Research
A collaborative research project on eutectic glazes across geological origins
The K3 glaze project is a long term research project of Jeannine Vrins who lives and works in Belgium, Europe: “I started with a fascination for the ‘simple’ glaze recipe: one third of kaolin, on third of quartz and one third of whiting. In my language the three ingredients start with a K so thats why I call it K3. “ (K3 is also a Girls Band in Belgium ;-)
This research started with the wondering: why is this melting on 1180°C. Inspired by the research of Anton Reijnders (EKWC, NL, The Ceramic Process) about Eutectics, Jeannine started to test the K3 glaze in different countries. Because the kaolin differs on every continent the eutectic temperature differs. (Quartz and Whiting have a more consistent chemical analyses world wide than kaolin but can differ also… more technical info you can find here).
Ceramicists from over the world are asked to do the same test with ’their K3’:
The principle of ‘why this glaze melts’ is because of eutectics: the Melting Point of the mixture is lower than the Melting Point of each of the ingredients.
The ternary eutectic point of the system of calcium oxide CaO (MP 2500°C), alumina Al2O3 (MP 2020°C) and silica SiO2 (MP 1710°C) starts melting at 1160°C.
The composition at this lowest-melting point is:
Silica: 62 wt.%
Calcium Oxide: 23.25 wt.%
Alumina: 14.75 wt.%
Because the raw materials (crushed rock) exhibit variable elemental compositions and phase ratios our eutectic glaze mixture will never get perfectly to those weight-%. Our ingredients are not pure and differ from where they are mined on the world. In Belgium we use a Polwhite Kaolin B from Imerys which has a low Al2O3 and some Na2O and K2O in it. That’s why the Belgian K3 can melt at 1180°. When testing in UK the K3 melted just above 1220°C and in Denmark it was melting around 1200°C. Still pretty low for a glossy transparent without addition of any frits.
The used firing schedule: 150°C/h to 1080°, 60°C/h to 1180°C, 10' soaking time and 200°C/h cooling to 950°C. I add 80% of water with some deflocculant, bentonite and cmc in it, a rheological mixture which makes it brushable and suspended.
On a tile of 10 square centimetres is used 10 grams of glaze. It is brushed in 3 layers in different directions on a biscuit fired tile.
If you want to collaborate to this project? Send an e-mail jeannine.vrins@pxl.be
We will send you a tile and the instructions.
All information from the research will be shared. The results will be used in my PhD, art-research.
You can find more test instructions here.
I do not renew articles of this website every week but I try to post my latest tests, shapes, works on Instagram. I invite you to follow me:
