INTRODUCTION:
“Give us one miracle and we’ll explain the rest…” Terence McKenna
You are all familiar with the periodic table which lists all the elements known to mankind, elements which, in essence, make up the world we live in. Scientists tell us that aside from Hydrogen, Helium and Lithium, which were created as a result of the Big Bang most elements originated in the nuclear furnaces of dying stars. Gigantic stars, also known as Super Novas, have such high internal pressure and temperature (approx. 15million degree Celcius) that they are capable of fusing Hydrogen into Helium. In turn two Helium nuclei would fuse together to create the nucleus of a new element called Beryllium. When Beryllium fuses with Helium you get Carbon and when Carbon fuses with Helium you have Oxygen.. so on an so forth - you get the idea. When super nova stars reach the end of their life cycle they spew these elements into space where over time they can combine and cluster into celestial bodies like the Earth and the planets and moons in our Solar system.
Some of the most abundant elements that make up the Earth’s crust are Oxygen, Silica, Aluminum, Iron, Calcium, Sodium, Potassium and Magnesium. These elements alongside the ones you will see in “the periodic table for potters” (image attached) are all important part of the creative journey of any potter who wants to develop glazes. Up to now 118 elements have been discovered but as potters we are only concerned with 23.
It’s important to highlight that the majority of these 23 elements are not used in their pure form when mixing up glazes because, on our planet, under atmospheric conditions, they combine with other elements such as hydrogen, oxygen and carbon. It would be incredibly difficult and expensive for the potter to source the “ingredients” of a glaze recipe from pure raw materials although theoretically it is possible. Most materials, with the exception of a few rare, radioactive and precious metals, are mined on a mass scale in a highly purified form and are widely available at a relatively affordable price. To navigate the chemical composition of these purified materials, a basic understanding of their names, active compounds and the role they play in glaze chemistry is necessary.
Glaze recipes
Ceramic glaze recipes are made up of three parts: glass former, stabiliser and flux. These will form your base recipe or base glaze. There are further raw materials which may be included, for example to alter the opacity, colour and behaviour of a glaze. These materials are referred to as “additions”
To help you understand what a glaze recipe looks like and to highlight why it is important to understand the materials involved, we will take Altar’s no.53 glaze as a starting point for our exploration. You may recall that this is a purple dipping glaze.
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