-SQA-SCOTTISH QUALIFICATIONS AUTHORITY. Hanover House 24 Douglas Street GLASGOW G2 7NQ NATIONAL CERTIFICATE MODULE DESCRIPTOR

Transcription

1 -SQA-SCOTTISH QUALIFICATIONS AUTHORITY Hanover House 24 Douglas Street GLASGOW G2 7NQ NATIONAL CERTIFICATE MODULE DESCRIPTOR -Module Number Session Superclass- JR -Title- CERAMICS: MOULD MAKING AND SLIP CASTING (x 2) -DESCRIPTION- Purpose This module is designed to introduce the student to slip casting and to develop his/her skills in mould making by producing a multi-piece mould. It will be of interest to students wishing to learn the skills of the main industrial production method used in potteries as well as to those with a general interest in ceramics. Preferred Ceramics: Introduction to Press Mould Entry Level Making and Decoration and Ceramics: Introduction to the Wheel. Outcomes The student should: 1. design and make a model suitable for production by slip casting; 2. prepare the model for casting in plaster; 3. produce a multi-piece slip mould; 4. produce slip cast ware; 5. use a range of decorative and glazing techniques; 6. load kilns for bisque and glaze firing; 7. demonstrate a knowledge of glaze composition. Assessment Procedures Acceptable performance in this module will be satisfactory achievement of all the Performance Criteria specified for each Outcome.

2 The following abbreviations are used below: PC Performance Criteria Instrument of Assessment Note: The Outcomes and PCs are mandatory and cannot be altered. The may be altered by arrangement with SQA. (Where a range of performance is indicated, this should be regarded as an extension of the PCs and is therefore mandatory.) OUTCOME 1 DESIGN AND MAKE A MODEL SUITABLE FOR PRODUCTION BY SLIP CASTING PCs (a) Preliminary drawings, plans and sections for the model: (i) (ii) (iii) include the sprew for pouring and draining the mould; show awareness of the necessity for the model to have draw; indicate the parting lines of the mould and the order and direction of the removal of the mould sections. (b) (c) The solid clay model with a footring, shows good control of the throwing and turning process. The solid clay tapered sprew is thrown and turned so that it fits the model leaving a rim of suitable thickness for the size and function of the pot. Assignment The student will be given a specific brief to design and plan a wheel thrown form with footring that can be cast as a multi-piece mould. The mould may be a 2, 3 or 4 piece mould. The original solid model may include a handle, spout, modelling, incised or impressed decoration. on all Performance Criteria being met. OUTCOME 2 PREPARE THE MODEL FOR CASTING IN PLASTER PCs (a) Plaster shim is cast on glass and is of a suitable size and thickness for the size of mould and has a smooth finish. (b) End bats or shims are trimmed and filed neatly so that they will produce a mould of suitable thickness and shape with regard to the size and shape of the model

3 (c) (d) (e) The parting line on the model is marked accurately so that the mould will part without damaging the casting. Shim is trimmed accurately so that it fits closely against the model. The model, sprew and shim are set up accurately and firmly supported with clay to permit accurate casting. test his/her ability to prepare the model for casting. The model may be a 2, 3 or 4 piece mould: 3 or 4 piece moulds will require end bats and a base plug. The tutor will record the student's compliance with the relevant Performance Criteria on a suitably constructed observation checklist. on all the Performance Criteria being met. OUTCOME 3 PRODUCE A MULTI-PIECE SLIP MOULD PCs (a) All plaster surfaces are adequately soaped to prevent adhesion. (b) Lino coddle is securely attached so that the mould does not leak when casting. (c) Plaster is carefully added to water, slaked and stirred to produce a smooth air and lump free mix. (d) The plaster is poured steadily and the mould gently vibrated to dislodge air bubbles. (e) The coddle is removed when the plaster is at the cheese hard state permitting successful screeding, flush with the end bats or shim, to produce a neat exterior shape and finish. (f) When set, the cast surface is tidied, location notches are cut and the surface soaped so that remaining sections of the mould are free of defects, will locate accurately and will separate. (g) The outside edges of the completed mould are trimmed producing a well finished, easily cleaned mould. test his/her ability to cast a multi-piece mould. The mould may be a 2, 3 or 4 piece mould. The tutor will record the student's compliance with the relevant Performance Criteria on a suitably constructed checklist

4 on all the Performance Criteria being met. OUTCOME 4 PRODUCE SLIP CAST WARE PCs (a) Knowledge of the effects the chemical additions make to the casting slip is accurate so that defects caused by incorrectly prepared slip can be identified and rectified. (b) Casting slip is adequately stirred and sieved to a homogeneous consistency and is free of lumps. (c) (d) (e) (f) (g) Slip is poured steadily to avoid wreathing. The mould is correctly drained to ensure that clay does not run back and drips do not set on the base of the ware. The casting is of an appropriate thickness with regard to the size of the ware. The casting is removed from the mould without damage. The casting is neatly fettled. Short Answer Questions Performance Criterion (a) The student will be presented with eight short answer questions to test his/her knowledge of the effects that addition of deflocculant and alkali has on casting slip and defects caused by incorrectly prepared slip. The questions should be allocated as follows: 1. the additions made; 2 2. the effects the additions have on the clay; 3 3. defects and remedies. 3 Performance Criteria (b) - (g) test his/her ability to produce and fettle at least four slip castings. on all the Performance Criteria being met. This will be demonstrated by the student answering all eight questions correctly and producing slipcast ware

