Ceramics Fly-Ash Glazing
Lucie Ponard
Graduate 2021, Master Industrial Design

What did you find out with this research?
How to reuse industrial waste (steel slag, coal ash, pieces of brick) gathered from Westduinpark as pigments for glazing ceramics. Mostly, I was introducing pigments in different proportions to a base glaze, to create a palette of colours.

If anything went wrong along the way, what did you do?
So many things went wrong! Sometimes, I would open the kiln and all the samples were disappointing. I would then add another layer of glaze and fire them again, if I had space in the next kiln.

Pigments: pieces of brick, steel slag, coal ash (smashed in various sizes of grains).
Texture elements: sand, pieces of shells (smashed in various sizes of grains).
Glazing bases: transparent base for 1100° and 1200°, white base for 1100° and 1200°. Clay body (has to withstand the temperature you are firing at).

Ceramic kilns (temperatures: 1100° and 1230°), press, sieve, very precise weighing scale that measures 0,1g. (I bought mine at a cooking shop), glazing brush

KABK Ceramics
KABK Metal

1. Smash rocks using press and sieve them into very fine powders.
2. Bake clay tile of about 5 x10cm. For this you will need 10g base + 3% 6% 9% 12% 18% of pigments. Mix together, add water, and apply with brush.
3. Based on these first experiments, more or less pigments can be added for the next one. Write a number on the first batch of experiment tiles, to remember what colours correspond to what percentages.
4. Pro-tip: Clay shrinks, so if tile is 5x10 when unbaked, it will be smaller once baked.
5. Pro-tip: The clay that you use should have a similar firing temperature to the glaze (otherwise the whole tile will melt completely.)

Health and Safety Precautions:
Always use a mask when sieving, because very thin powder is in the air. Since my pigments were a bit unknown, I also used a mask and gloves when applying the glaze.

This recipe is part of Touching: A Research Method in Art and Design, an exhibition curated by architect and KABK tutor Laura van Santen, featuring the materials and research of students, tutors and workshop instructors from the KABK.

More information on the display, all samples and recipes can be found here.