What it’s all about

In ceramics, we generally conceive of clay and glaze as two distinct categories. Yet glazes and claybodies contain many of the same materials in differing amounts that vary relative to their performance criteria. Conventionally, clays hold their form and glazes thinly coat their surface. The Hot Alchemy project aims to create a spectrum of materials that compositionally range between clay and glaze, a zone with less distinct properties, where forms and surfaces might meld, move or take shape on their own. The word alchemy conjures the seemingly magical process of material transformation and it is in this spirit that I, together with a group of research assistants, undertook this exploration for unusual ceramic materials. Rather than beginning with specific calculations, we began with materials we knew – recipes of claybodies and glazes that had some desirable qualities and morph them into new materials that could behave differently. We set up a few guiding principles and then proceeded to make tests that left plenty of room for the delight of discovery in the heat of the kiln.

Claybodies and glazes basically contain the same ingredients: clay and flux in wildly different amounts. By varying the proportion of clay to flux, many of the so-called “faults” happen such as blistering, crawling, pinholing or running. While these results are undesirable for utilitarian ceramics (hence the term fault) these less usual material behaviors can be of great interest for ceramic sculpture. Our desire to mine the potential of this ‘fault’ zone led to the investigations that make up the Hot Alchemy project. In numerous ways, we searched for clays that would soften, deform, melt and become shiny as well as glazes that would move, drip, bubble and thicken into texture. The process of discovery was guided by our interests while remaining open to all results and flexible in directing the exploration. We felt that if we were certain about what we were are looking for, we may not be as open to the possibilities that would arise in the testing process.

The work proceeded by reformulating clays with more glaze materials to encourage their movement, and conversely, by adding clay components to glaze in order to help them take shape. We began with testing out blends of fluxing materials to gauge their melting range then proceeded to blend together existing recipes of clay and glaze. We modified these blends to achieve a balance between workability and meltability, observing the physical characteristics while adjusting proportions. Starting broad then narrowing, we mixed and altered recipes in increments that were quick and easy to do in the glaze lab through volumetric blending. This was a good way to initially obtain quick results that allowed us to see trends in characteristics. The fast results fostered enthusiasm for further testing and accelerated progress. We made choices based on the quality of the results as well as the desirability and feasibility of using them.

The project developed five main areas of investigation based on our interests:

• FLUX BLENDS • CLAY / GLAZE BLENDS • FUSED SILICA GLAZES • DRY GLAZEBODIES • SLOW MOVING GLAZEBODIES

The final step in our testing process included calculating batch formulas and retesting results to ensure repeatability. These calculations included the Unity Molecular Formula which offers a way to compare materials based on their composition. We experimented materially first and subsequently calculated their chemical formulas because workability was paramount to the process. The workability of a material is an actual physical reality and cannot always be predicted theoretically through calculation. Some clays like bone china became more plastic when blended with certain glazes. Some glazes without alteration were plastic enough to form. Glaze calculation theory did help to to create some working guidelines for future investigations. Decisions were made about what materials to pursue and what characteristics to develop based on what we would want to incorporate into our work. I loved the stark white of the bone china but I didn’t like its chalkiness or its lack of plasticity. We mixed various glazes into bone china and found some blends that increased plasticity while gently fluxing it, with a smooth shiny look akin to tooth enamel.

Testing these materials required an unconventional approach in order to capture the unusual properties of the materials we were making. While flat test tiles gave no indication of a material’s movement, even when propped during firing, recording them simply as a surface coating, we developed a few tests that indicated how materials could shift during firing. The easiest and quickest test is rolling a ball then flattening it into a button shape and placing it on a flat test tile. These quick buttons revealed both fluxing qualities and indicated basic plasticity. When a material appeared promising, we would roll it into a coil then bend it into a standing arc, and we would press it in a small rectangular mold. These arc and rectangular shapes either held clear lines or softened and deformed. It was easy to compare them to their original form and to other tests. For drippy materials, we made sticks or flat slabs that were dried and set on a U shaped channel that allowed space for gravity to work on the material. Alternately, we laid small slabs supported by an upside-down U shape like a half donut where the middle was supported and the drips wrapped around the form then dropped to the flat test tiles below.  Since these materials are prone to melting, the flat tiles are to catch any dripping clay or glaze.

Aside from the malleability inherent to the newly formulated glazebodies, their moisture content was a significant factor contributing to their workability. Certain glazes could be simply dried out and treated like clay: rolled into a ball, made into a noodle, defloculated and cast. We tried extrusion which required more plasticity than one might imagine. Some materials became thixotropic when pressure was applied and therefore could not be extruded. We mostly worked with hand forming and press molding to take full advantage of even small amounts of plasticity in the materials and some of these will next be tried in a 3D printer.

It is interesting to think outside of conventional categories by combining and treating materials in multiple ways that in turn lead to new ways of working. When one research assistant explained the project to one of my colleagues, she remarked “Oh! You are making cones!” In a sense we are making cones not in the shape of cones but as materials formulated to melt at different rates at certain temperatures. The Hot Alchemy project benefited from the input of the various artists who worked as research assistants on the project, taking it in multiple directions simultaneously. We now have the beginnings of a growing library of tested materials that stretch the traditional boundaries of clay and glaze.

The Hot Alchemy project was made possible through funding from the FRQSC – Fonds de Recherche de Quebec Société et Culture and the efforts of the following students from Concordia University: Mel Arsenault, Erin Berry, Markus Denil, Rachelle Marcoux, Danielle Oostergo, Manon Pierquet, Sarah-Jeanne Riberdy St Pierre, Michelle Sayer and Laurence Veri. Check them out on the Alchemists page!