SLIP-CASTING a ceramic forming technique WHAT IS SLIP-CASTING? - PowerPoint PPT Presentation

SLIP-CASTING a ceramic forming technique

WHAT IS SLIP-CASTING? http://www.sightunseen.com/2012/06/josh-bitellis-forfars-bakery-and-roadworkers-projects/ http://www.joshbitelli.co.uk/ Slip-casting is a technique for small-scale production runs, especially for shapes not easily made on a wheel. It is the process of filling a plaster mould with casting slip (liquid clay) in order to create a clay object. Advantages • Ideal for producing hollow ware • Complex forms can easily be achieved • Does not require much finishing (usually only fettling) • Efficient use of material • Slip is fairly inexpensive • Lets itself well to small-scale production runs or limited editions Disadvantages • Labour intensive • Slow production rate • Limited control over tolerances • Moulds may be heavy to handle • Large scale production requires many moulds, which them- selves require storage

SLIP-CASTING MANIFESTO You can’t learn “ceramics” in a week Come prepared You are going to get dirty Don’t be scared of making mistakes Don’t come expecting to learn everything Have a design in mind before starting and Don’t be scared of getting dirty. Use your You are probably not going to get it right the there is to learn straight away. Take baby preferably some tools hands, get familiar with the material first time. Experiment as much as possible as steps and focus on one aspect at the time the best results often come from experimenting and making mistakes. Experience comes with time

PROTOTYPE MDF Clay Blue foam Other Easy to work and tool with, more durable. A model can easily be made with clay. It is This is a material that is relatively easy to A model may also consist of very soft Prototype is safe and intact, great for preferable to allow the model to dry to the handle and very light. It is quite expensive so materials such as mattress foam or textiles. achieving sharp, transitional lines and edges. leatherhard stage before making the mould. use it reasonably. While moulding it is very However, during the construction of the Laminating together with wood glue might You should preferably use a clay body that delicate and can get scratches easily so you mould, deformation may occur due to the take a long to dry etc. but once it’s glued, it’s is similar in color to the work after firing it to have to handle it with care. Otherwise it is weight exerted by the mould. The material avoid traces of clay of a different color in the ideal for more organic shapes that can be can become compressed, resulting in firm and stable. final piece. This technique is not very exact in hard to obtain with wood. staggered mould seams. measurements so it’s ideal if you want a free hand product.

PLANNING MOULD SECTIONS Factors to take into consideration • Each undercut makes another mould section necessary (a curve in the form which makes it impossible to remove the mould section without damaging the form) • Manageability of the mould is another factor determining the placement of mould sections. • The weight of each mould section and of the entire mould • The way the mould is filled and emptied • How to hold together the different sections together (straps, tape or wires) • Where to position your pouring hole • How the mould is going to stand; its stability and strength (especially when doing One piece Two piece or Multi-pieced multi-sectioned moulds)

MAKING A CASTING MOULD Use of cottes (device that holds the liquid plaster around the mould) Free hand • Faster to make • Longer to make • Less waste of material • Use of more material • Irregular mould • More refined look • May not be self-standing • Stable

CASTING The slip is poured into a plaster mould, which The slip is allowed to sit in the mould until a The mould is then turned upside down and The cast piece is then removed from the absorbs the water leaving a layer of hard, desired thickness has been built up any remaining slip is poured out mould, fettled (trimmed neatly) and allowed to leathery ceramic dry before firing

LEARNING FROM MISTAKES

BENJAMIN HUBERT - “Chimney Lights” http://www.hayonstudio.com Benjamin Hubert conducts materials driven industrial design projects where the starting point of the process is the material or production technique. The studio challenges the everyday application of materials, traditions of construction and ideas of context. The Chimney lights are produced using a technique known as slip- casting (liquid clay poured into plaster moulds) – they are cast with a white earthenware clay. After casting they are hand painted with a terracotta slip which has an addition of 25% sand – the painting process takes place on a potter’s wheel. They are then glazed on the inside with a white tin glaze and kiln fired. Each lamp has its own unique character with a textured exterior finish in contrast to a gloss white glazed interior.

VALISSA BUTTERWORTH - “The Mod Collective” http://www.craft.org.au/See/window-space/the-mod-collective/ http://themodcollective.com.au/ Designed and made in Victoria, Valissa’s manufacturing process is a seamless combination of cutting edge technology and traditional craft practice that enables innovative investigations into non-conventional porcelain production methods and a unique product outcome. Each concept is developed using Design software then printed on 3D printers in various mediums including plaster and plastic. Prototypes are moulded using a combination of silicones and plaster to obtain the final moulds for slip casting. The creation of these moulds is a longer and more involved process than simple plaster mould making as the resulting moulds retain the intricate details the 3D printing process leaves in each prototype. These markings serve as a conscious and permanent reminder of the technology employed in their creation. The next phase is traditional slip casting using coloured porcelain slip. Pigments are added at the liquid stage so the colour permeates each piece entirely, resulting in a depth of colour not able to be achieved by normal glazing. The pieces are then clear gloss glazed on both the inside surface and lip to retain functionality and fired to a vitreous temperature rendering them microwave and dishwasher safe.

JOSH BITELLI - “Forfars Bakery Trophies” http://www.sightunseen.com/2012/06/josh-bitellis-forfars-bakery-and-roadworkers-projects/ http://www.joshbitelli.co.uk/ Bitelli’s practice centres around the translation of research gathered from a given site into crafted objects. The history or provenance of a place becomes the foundations for an experimental de-coding, a type of story telling that narrates how things work, the people involved and the materiality of things. Bitelli’s slip-cast Trophies not only pay homage to the 75th anniversary of the Forfars Bakery in Brighton, they also highlight the industrial machinery and mass-production processes that have allowed the bakery to remain competitive despite the changing nature of the bread business. Taking a more hands-on approach, the designer borrowed some of Forfars’s product to create large bread molds into which he poured semi-porcelain slip, performing thousands of tests with different types of loaves. “The slip had to be left for around six weeks to dry, and in this time, the surrounding bread grew some really amazing mold, I think because of the oxides and stains in the slip body,” he said. “I tried to copy this color palette in the finished vases.” Bitelli was particularly proud of proving it was possible “to hack even the most standardized and safety-checked industries for the production of artisanal and crafted objects”

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