K3 instructions

A collaborative research project on eutectic glazes across geological origins

If you arrive at this page through a QR-invitation: 

WELCOME and thank you for accepting my invitation and test-tile. This page gives more information and a Step-by-step plan to make a K3 test.  (by the way if you missed it: K3 is a simple-recipe-glaze of three ingredients: Kaolin, Whiting and Quartz, each one third in weight.)

For this research I am trying to answer the following question: How does K3 respond when the kaolin comes from a different part of the world? The chemical composition of kaolin varies fundamentally by geological origin: primary granitic kaolins (Cornwall, Germany, Jingdezhen) behave very differently from sedimentary kaolins (Georgia, Brazil, Ukraine) or tropical weathering kaolins (Ethiopia, India, Nigeria). The same recipe may produce a completely different surface depending on where the earth came from.  And how does the kaolin influence the melting point?

More technical information about Kaolin and the ‘other K’s  you can find here.

step-by-step plan

Source a local kaolin. Use a kaolin that is commercially available in your region — ideally one commonly used by potters or ceramic artists where you work. Please note the brand name, origin of deposit, and any technical specifications (XRF/XRD data if available). Do not substitute with ball clay, bentonite, or other clays.

Mix the K3 recipe. Combine exactly equal weights of three dry materials:

INGREDIENT 1

33.33% Silica (quartz)

INGREDIENT 2

33.33% Whiting (CaCO₃)

INGREDIENT 3

33.33% Your local kaolin

Minimum 100g recommended: you can test 10 tiles of 10x10cm with this amount.

Mix dry, then add water to brushing consistency. 

Sieve through 120 mesh if possible.

You can add one drop of a defflocculant and one drop of a cmc-solution to make it more brushable. 

Brush 3 layers on biscuit-fired tiles and fire at 1170°C. 

If it is not melting: fire 10° higher and so on, till you have find the lowest melting point. It would be great if you can use for every firing another tile. If you have find the melting temperature: brush the tile I have given/sent you. It has a little hole in the middle for my presentation, please keep this open ;-) 

The firing schedule I use in my small electric test kiln:

My firing schedule: 150°C/h to 1080°, 60°C/h to 1180°C, 10' soaking time and 200°C/h cooling to 950°C and than natural cooling.

The tile may lay down during firing. 

If you fire in gas- or wood-kiln I suppose it is not possible to fire the whole kiln to such a low temperature because the rest of your glazes will not melt. Or the temperature is maybe not that exact? You can still help me with my project.  Can you put a Cone-set or a PTCR-ring next to the tile and fire it to your normal Temperature? It would be great to see how your K3 melts in your kiln. Let me know your firing schedule and atmosphere.

For this comparison of the melting-behaviour of Kaolin I prefer not to use colour-additives. But you can always do some colour tests. I discovered the glaze reacts on very low amounts of colourants. You only need a tiny bit of chromium (only 0,04%) and tin (2,5%) and the glaze gets a very nice pink. You can find some colour inspiration on my Glazy.org page.

One of the advantages of using a glaze-mixture close to the eutectic-melting-point is its hardness and durability.  Also you can use this recipe to add other ingredients to find the texture or colour response which you prefer.

E-mail me for an QR-code to resent the tile (for free) to Belgium. 

Before sending, please photograph the tile clearly (natural daylight preferred). 

Add in your correspondence following information:

• Your name and location (country / region)

• Kaolin brand and geological origin if known

• Firing temperature and atmosphere

• Any observations: did it melt? crawl? stay matte?

• May I include your name in the artwork and on the research website? if yes:  You will be mentioned in my research!

The returned tiles will be assembled into a collaborative artwork and exhibited. Each tile becomes a small geological portrait — the earth of one place, transformed by fire into a surface that tells the story of its origin.

You can follow the growing collection of K3 glaze tests at glazy.org/K3library, where I document the chemistry and results of every test in my library.

Thank you very much for your collaboration.