Slip & glaze
Almost more than clay itself, it was the plain raw slips and glazes and the creative potential they offered, along with their transformation in firing, which first really captured my imagination for the subject. Submerging a full armful of the gorgeous stuff is only the beginning; thick, creamy and smooth, the slip is stirred and paddled to ensure an even liquid suspension before it’s use. In common with generations of artistic endeavour before us, we find the development of these materials in our hands, lends us the freedom to run with new ideas.
My finest enjoyment in using slip is in it’s wet state. Finger-wiping and wet scragfitto, marks and motifs evolve to describe and punctuate the undulating forms of different pots. A certain immediacy of process as well as repetition, provokes fresh ideas.
Raw-glazes often incorporate various home-dug or collected materials, wood ashes, surface clays and granite dust for example. I can only explain this curiosity for found ingredients as something primal. It is time-consuming work that requires persistence to achieve satisfying results. The outcome however, is immensely satisfying and unique. Despite the frequently simple composition of recipe, these slips and glazes, in combination with the process of wood-fired salt-glaze, underpin a limitless wealth of creative possibilities and sophisticated fired surfaces.
Clay derived slips are made up from powdered raw ingredients. The simplest recipes are composed from as few as two materials. Different ball clays, china clays and porcelain are combined in different proportions for different results. Small percentages of colouring oxide and silicas such as nepheline syenite and potash feldspar are also sometimes added to alter surface quality
Mug dunking in ball clay/china clay slip
Emerging slip dipped
Slip dip
Espresso mug, excess slip is removed from the rim
Slip thickness is wiped away from the inside of some handles. Excess moisture absorption risks the handle failing
Ladling shino liner into raw mug
Raw-glazing, shino liner
Raw-glazing: Many pots are glazed only on the inside, where the sodium vapour alone is relied upon to glaze the decorative clay slips during firing. Here the outside is being ash-glazed. The sodium during the firing will provide serendipitous fluxing to this glaze, altering it’s colour and appearance. The enriched surface becomes more fluid and accentuates the slip decoration underneath
I am a prolific note taker! Many new variations and combinations of slips and glazes are trialled in any one salt-firing. These notes are a useful reference post-firing and then as I begin the next new batch of work
Insides are glazed and outsides are decorated over a number of hours or often a couple of days when multiple layers of slip are required.
Decorated mugs await salt-firing
A second dip in very thin blue/black slip adds a different colour range and will alter the way that the salt-firing picks up textural details in decoration and on edges. This slip is also wonderful to draw back through, with a rubber paint shaper for example, exposing the porcelain slip underneath
Jug detail: bone dry and awaiting firing. Wet scragfitto – slipped and part-dipped in ash glaze
Sideplates await firing. Finger-wiped, scragfitto and brushed slip decoration
Candleholders, slip decorated