casting ripples in the sand, in order to create a glass version, has been a long held ambition. To capture a unique moment in time in a textural form. A cake tin proved a handy test-mould without using up too much raw material.
The basic recipe:·
50% Plaster
50% Flint (or substitute)
Water (one part water in ml for every 1.5 volume of dry mould material in kgs)
Mix til it goes creamy, and pour.
Was really chuffed to find that substituting the flint (ground silica) with used bat wash (shelf primer) seems to work well. Shelf primer is half alumina and half china clay so has good refractory qualities and is a regular part of the studio waste stream.
If the firing goes well, next time I will use a larger rectangular form and be ready for the low tide!