5 OUTCOMES 5 USE A RANGE OF DECORATIVE AND GLAZING TECHNIQUES PCs (a) Preliminary designs demonstrate: (i) (ii) (iii) an awareness of the range of decorative techniques available; an understanding of design elements such as proportion, balance, symmetry/ asymmetry, pattern, rhythm and colour balance; appropriate use of drawing materials to highlight the decorative technique. (b) (c) (d) (e) The selection of designs is appropriate for the decorative techniques used. The application of decoration is neat and shows control of the technique used. The application of glaze is even, free of defects and of appropriate thickness for the type of glaze used. The preparation of the glazed ware for firing is correct with regard to cleaning surplus glaze from base of ware, and checking for pinholing and cracks on surface in raw glaze. 1. Performance Criterion (a) demonstrate his/her awareness of the range of decorative techniques available. The student will produce six preliminary designs, each demonstrating a knowledge of a different decorative technique. The designs may be prepared on paper, bisque tiles or raw clay with drawing materials appropriate to the medium used. 2. Performance Criterion (b) - (e) demonstrate his/her ability to use a variety of decorative and glazing techniques. The student will select 3 of the preliminary designs prepared for Performance Criterion (a) and use them to decorate at least four slip cast pots. He/she should use at least 3 different techniques but 2 or more may be combined in a single pot. on all Performance Criteria being met

6 OUTCOME 6 LOAD KILNS FOR BISQUE AND GLAZE FIRING PCs (a) Pieces are identified as being in the correct state for bisque firing. (b) Work is loaded into the kiln without damage when stacking or boxing. (c) Pieces are positioned correctly with regard to burners or elements. (d) The glazed ware is checked to ensure that the base is adequately cleaned to prevent damage to bats. (e) Stilts, saddles or kiln placing powder is used appropriately to ensure that glazed ware does not stick to bats. (f) The placing of glazed ware in the kiln is correct with regard to spacing between pots. The student's workshop practice in relation to the loading of kilns will be observed to ensure that it meets Performance Criteria. The tutor will record the student's performance on a suitably constructed checklist. Satisfactory achievement of the Outcome will be demonstrated by all Performance Criteria being met. OUTCOME 7 DEMONSTRATE A KNOWLEDGE OF GLAZE COMPOSITION PCs (a) Knowledge of glaze composition is accurate with regard to the types of ingredients and their function. (b) Knowledge of the use of metallic oxides is accurate with regard to the colours produced. (c) Knowledge of common glaze defects is accurate with regard to the causes and prevention of defects. (d) Knowledge of the effect of the kiln atmosphere and the firing cycle on glaze is correct. Short Answer Questions The student will be presented with 12 short answer questions to test his/her knowledge of glaze composition. The questions will be allocated to ensure that all Performance Criteria for the Outcome are covered. on all Performance Criteria being met. This will be demonstrated by the student answering 9 questions correctly

7 The following sections of the descriptor are offered as guidance. They are not mandatory. CONTENT/CONTEXT Corresponding to Outcomes 1-7: 1. Drawing, plans, cross sections. The draw or draft required in the mould. Parting lines to divide the mould into sections. The need for a sprew or spare, end bats and base plug. Throwing, turning techniques. Making handles, plaster moulds for impressed decoration. Cutting incised decoration. 2. Plaster: mixing, slaking, stirring, pouring. Cutting and filing plaster. Marking parting lines. Assembling plaster shim, end bats, base plug, sprew accurately and securely. 3. Soaping: coddles; fixing securely. Mixing and pouring plaster, screeding when cheese hard. Cutting location notches. Trimming edges, drying moulds without warping. 4. Casting slip: deflocculant, alkali, reduced water content, flabbiness, brittleness. Casting defects: wreathing, pinholing, casting spot, cracking, poor drainage. Stirring and sieving, pouring slip, testing thickness of casting, draining, opening mould and removal, fettling. 5. Proportion, rhythm, balance of line, tone and colour; sgraffito, wax resist, slip trail, oxides and glaze stains, stencils, agate ware, impressed, incised, coloured glass, ceramic transfers, onglaze enamel etc. 6. Biscuit firing cycle, handling greenware, use of props and bats, use of slits, saddles and kiln placing powder. Bat wash, glaze firing cycle. 7. Seger formula, glass makers, function of fluxes and amphoteric oxides. Commonly used glaze ingredients, and their main function in the glaze. The ratio of flux to glass maker indicating melting temperature and amphoteric oxide to flux controlling viscosity. Commonly used metal oxides and the colours produced in fritted lead, alkaline glaze, under oxidation or reduced conditions. Cooling time and crystallisation. Glaze defects such as crazing, crawling, pinholing, running, shivering

8 SUGGESTED LEARNING AND TEACHING APPROACHES The learning approach should be activity based and centred on practical exercises with a well designed brief. Since much time in the module could be lost waiting for layers of soap to dry, plaster to set, moulds to dry, castings to set and drain, it should be possible to use this time in the production of a single piece open mould. This would provide the opportunity to experiment with slip trailing on the wet casting slip or to practise other decorative techniques. It may also be possible to extend the Outcomes and produce a block mould, or even one section of a block mould, once the mould has served its purpose for this module. Tutors should note that the multi-piece moulds may be 2, 3 or 4 piece moulds. In Outcome 2, if a 3 or 4 piece mould is prepared, it will require the use of end bats to ensure that the mould can be screeded to produce a mould of neat finish and uniform thickness. It will also require the use of a tapered based plug that fits accurately on the footring to produce a base section of the mould that fits tightly. It should be noted that a number of the Outcomes in this module are common to other ceramics modules. Students who have successfully completed these modules will have already gained the skills but will require in this module to practise these skills across a different range of activities ie. those related to slip cast ware. Copyright SQA